NET Compact Framework 3.5 Data-Driven Applications: Build robust and feature-rich mobile data-driven applications with the help of real-world examples

NET Compact Framework 3.5 Data-Driven Applications Build robust and feature-rich mobile data-driven applications with ...

Author: Edmund Tan

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.NET Compact Framework 3.5 Data-Driven Applications Build robust and feature-rich mobile data-driven applications with the help of real-world examples

Edmund Tan

BIRMINGHAM - MUMBAI

.NET Compact Framework 3.5 Data-Driven Applications Copyright © 2010 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews. Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, Packt Publishing, nor its dealers or distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book. Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: April 2010

Production Reference: 1220410

Published by Packt Publishing Ltd. 32 Lincoln Road Olton Birmingham, B27 6PA, UK. ISBN 978-1-849690-10-2 www.packtpub.com

Cover Image by Vinayak Chittar ([email protected])

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Credits Author

Editorial Team Leader

Edmund Tan

Gagandeep Singh

Reviewer

Project Team Leader

Greg Yap

Lata Basantani

Acquisition Editor

Project Coordinator

David Barnes

Srimoyee Ghoshal

Development Editor

Proofreader

Rakesh Shejwal

Sandra Hopper

Technical Editors

Graphics

Neha Damle

Geetanjali Sawant

Rukhsana Khambatta Production Coordinator Shantanu Zagade

Copy Editor Sanchari Mukherjee

Cover Work Shantanu Zagade

Indexer Monica Ajmera Mehta

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About the Author Edmund Tan is the CTO and co-founder of a leading e-forms and workflow

solution vendor based in Singapore. He holds more than eight years of experience building performance-critical .NET e-forms and workflow solutions for smart devices on top of Oracle and Microsoft SQL Server databases for large companies and governmental institutions located in Singapore and Malaysia. Edmund is also a regular public speaker at various conferences held in Singapore and Malaysia on the topic of on-the-go BPM (Business Process Management) hosted on smart device technologies. During his free time, Edmund works on trying to create machines capable of emulating human thought. My first and heartfelt word of thanks goes out to David Barnes without whom this book would not have been possible at all. I also thank James Lumsden for giving my e-mail a chance, Rakesh Shejwal and Greg, my long-time collaborator, for their always insightful edits, Srimoyee Ghoshal for keeping me on schedule, Lata Basantani, as well as everyone else involved in this book at Packt. I extend my gratitude to my parents, Laumee and Obagi, for their undying love and support, my aunt Laumar for instilling the bookworm in me, my wife Shen for keeping the beverages flowing, my kid Sophie simply for being the pride of my life, and, last but not least, my brother Edwin for his jokes during the really, really late hours of the night.

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About the Reviewer Greg Yap is a tech-savvy person who's always interested in the latest technology. He has worked on .NET since its first release. He has experience in developing software for small, medium, and enterprise-sized companies around the world and has worked on Microsoft technologies for a variety of platforms including the .NET Compact Framework. He is also well versed in the C# and VB.NET programming languages. I would like to thank my family, especially my understanding wife Jennie who's given me all the support and time I needed to review this great book. To my two kids—thank you! I'm glad that both of you have shown the patience I knew you would. My thanks also go out to my friend Edmund for having considered me as the technical reviewer for this book—I owe you a coffee! Last but not the least, I would like to thank Srimoyee Ghoshal for always being there to keep me on time and the remaining Packt Publishing team for giving me the opportunity to review this book.

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Table of Contents Preface Chapter 1: CRMLive.NET: An Overview

1 9

Tomorrow Inc. The mobile sales force application The mobile dashboard application The mobile support case application Data flow in CRMLive.NET Deciding on the type of mobile application Thin clients Thick clients Smart clients Messaging A brief summary Defining the mobile sales force application Capturing lead, opportunity, and customer information

10 10 11 12 12 13 13 14 14 15 15 16 17

Task management Full-text search functionality Integrating with Windows Mobile and the hardware

20 21 22

Data synchronization Dual database support Application maintenance and upgrades

25 25 25

Mobile screen design Creating reusable controls Maintaining global lists Data retrieval and manipulation on the mobile device Data transfer between multiple mobile devices

Detect incoming phone calls and SMS Integrating with the Windows Mobile Calendar and Contacts book Data exchange using Bluetooth and IrDA Capturing handwritten input

18 19 19 20 20

23 23 24 24

Table of Contents

Defining the mobile dashboard application Using stateless web services as a data source Rendering the dashboard

25 26 27

Defining the mobile support case application Building a messaging backbone with MSMQ Summary

28 29 30

Road show revenue Total monthly sales Sales for last three months

Chapter 2: Building the Data Tier

Designing the data tier SQL Server CE 3.5 versus Oracle Lite 10g Connecting the Windows Mobile emulator to ActiveSync Setting up SQL Server Compact 3.5 Installing SQL Server CE on the development machine Installing SQL Server CE on the Pocket PC device. Setting up Oracle Lite 10g Installing Oracle Lite 10g on the development machine Installing Oracle Lite 10g on the Pocket PC device Building the data tier Building the CRMLiveFramework project Defining the IDataLibPlugin interface Building the Plugin Manager UI An overview Implementing the PluginCollection class Implementing the PluginManager class Creating the SalesForceApp project Building the ConfigurePlugin form Building the PluginsSetup form Testing what you've built so far Building the database plugins Implementing the SQL Server CE Plugin Storing DDL in the resource file Building the plugin class Connecting to SQL Server CE Programmatically creating the SQL Server CE database Testing what you've done so far

27 28 28

31 31 32 33 35 35 36 37 37 38 38 39 40 43 44 46 46 50 50 54 58 59 60

60 63 64 65 67

Browsing the SQL Server CE database with Query Analyzer

68

Implementing the Oracle Lite plugin

75

Retrieving data from SQL Server CE Data manipulation in SQL Server CE Dealing with GUID values in SQL Server CE Storing DDL in the resource file

[ ii ]

70 71 74 75

Table of Contents Building the plugin class Connecting to Oracle Lite Programmatically creating the Oracle Lite database

Browsing the Oracle Lite database with Msql Retrieving data from Oracle Lite Data manipulation in Oracle Lite Dealing with GUID values in Oracle Lite

Summary

Chapter 3: Building the Mobile Sales Force Module

A brief walkthrough of what you will be building Building a form navigation class Building the main menu Using Main() as the startup object Creating the business objects to encapsulate your DataSets Validating data in your business objects Building the AccountViewer form Data binding .NET controls to your business objects Launching the AccountViewer form Testing the AccountViewer form Building the Tasks list Populating the Tasks Datagrid control Building the TaskDetailViewer form Launching the TaskDetailViewer form Testing the tasks list Handling file attachments Building a file manager class Building the FileUpload user control Building the FileDetailViewer form Testing file upload functionality Custom formatting and display in list controls Building a collection sorter using the IComparer interface Custom formatting and display in the list control Using the History list control Testing the History list control Building the ProductList control Using XML DOM to store and retrieve product selection Using the ProductList control Testing the ProductList control Building a paged listing of accounts Paging in SQL Server CE Paging in Oracle Lite [ iii ]

77 77 78

80

81 81 84

85

87

88 94 96 98 100 108 109 111 111 114 114 115 116 119 120 120 121 123 126 128 129 130 131 135 136 136 139 141 142 142 143 146

Table of Contents

Building a paging user control Creating a context menu for the paging user control Launching the accounts listing page Testing the accounts listing page Summary

Chapter 4: Building Search Functionality

A brief walk-through of parameterized search Building the parameterized search feature Creating the parameterized search query in SQL Server CE Creating the parameterized search query in Oracle Lite Encapsulating the retrieved Dataset using business objects Building the parameterized search forms Building the search form Building the search results listing form Trying out your code

A brief walk-through of full-text search Building the full-text search feature Creating the Keyword Extractor classes A sample keyword extractor—the HTML Keyword Extractor Indexing the file Creating the full-text search query for SQL Server CE Creating the full-text search query for Oracle Lite Encapsulating the retrieved dataset using business objects Creating the full-text search forms Trying out the full-text search Improving the full-text search engine Summary

Chapter 5: Building Integrated Services

Sending SMS and e-mail from your application Sending SMS and e-mail directly through code Delegating to the default Windows Mobile Compose UI Intercepting incoming SMS Intercepting an SMS message Placing phone calls from your application Detecting incoming phone calls Populating the History tab in the sales force application Creating the data tier functions to insert historical records Encapsulating SMS functionality Encapsulating phone functionality Intercepting incoming SMS messages and phone calls in the background [ iv ]

147 150 151 152 152

155 156 157 160 163 164 165

165 168 168

169 171 172 173 174 175 182 185 185 190 190 191

193 193 194 196 196 197 198 199 200 201 204 206 208

Table of Contents

Handling outgoing SMS messages and phone calls Testing your code Synchronizing with Windows Mobile Contacts Synchronizing with Windows Mobile Tasks Sharing an account between two devices Sharing an account between two devices using Infrared (IrDA) Sharing an account between two devices using Bluetooth Capturing handwritten input using the Smart Device Framework Summary

Chapter 6: Data Synchronization

Overview of the different data synchronization methods available for Microsoft SQL Server CE SQL Remote Data Access (SQLRDA) Merge replication Microsoft Synchronization Services Overview of the different data synchronization methods available for Oracle Lite Oracle Mobile Server A quick comparison between the various Synchronization frameworks Using Microsoft Synchronization Services Setting up Microsoft SQL Server and Microsoft Synchronization Services Creating the CRMLive server tables Creating the WCF service Configuring the WCF service library Setting filters for the Sync

Configuring the client project Writing the sync code Conflict resolution Using Oracle Mobile Server Installing Oracle Database Enterprise 11g and Oracle Mobile Server Creating an Oracle Mobile repository Creating the CRMLive server tables Creating a new publication using the Mobile Database Workbench Creating a new mobile project Adding publication items to your project Adding sequence items to your project Adding a publication to your project

Publishing the mobile application to the mobile server Setting up application users using the WebToGo portal

[v]

212 215 216 219 220 222 227 230 235

237 238 238 238 239 240 240 241 242 242 243 243 246

248

250 253 255 256 257 258 260 262

262 264 268 270

273 275

Table of Contents

Registering the mobile device with the mobile server Synchronizing with the mobile server Synchronizing files with the server Creating network-aware synchronization modules Summary

279 280 281 283 284

Chapter 7: Optimizing for Performance

285

Using BeginUpdate and EndUpdate Using SuspendLayout and ResumeLayout Load and cache forms in the background

302 302 303

Measuring performance Measuring .NET CF code performance Capturing application performance statistics Optimizing database performance Data caching Using database indexes to boost search performance Other database optimization tips Optimizing data transfer performance Managing better code Managing better strings Managing better Winforms

Managing better XML

Using XMLTextReader and XMLTextWriter XML serialization and deserialization thesis

Managing better files The .NET Compact Framework garbage collector Summary

286 286 289 292 293 295 297 297 300 301 302

303

303 304

304 304 306

Chapter 8: Securing the Application

307

Chapter 9: Globalization

323

Encrypting the database Encrypting the SQL Server CE database Encrypting the Oracle Lite database Authenticating the sales force application Performing one-way encryption using SHA256 Writing the code for authentication Loading the login form Encrypting data for inter-device transmission using AES Summary Supporting double-byte languages Supporting Japanese character input in Windows Mobile Supporting Unicode at the application level [ vi ]

307 308 309 309 310 312 317 319 322 323 324 324

Table of Contents

Designing culture-sensitive forms Retrieving culture information Summary

326 330 331

Chapter 10: Building the Dashboard

333

Chapter 11: Building the Support Case System

365

An overview of the dashboard Creating the web service Creating the dashboard smart client Connecting to the web service Creating the line chart Creating the round gauge Creating the bar chart Summary

Introduction to MSMQ and the support case system Setting up MSMQ on your mobile device Writing your first MSMQ application Setting up MSMQ on your server Creating a queue on the server manually using the computer management panel Sending a message from the server to a remote mobile device Sending data to a remote queue Creating the server-side application Creating the client-side application Sending a message from the mobile device to the server Writing the client-side code Writing the server-side code Summary

Chapter 12: Testing and Debugging

Overview of Power Toys for .NET CF 3.5 Installing Power Toys for .NET CF 3.5 Using the Remote Performance Monitor and GC Heap Viewer tool Memory leaks and their causes A sample application with memory leak Using the Remote Performance Monitor tool to view application statistics in real time Using PerfMon to graphically view runtime performance statistics Using the GC Heap Viewer tool to detect memory leaks Resolving the memory leak

[ vii ]

333 334 338 338 341 350 356 363 366 369 371 377

378 379 379 380 385 389 389 390 392

393 394 394 395 395 396 398 400 403 404

Table of Contents

Using the CLR Profiler tool A sample application with bad performance Launching the application with the CLR Profiler tool Inspecting the Histogram view Inspecting the Allocation Graph Inspecting the Time Line view Inspecting the Call Tree view Using the App Configuration tool Using the ServiceModel Metadata tool Using the Remote Logging Configuration tool Using the Network Log Viewer tool Summary

405 406 409 410 411 412 415 417 419 421 423 424

Chapter 13: Packaging and Deployment

425

Index

455

Deploying your solution as a CAB file Adding the SalesForce application files to your CAB project Configuring other miscellaneous settings Deploying your solution as an MSI file Creating an INI file Creating the custom action DLL Creating the MSI installer project Creating an automated update service Creating the server-side web service Creating the client-side updater tool Summary

[ viii ]

426 427 430 432 433 433 438 442 442 445 454

Preface As business systems become increasingly distributed, the mobile device becomes an increasingly important tool on the enterprise stage. The large amount of processing power available to mobile devices nowadays bring to it a whole new range of possibilities as a mobile extension to traditional server-based enterprise systems. Harnessing this power is the .NET Compact Framework, which has seen tremendous improvements over the last few versions. The .NET Compact Framework provides a rich set of managed classes that does away with a big chunk of the menial labor required to perform common tasks, leaving the developer to focus on building business logic instead. This book is not intended to be a complete reference tome of the .NET Compact Framework. There are numerous books and documentation online that serve this purpose. Rather, it will show you how to apply the .NET Compact Framework in interesting ways to solve real-world business problems. We will explore commonly encountered design decisions and technology comparisons along the way and ultimately build clean solutions that keep to best practices such as the three-tier design and the Model View Controller (MVC) model. Using a sales force application as the central example and theme in this book, you will have a clear step-by-step guide on building one of the most popular types of business applications in the market today from ground up. Through these pages, you will learn how to create robust data-driven mobile applications that work seamlessly with other mobile devices and database servers. You will get to explore the little nuances of .NET Compact Framework programming, and how to get around them using its advanced features. You will also get a firsthand look at how you can use third-party libraries such as the open source Smart Device Framework to add a host of rich functionality to your applications.

Preface

Towards the end of this book, you will have accumulated enough understanding of the capabilities and limitations of the .NET Compact Framework and its tools to confidently tackle an enterprise mobile application of any size or complexity. I hope in the process of getting there you will have as much fun reading this book and trying out the samples as I had writing it.

What this book covers

Chapter 1, CRMLive.NET: An Overview, provides a technical and scope overview of CRMLive.NET, a mobile customer relationship management suite comprising three individual applications (a mobile sales force, mobile dashboard, and mobile support case application). Chapter 1 also outlines the four different mobile client models and a comparison of their strengths and weaknesses. Chapter 2, Building the Data Tier, shows how a plugin-based data tier based on both the Microsoft SQL Server Compact and Oracle Lite databases can be created using ADO.NET. Chapter 3, Building the Mobile Sales Force Module, walks the reader through building the logic and presentation tiers of the mobile sales force application, illustrating various concepts along the way such as UI object reusability, validation, paging, record navigation, sorting, and grouping. Chapter 4, Building Search Functionality, illustrates how full-text search and parameterized-search functionality can be added to the mobile sales force application. Chapter 5, Building Integrated Services, illustrates how the sales force application can make use of the .NET Compact Framework and P/Invoke calls to access underlying Windows Mobile operating system and mobile device functionality such as the Bluetooth, Infrared, Calendar, and Telephony services. Chapter 6, Data Synchronization, covers one of the most important topics in the book—the process of data synchronization between the mobile device and the remote database. In this chapter, we will look at how the sales force application can perform bidirectional synchronization using Microsoft SQL Server Compact's SQL RDA and Oracle Lite's mSync technologies. Chapter 7, Optimizing for Performance, illustrates how the sales force application's performance can be measured and improved using various techniques such as data caching and data compression.

[2]

Preface

Chapter 8, Securing the Application, covers the various ways to secure locally stored data on the mobile device. It also covers the various authentication mechanisms available during data synchronization with the remote database. Chapter 9, Globalization, illustrates how the reader can globalize the sales force application to intrinsically support double-byte (Unicode) languages. Chapter 10, Building the Dashboard, walks the reader through the building of the second application in CRMLive.NET—the mobile dashboard. It will cover the use of stateless asynchronous web service calls to retrieve XML-based data from a remote server. Chapter 11, Building the Support Case System, walks the reader through the building of the third application in CRMLive.NET—the mobile support case application. It will cover how a messaging backbone based on Microsoft Messaging Queue (MSMQ) technology can be built to support disconnected-state messaging between two remote applications. Chapter 12, Testing and Debugging, looks at how the tools provided in the PowerToys for .NET CF 3.5 suite can assist in the testing and debugging process of the CRMLive. NET application. Chapter 13, Packaging and Deployment, walks through the packaging and deployment process of the CRMLive.NET application and how a network-aware, automated update service can be created to assist in the deployment of application upgrades.

What you need for this book

This book provides all source code in both VB.NET and C#. To run most of the code samples in this book, you will need the following basic tools: • • • • •

A suitable development workstation with Microsoft Visual Studio 2008 Windows Mobile 6 SDK (includes an emulator for you to test your .NET CF applications) Microsoft ActiveSync 4.5 (for Windows XP machines) or Microsoft Mobile Device Center (for Windows Vista machines) The .NET Compact Framework 3.5 redistributable The Microsoft SQL Server Compact 3.5 database

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Preface

Throughout the book, we will also encounter certain technologies and products when we build our application. The following lists the other products used in the book: •

•

•

•

In Chapter 2, we will show how the data tier can also be built to support the Oracle Lite database. To run the Oracle Lite code samples, you will need to download and install Oracle Lite 10g. In Chapters 5 and 10, we make use of the Smart Device Framework to handle specific requirements in the CRMLive.NET application. To run the code samples in these chapters, you will need to install the Community Edition of the Smart Device Framework v. 2.3.0.39 (at the time of writing). In Chapter 11, we will be building a messaging backbone on top of the Microsoft Messaging Queue service. You will need to install the MSMQ service on the mobile device. In Chapter 12, we will cover the tools provided in the PowerToys for .NET CF 3.5 suite (provided by Microsoft) to test and debug the CRMLive.NET application. You will need to install this product to try out the samples in this chapter.

Who this book is for

This book is primarily targeted at developers who are new to the .NET Compact Framework and wish to embark on data-driven mobile application development in an enterprise scenario. All code samples included in this book are in VB.NET and C#. This book assumes you are familiar with either the Visual Basic.NET or C# language. It does not require you to have any prerequisite experience or knowledge of the .NET Compact Framework. This book is also targeted at: •

•

Developers who are already familiar with the .NET Compact Framework, but want to learn about how it can be effectively used to tackle commonly faced problems in real-life business scenarios Developers who want to learn how to use the .NET Compact Framework to access core Windows Mobile 6.0 and device functionality

Most of the samples in this book are targeted at the Windows Mobile operating system. Some basic knowledge of the Windows Mobile operating system would be beneficial, but not necessary.

[4]

Preface

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning. Code words in text are shown as follows: "We can include other contexts through the use of the include directive." A block of code will be set as follows: public string PluginDatasource { get { return _PluginDatasource; } set { _PluginDatasource = value; } }

When we wish to draw your attention to a particular part of a code block, the relevant lines or items will be shown in bold: public bool SetAccountDetails(Guid AccountGUID, System.Data.DataSet Account) { SqlCeDataAdapter _adapter; SqlCeTransaction _transaction; }

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in our text like this: " Open Windows Mobile Device Center and click on Connection Settings under Mobile Device Settings. " Warnings or important notes appear in a box like this.

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or may have disliked. Reader feedback is important for us to develop titles that you really get the most out of. [5]

Preface

To send us general feedback, simply drop an e-mail to [email protected], and mention the book title in the subject of your message. If there is a book that you need and would like to see us publish, please send us a note in the SUGGEST A TITLE form on www.packtpub.com or email [email protected]. If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide on www.packtpub.com/authors.

Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase. Downloading the example code for the book Visit https://www.packtpub.com//sites/default/files/ downloads/0102_Code.zip to directly download the example code. The downloadable files contain instructions on how to use them.

Errata

Although we have taken every care to ensure the accuracy of our contents, mistakes do happen. If you find a mistake in one of our books—maybe a mistake in text or code—we would be grateful if you would report this to us. By doing so, you can save other readers from frustration, and help us to improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub. com/support, selecting your book, clicking on the let us know link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata added to any list of existing errata. Any existing errata can be viewed by selecting your title from http://www.packtpub.com/support.

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Preface

Piracy

Piracy of copyright material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works in any form on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy. Please contact us at [email protected] with a link to the suspected pirated material. We appreciate your help in protecting our authors, and our ability to bring you valuable content.

Questions

You can contact us at [email protected] if you are having a problem with any aspect of the book, and we will do our best to address it.

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CRMLive.NET: An Overview Mobile device programming by itself can be a serious test of software engineering skill, where coders are usually forced to work with a fraction of the resources available compared to the full .NET Framework. Screen area, processor speed, memory, and disk space available stand at a fraction of what one would generally get with a desktop computer. In fact, the .NET Compact Framework implements only thirty percent of the full .NET Framework, doing away with a large subset of the classes deemed to be unsuitable for the small footprint required of a mobile application. In such a resource-tight environment, the wrong design decisions can often lead to an underperforming application, a clunky interface that irritates users, or worse—grinds to a halt when deployed in an enterprise scenario where hundreds of instances of the application need to exchange and sync data in synchrony. As you progress through this book, you will find that the three-tier model recurs throughout all chapters. In each approach, you will learn how to think a few steps ahead and adopt designs that allow the various components you are building to fit in together elegantly. We start this first chapter by exploring an overview of game developer Tomorrow Inc. and CRMLive.NET, a mobile customer relationship management suite that we will be building for this company. By the end of this chapter, you will obtain: •

A first-hand look at how the end product you are developing will look

•

A general overview of the functional scope of CRMLive.NET

•

A look at the various designs undertaken in CRMLive.NET and why they work best in each scenario

•

An understanding of the various classes in CRMLive.NET and their interactions

•

An overview of the various .NET Compact Framework technologies you are going to use along the way

CRMLive.NET: An Overview

Tomorrow Inc.

Tomorrow Inc. is a cutting edge gaming company of about 5,000 employees based in New York with branches around the world. They have recently developed a technology that immerses the gamer in a virtual world and are planning to launch their first MMIG (Massively Multiplayer Immersive Game), titled 'Rabbits from Hell' at a road show in New York and Tokyo at the same time. The products include a virtual reality chair, simply known as 'The Chair,' which is basically an interface to the game that allows full unrestricted physical motion from the player. Used together in conjunction with a set of Virtual Reality goggles, it brings gaming realism to a whole new level by immersing the player completely in the game. The Chair is about the size of an armchair and after purchase, a visit will be typically arranged by Tomorrow Inc. technicians to deliver and install the product in the customer's home. The road show is the biggest ever launch in the history of Tomorrow Inc., stationing about 100 salespersons at the event itself and another 50 on the streets for a total duration of three weeks. Tomorrow Inc. needs a suite of mobile applications: CRMLive.NET to cater to the needs of three different levels of staff—the salesperson, the boss, and the technician.

The mobile sales force application

Tomorrow Inc. needs a mobile sales force application that will allow its salespersons to capture and manage leads, opportunities, and customers at the event. Before we proceed with the technical requirements, let's explore Tomorrow Inc.'s business a little further in detail. A 'lead' is a sales term that applies to someone who shows an interest in the product, but how genuine he or she is about buying it has not yet been ascertained. It is usually the intention of the salesperson to convert a lead (a curious prospect) into an 'opportunity' (a serious potential buyer) and eventually into a buying customer. At any one time during and after the launch of the game, there will be a mix of people from all three categories. There are the curious onlookers at the road show who casually enquire about the game. These people fall under the leads category. Then there are those who have been hounded by salespersons for weeks. They have the money and do show a genuine interest to buy, but need a little more coaxing. These are 'opportunities'. Finally, there are the frenzied young kids who have camped outside the road show hall since 2 a.m., having saved up their entire life savings anticipating the game release. These are undoubtedly buying customers.

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Chapter 1

Tomorrow Inc. is forecasting a huge flood of visitors to its road show, and has placed a strong emphasis on a lean UI design that can streamline quick data capture and access. The following list highlights the core requirements of this application in brief: •

Capable of lead, opportunity, customer, and task management

•

Must have quick and responsive UI

•

Must support offline access to stored information (when a network connection is unavailable)

•

Must support strong personalization features

•

Must be highly secure—Tomorrow Inc. is anticipating the possibility of lost mobile devices and wishes to protect locally stored information

•

Must be capable of fast full-text search (searching within file attachment content and the entire database)

•

Salespersons may decide to share leads at any point in time. The application must be able to transfer leads from a mobile device to another easily

•

Must have dual database support—due to incredibly poor IT budget management, half of Tomorrow Inc.'s servers are hosted on Oracle, with the other half hosted on Microsoft SQL Server Enterprise. Extending this to the mobile device, this means that Oracle Lite Edition and Microsoft SQL Server Compact Edition support will be necessary

•

Authentication must make use of Tomorrow Inc.'s existing ActiveDirectory setup

•

Must provide Japanese-language support for users at the road show in Tokyo

The mobile dashboard application

The boss of Tomorrow Inc. travels across country frequently by train; his trips usually take him through areas with little or no Internet connectivity. His requirements are primarily centered on a mobile dashboard application that allows real-time monitoring of sales figures and Key Performance Indices (KPIs). His requirements include: •

Must provide customizable dashboard views

•

Must have real-time access to the latest data from the server

•

Must be able to display information visually in the form of interactive charts and gauges

[ 11 ]


The mobile support case application

After the customer purchases a game account, the Tomorrow Inc. technician will need to make a visit to the customer's residence to install and deploy The Chair. Before that can happen, the following series of actions will first take place: 1. A data entry clerk at the Tomorrow Inc. office will create a job at the server. 2. Once a job is created, it will be broadcast to all technicians on the field over the Internet. 3. The technicians can then choose to accept a job via the mobile application. The accepted job is subsequently removed from the list of jobs at the server. The core requirements for this application include the following: •

Must be able to broadcast/push new jobs to individual mobile devices over the Internet even if these devices are offline

•

Must be able to propagate the technician's actions back to the server

Data flow in CRMLive.NET

Based on the requirements outlined in the previous section, we can roughly summarize the data flow of CRMLive.NET in the succeeding diagram. CRMLive. NET comprises three separate and distinct applications that tap into the same central data source. The sales force application is the key application that provides data to fuel the rest of the system. You will notice from the diagram that mobile devices running the sales force application can also share data directly with each other. This is because salespersons at the event may decide to transfer their leads and opportunities to their colleagues. At the end of the day, all data entered through the sales force application is eventually synced up to the central database. The support case system will make use of information captured from new customers, such as their residential addresses and phone numbers, to generate new jobs for the technicians. The mobile dashboard on the other hand will periodically retrieve sales-related data (keyed in when new customers are created) directly from this central database every minute. This sales data is converted into visual charts for display on the mobile dashboard.

[ 12 ]

Chapter 1

Customer info Tomorrow Inc CRMLive.com

Customers, Leads & Opportunities Internet

Support Case

SYNC UP Device-to-device data sharing Central Database Sales Force Internet

Sales info

Mobile Dashboard

Each of these three applications access data in a different way. In all three scenarios, the central database can be accessed over the Internet as well as over an Intranet. We will also explore the different ways to protect data transmission and access throughout CRMLive.NET in the later chapters of this book.

Deciding on the type of mobile application

There are four different ways to deploy a mobile application, each with their own benefits and downsides. Before you decide on the type of model to use in your applications, let's take a look at them in further detail.

Thin clients

Applications deployed on a thin client model are accessed through browsers on the mobile device, called mobile browsers or alternatively, mini browsers, or wireless Internet browsers. They are essentially scaled-down versions of a full-blown browser. For instance, the default preinstalled browser that comes with the Windows Mobile operating system, Internet Explorer Mobile, is a mobile browser.

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In the thin client model, application code and data are not stored on the mobile device. Just like traditional web-based applications, all the work is done at the server, and each page is served up on-demand as they are accessed from the mobile device. Thin-client applications, therefore do not require the installation of any additional software other than the mobile browser.

Thick clients

Thick clients run entirely on the mobile device and store both code and data locally. It must be installed on the mobile device prior to usage. Thick clients typically utilize a mobile database installed on the same mobile device such as Microsoft SQL Server Compact or Oracle Lite. It is common for thick clients to transfer its data from the local database to a remote and central database periodically so that it can be shared with other units. This process is called data synchronization. The basic set of features you would find common across thick clients include: •

A responsive and interactive UI

•

Ability to store data locally in a mobile database

•

Ability to synchronize data with a database on a remote server

Smart clients

A smart client, sometimes known as a rich client lies somewhere between a thin client and a thick client. Code is still stored locally on the mobile device, but data is stored on a remote server. Data (commonly in the form of XML) is retrieved from or updated to the server in an on-demand fashion whenever needed. There are various ways over which this data exchange can take place, the most common being web service calls, made over the SOAP (Simple Object Access Protocol) interface. As smart clients still render the UI of the application locally, it has the benefit of a responsive and rich interface. However, smart clients do not have to worry about data synchronization as all data manipulation is done in real time (via web service calls). Smart clients are suitable for projects where: •

There are lists of frequently changing information, such as global pricelists that need to be frequently updated on the mobile device.

•

Developers need the flexibility of a customizable and responsive UI together with real-time data transactions.

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Chapter 1

Messaging

Lastly, messaging-based mobile applications make use of services such as SMS (Short Messaging Service) and e-mail to drive the interaction between the user and the application. Like the thin client model, it does not require installation of any specific software other than the messaging application itself. For example, a stock price enquiry service may involve the following actions: •

A mobile user sends an SMS containing the stock symbol of the desired stock to a special number

•

This incoming SMS is processed by the server-side application, which then queries the database and retrieves the corresponding stock price for the symbol.

•

The stock price is then sent back to the user via SMS

A brief summary

The following table summarizes the various strengths and shortcomings of each type of mobile application: Feature

Thick client

Thin client

Smart client

Messaging

Requires installation/stores code locally on the mobile device

Y

N

Y

N

Requires live network connection to the application server

N

Y

N

N

Stores data locally and requires database on the mobile device

Y

N

N

N

Allows application to access low level device functions

Y

N

Y

N

Middleware requirements on the mobile device

.NET CF,

Mobile Browser

.NET CF

Messaging application

UI responsiveness

High

Low

Medium

High

UI richness/interactivity

High

Low

High

Low

Ease of development

Low

Medium

Medium

High

Security

High

Medium

Medium

Low

Ease of application update and maintenance

Low

High

Low

High

Mobile Database

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Feature

Thick client

Thin client

Smart client

Messaging

Ideal for high transactional volume

Y

N

N

Y

Ideal for data transactions that are large in size (example : file attachments)

Y

N

N

N

Ideal for complex input data (example : forms involving multiple field input)

Y

Y

Y

N

Ideal for complex data input methods (example : digital signatures, barcode scanning)

Y

N

Y

N

Application data latency

Non real-time

Real-time

Real-time

Real-time

Support for different operating systems/devices

Low

High

Low

High

Defining the mobile sales force application

We will first take a look at the mobile sales force application and try to decide on a suitable client model. Looking at the earlier chart, a thick client model would best fit the requirements of this application due to the two key requirements of a responsive UI and offline access support. You may have also considered the smart client model for this task, but there is no requirement for real-time data transactions in this application. A local database works better in this case because it eliminates network latency that would otherwise be present on the smart client (due to remote database access). Furthermore, a smart client model would not work well in areas without a network connection.

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Chapter 1

In the following sections, we walk through the main functionality of the application and outline the various .NET Compact Framework technologies that will be used in the process.

Capturing lead, opportunity, and customer information

Tomorrow Inc. is anticipating a very large turnout at the road show; your users will need 'at a glance' access to key information as well as easy navigation across the various data entry windows.

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Mobile screen design

To cite an example of a screen design that is the product of objective thought, consider the following Lead Details form:

You might be used to the idea that phone numbers, street addresses, and e-mail addresses are related and should all go together under a single Contact Details tab. Thinking objectively though, the salesperson would likely spend more time trying to follow up on a lead making phone calls rather than holding face to face meetings at the lead's address. In this case, it makes for a better design to have the phone number and not the address on the first screen. When we build this application later on in the book, you will encounter other similar examples and learn how you can minimize the need to switch between tabs by placing the most commonly used fields in a single screen. We will also extend the idea of objective design to the toolbars and menus in the application, covering best practices and how efficient use of these controls can help reduce on-screen clutter.

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Chapter 1

Creating reusable controls

You may have also noticed from the previous screenshots that we have placed various icons next to the phone number fields. They allow the user to initiate a phone call or send an SMS directly using the number in the adjacent text box. This control, called the PhoneNumber control (shown in the following screenshot), is one of the various Usercontrols that we will build and reuse throughout this application.

Maintaining global lists

You will also learn how to implement a simple checklist such as the Interested product(s) checklist shown in the succeeding screenshot using the .NET Compact Framework's Listview control.

To make things interesting, we will also feature a dynamic product list that can change any time at the remote server end. We will explore how a sync in the opposite direction (from server to mobile device) can be used to update global lists like this in your application.

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Data retrieval and manipulation on the mobile device

As this is the first section dealing with data retrieval and manipulation, we will also get a first-hand look at the ADO.NET libraries and how we can make full use of the library to execute SQL queries against the local database to retrieve and manipulate sales force data. We will cover data access and ADO.NET in full detail when we build a generic data layer in Chapter 2, Building the Data Tier.

Data transfer between multiple mobile devices

Transferring data between one mobile device and another is a common requirement in most enterprise scenarios and our sales force application is no exception. At any point in time, a salesperson may decide to hand over a lead to another colleague, possibly because he or she is not interested in following up on that lead. Passing the lead to another person means that the receiving party needs to have the lead details and all other relevant data transferred to his mobile device. There are a few different approaches to data transfer, which we will cover in detail when the time comes, but for this application we will concentrate on using both Infrared and Bluetooth technology to transfer a lead record (in compressed XML format) directly from one device to another.

Task management

One of the reasons for building a task management module in this application is to allow the salesperson to manage tasks that are lead and opportunity specific. We will choose to implement the task listing using the .NET Compact Framework's DataGrid control due to its rich set of data formatting and data binding capabilities. You will also learn the basics of using the DataGrid control in this section and how to get around its limitations. We will also cover the following subtopics: •

How to data bind an ADO.NET data source to the DataGrid control

•

How to implement data paging at the SQL level

•

How to create columns with multiple sorting

•

How to handle data and cell formatting in the DataGrid control

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Chapter 1

Full-text search functionality

Being able to search within the content of a file and entire databases via an incredibly simple UI comprising a text box and a button is indeed very attractive to any mobile user. We will build a similar search engine for the sales force application. It will be capable of searching within file content, file names, and database records all at one go.

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Microsoft SQL Server Compact and Oracle Lite needs to operate with a small footprint and, unfortunately, does not provide any full-text search feature. We will take it upon ourselves to create a simplified version of the full-text search service of our own. You will learn how to do the following from this exercise: •

How to index the contents of a file for full-text search

•

How to handle wildcard and binary searches (the ability to combine multiple search phrases with AND and OR conditions)

•

How to create column indices in Microsoft SQL Server Compact and Oracle Lite to improve the performance of full-text search queries

The following screenshot shows what the search results listing will finally look like in your application:

Integrating with Windows Mobile and the hardware

The mobile device is usually packed with useful hardware and operating system features like telephony, GPS, SMS, and Bluetooth, just to name a few. You can use the libraries in the .NET Compact Framework and the open source Smart Device Framework to access a large range of such functionality from your application. Looking at an example of how this can work with your sales force application, consider phone number displays in your application. As you saw earlier, you will be creating a reusable PhoneNumber usercontrol that allows users to easily place a phone call or send an SMS message. You will learn how you can call the Windows Mobile classes in the .NET Compact Framework libraries to achieve this. Most of what follows in this section refers to application features discussed earlier. [ 22 ]

Chapter 1

Detect incoming phone calls and SMS

We will in fact extend this functionality further using the .NET Compact Framework Message Intercept classes to detect incoming phone calls and SMS. You will see how you can use these events to automatically generate historical log entries for every lead. This allows the salesperson to see a comprehensive history of all correspondence with a particular lead.

Integrating with the Windows Mobile Calendar and Contacts book

If you recall, we had to implement a lead and opportunity-specific task list in this application. What is also unique about this task list is that a copy of the tasks will be automatically pushed to the Windows Mobile Calendar. This allows you to tap into the reminder services in Windows Mobile to remind the user of an impending task. You will learn how to integrate with the Windows Mobile Calendar and Contacts services using the .NET Compact Framework libraries to achieve this functionality.

The benefits are twofold. In addition to not having to reinvent the wheel, this sort of integration opens up a host of functionality behind the scenes. For instance, by placing a copy of the lead- and opportunity-specific tasks in the Windows Mobile Calendar, the user will be able to eventually sync them to Microsoft Outlook on his desktop PC via ActiveSync. This feature is immediately available to your users without having to write any additional line of code!

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Data exchange using Bluetooth and IrDA

We will also explore how we can transfer the lead details from one device to another directly using both the device's Bluetooth and IrDA (Infrared) capabilities. You will learn how you can efficiently package and compress XML-based data for transmission across these channels.

Capturing handwritten input

When new buyers sign up for a subscription to the game, Tomorrow Inc. needs their signature for record purposes. We can implement signature-capturing functionality using the Smart Device Framework's signature control. The signature will be captured as an image and saved together with the customer record in the database. In Chapters 3 and 6, we will cover more ground on file attachments and how they can be alternatively stored outside the database in the local filesystem. You will also learn of the different options available to the developer to sync files to a remote server.

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Chapter 1

Data synchronization

Data synchronization for the sales force application is a mix of bidirectional (between mobile device and server) and unidirectional synchronization (mobile device to server only). The synchronization process is closely tied to the database systems that we are deploying for the application. For instance, Oracle Lite uses mSync technology while Microsoft SQL Server Compact uses the Microsoft Sync Framework. In Chapter 6, Data Synchronization, you will learn how to set up a mobile device and a server for data sync on these two databases. We will also go through the various approaches available to handle data concurrency and integrity during the sync process.

Dual database support

As part of Tomorrow Inc.'s requirements, we will ensure that our sales force application can support both the Oracle Lite 10g and Microsoft SQL Server Compact mobile databases. These two databases differ considerably in terms of their data types, SQL syntax, and synchronization processes.

Application maintenance and upgrades

As we've covered earlier on in this chapter, one of the biggest disadvantages of a thick client is the deployment process. Any subsequent updates to the application need to be redeployed to all devices. We will mitigate this drawback by building and integrating a network-aware Auto Update service into our sales force application. You will learn how to create a service that can periodically check and download the latest updates from a remote site on its own without the need to cradle the device.

Defining the mobile dashboard application

Our second application, the mobile dashboard, will be used by executive-level decision makers in Tomorrow Inc. on the move. The mobile dashboard will need to pull real-time data off the server over an Internet connection, which is then collated and presented on the dashboard in the form of a graphical chart. New data is periodically pulled down from the server every minute to refresh the chart displays.

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You can see how a smart client model would probably work best in this scenario; a smart client allows you to render the charts you need on the device while keeping data on a remote server. The real-time nature of the data received will also ensure that your charts always display the latest information.

Using stateless web services as a data source With "on the move" scenarios, you can probably expect Internet service to be choppy or simply not available in some areas during travel. We will therefore use stateless web service calls to the remote server to access data in real time. Using stateless connections in our application allows our dashboard to resume from where it left off after an Internet service disruption without having to request the user to perform any additional action (such as a re-login). The mobile dashboard service will appear seamless to the end user. A stateless web service call is a web service call that does not maintain any state information in between calls.

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Chapter 1

Web service calls are also, by default, blocking (synchronous) calls. What this means is that when a call is made to the server to retrieve data, your application will ignore all user input until the data is returned. This is certainly not acceptable, especially on a smart client! In Chapter 10, Building the Dashboard, when we build the dashboard, we will explore how we can make use of the multithreading features of the .NET Compact Framework to create asynchronous web service calls.

Rendering the dashboard

The planned dashboard design will look roughly similar to the following screenshot:

You will create the following charts in this application:

Road show revenue

This line chart sums up the total revenue collected from the road shows on a daily basis. The process of building this chart will introduce the basic drawing tools in the GDI + API that you can use in your application for visual data display.

[ 27 ]


Total monthly sales

In this chart, you will learn how you can make use of the Smart Device Framework's Gauge control to show the total monthly sales amount as a circular gauge chart.

Sales for last three months

Lastly, we will explore how you can make use of the GDI + API to render a bar chart showing the sales figures for the last three months.

Defining the mobile support case application

Our third and last application, the mobile support case application, involves tighter real-time collaboration between the server and the mobile units. We will use the .NET Compact Framework's messaging controls to build a messaging backbone across the server and the connected mobile devices so that Tomorrow Inc. technicians on the field can be instantly alerted when a new task is created in the server. As all job-related data is stored and managed centrally on the remote server, the smart client model would be the best fit for this application. We stop short of using the thin client model because the construction of the messaging backbone will require client-side coding.

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Chapter 1

Building a messaging backbone with MSMQ This application is also unique in that it can be regarded as 'push' technology, whereas the earlier two applications were not. 'Push' technology, similar to the common meme 'push e-mail,' is proactive and means that newly available data is automatically pushed to the mobile device without the mobile device requesting for it.

Part of Tomorrow Inc.'s requirements for this application include instant notification to all mobile device units when a new job is created on the server. MSMQ (Microsoft Message Queuing) is a technology that allows an application to send a message to another application (not necessarily on the same machine) even if the other application is offline. These messages are stored in a queue and delivered when the targeted application resumes operation.

As you start building this application in Chapter 11, Buliding the Support Case System you will learn more about the intricacies of the MSMQ service and how you can write code to send and receive messages using the Messaging APIs.

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Summary

From this chapter we've learned that there are four common client models used in mobile development, each with their own strengths and weaknesses. In this book, we will build three applications that cover the two models that utilize the .NET Compact Framework—thick and smart clients: •

The mobile sales force application is a thick-client application that allows users to key in data offline and to sync it with a remote server at a later time.

•

The mobile dashboard application is a smart-client application that will utilize stateless web services for data retrieval due to the limited availability of its Internet connection.

•

The mobile support case application demonstrates how a common messaging backbone can be built on top of the MSMQ framework to provide instant notifications to mobile devices.

Your journey through this book will also ultimately walk you through three important aspects of mobile application development: •

Learning the various methods of data transmission between the mobile device and a remote server and between mobile devices themselves

•

Learning the various ways to integrate Windows mobile and the device itself to provide an interactive and seamless solution

•

Designing an adaptable three-tier and MVC-based solution that makes future maintenance of the application easier.

With this overview, we have enough context to begin building the application. We will start by creating the data layer for the mobile sales force application in the next chapter.

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Building the Data Tier The data tier handles all transactions between the database and the logic tier. In this chapter, we will explore how we can build a plugin-based data tier for the CRMLive. NET mobile sales force application. A plugin-based data tier has the benefit of not having to recompile the entire application when an underlying database change needs to be done. It also serves to further increase the decoupling of the data tier from the adjacent logic tier. Different database support is provided through the distribution of small DLL (Dynamic Link Library) plugin files, which can be installed or removed by the end user depending on his or her needs. By the end of this chapter, you will have learned: •

How to build an adaptable plugin-based data tier

•

How to set up Oracle Lite and SQL Server CE on the mobile device

•

The differences between Oracle Lite 10g and SQL Server CE 3.5

•

How to use interfaces to access Oracle Lite and SQL Server CE through the same set of method calls

•

How to connect, read, and write data to and from Oracle Lite and SQL Server CE using ADO.NET DataSets

Designing the data tier

As best practice, the logic tier only needs to describe at a higher level of abstraction, what it needs, and the data tier will do the work of retrieving the data from the database. Enter the IDataLibPlugin interface. This interface provides a set of method calls that must be implemented by both the SQL Server CE and Oracle Lite plugins. The logic tier will not need to concern itself with the low-level implementation for either database. It will make all its data requests through this interface.

Building the Data Tier

The classes and their relationships in the data tier can be summarized in the following class diagram. In this chapter, you will create two forms: PluginsSetup and ConfigurePlugin that lets the user manage the list of plugins in the sales force application. These forms utilize a global class called GlobalArea (which essentially contains a single instance of the PluginManager class). The PluginManager class contains a PluginCollection object, which is a list of all the plugins installed on the device. It also contains functions to add or remove plugins, but more importantly, to save and load this whole list to and from disk.

SQL Server CE 3.5 versus Oracle Lite 10g

In a thick client application, an important factor in deciding which mobile database to use depends on what you have installed on the server as your enterprise database. Data synchronization between the device and the enterprise database is usually a job that you want to leave entirely to the database engine. For instance, it doesn't make sense to use Oracle Lite on your mobile device when your enterprise database is SQL Server because they would not be able to sync between themselves. [ 32 ]

Chapter 2

In the sales force application, you will be implementing both databases. There are a few differences between these two databases, which you might be interested to know. They are listed in the following table: SQL Server CE

Oracle Lite

Microsoft provides the Microsoft Sync Framework (with SQL Server 2008) that allows you to sync a SQL Server CE database with any different database (any ADO.NET accessible database)

Oracle Lite syncs only with an Oracle database through the Oracle Mobile Server

SQL Server CE supports IDENTITY columns

Oracle Lite supports the use of SEQUENCES to implement running counters

Mobile database footprint is roughly half the size of Oracle Lite (~2.5MB)

Has a bigger mobile database footprint (~5MB)

Provides GUI-based db management tool to create and manage table schemas

Provides a GUI-based db management tool, but table schema creation/manipulation has to be done through SQL

Does not support database views

Supports database views

One important consideration to note is that both Microsoft SQL Server CE and Oracle Lite do not provide support for stored procedures. Your mobile applications can, however, use parameterized queries for data access.

Connecting the Windows Mobile emulator to ActiveSync

The Windows Mobile SDK provides an emulator kit that lets you test your mobile applications on a PC without the need for a real device. Although you can test your applications on a real mobile device connected to your PC, chances are you will most likely use the emulator at one point or another out of convenience. When using this emulator, you will most likely need to transfer files between your development machine and the emulator. Before you can do this, you must first establish an ActiveSync connection between the two by simulating a cradle on the emulated device. To do this, you must have ActiveSync 4.5 (for Windows XP users) or Windows Mobile Device Center (for Windows Vista users) installed on the development machine.

[ 33 ]


Open Windows Mobile Device Center and click on Connection Settings under Mobile Device Settings. Ensure that the DMA option has been selected under Allow connections to one of the following.

After saving these settings, run the emulator either by running your project in Debug mode or by navigating to Tools | Connect to device in your Visual Studio IDE. After your emulator is up and running, navigate to Tools | Device Emulator Manager. You will be prompted with a window displaying a list of all device emulators registered on your system. Locate the active emulator (the one with an icon of a green arrow next to it). Right-click on this emulator and select the Cradle action from the pop-up menu that appears.

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Chapter 2

Upon doing so, your emulator will begin to connect to ActiveSync/Mobile Device Center. Once it has connected successfully, your ActiveSync/Mobile Device Center will display a Connected message. You will now find that you can access the filesystem of the emulated device via Windows Explorer on your development machine.

Setting up SQL Server Compact 3.5

Now that you have connected the emulator to your development machine, you will need to install SQL Server CE on both your development machine and the mobile device.

Installing SQL Server CE on the development machine

The SQL Server Compact 3.5 SP1 package contains all the .cab files we need for deployment to the various supported devices and operating systems. To install SQL Server Compact 3.5 on your development machine, follow these instructions: •

Download SQL Server Compact 3.5 Service Pack 1 for Windows Mobile from the following URL: http://www.microsoft.com/Sqlserver/2005/en/us/compact-downloads.aspx

The other downloads on the web page are not relevant to this chapter, so we will leave them out for now. •

Run the downloaded file on your development machine and follow through the setup wizard to the end.

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Installing SQL Server CE on the Pocket PC device.

Now that we have installed SQL Server CE on the development machine, we will try to get a copy of the database engine running on the Pocket PC device. There are a two ways to get Microsoft SQL Server Compact installed on the Pocket PC device: •

MS Visual Studio automated deployment: If you have added a reference to SQL Server CE in your project, the SQL Server CE database engine will be automatically deployed to the mobile device when you run or debug your application from inside Microsoft Visual Studio.

•

Manual deployment: We can also manually copy the relevant SQL Server CE .cab files to the mobile device and deploy it directly from the device.

We will explore the second approach in the later section. The installation of SQL Server CE earlier creates a bunch of .cab files in the following location: \Program Files\Microsoft SQL Server Compact Edition\v3.5\Devices\ wce500\armv4i

Let's take a look at the SQL Server CE .cab files in detail. You will notice that there are generally three types of files: Feature sqlce.device.platform.processor

Description

sqlce.repl.device.platform.processor

This .cab file contains SQL Server CE replication functionality

sqlce.dev.language.device.platform. processor

This .cab file contains the developer tools such as the Query Analyzer 3.5

This .cab file contains the SQL Server CE database engine

To manually install these .cab files to your mobile device, follow these instructions: 1. Copy the three files (sqlce.dev.*.cab, sqlce.repl.*.cab, and sqlce.*.cab) that correspond to your target device, operating system, and processor to any folder on the mobile device manually. (Example: For English-based Windows Mobile 5/6 Pocket PC devices, the file extension would be ENU.ppc.wce5.armv4i)

[ 36 ]

Chapter 2

2. Run the sqlce.*.cab file from your mobile device or device emulator first, and the other two .cab files after that in any order. 3. In each installation a …successfully installed message will be displayed if the setup did not encounter any problems. SQL Server CE 3.1 and Windows Mobile 6 It is interesting to note that Windows Mobile 6 devices and emulators have the SQL Server CE 3.1 database engine already prebuilt into their ROM. This means that a manual database engine install will not be required if you are building your applications on top of SQL Server CE 3.1. SQL Server CE 3.1 has some limitations, mainly in that it cannot utilize the rich data features in Microsoft Visual Studio 2008. These rich data features include the Visual Database Tools, Data Source Configuration Wizard, and Data Designer Tools. The examples in this book will all be based on SQL Server CE 3.5.

Setting up Oracle Lite 10g

The Oracle Lite 10g database is Oracle's equivalent to Microsoft's SQL Server CE. It is provided free of charge, and can also sync with a standard Oracle database server. The Oracle Lite database consists of two main components: Mobile Server and the Mobile Development Kit.

Installing Oracle Lite 10g on the development machine To install Oracle Mobile server on your development machine, simply follow these instructions:

1. Download Oracle Database Lite 10g Release 3 (10.3.0.2.0) for Microsoft Windows (32-bit) from the following URL: http://www.oracle.com/technology/software/products/lite/ index.html.

2. Extract the contents of the downloaded file into any folder on your development machine and run the setup. 3. Install only the Oracle Mobile Development Kit. We will not need to install the Mobile Server at the moment (as this will require the installation of the full Oracle database). [ 37 ]


Installing Oracle Lite 10g on the Pocket PC device

You will find two .cab files if you navigate to the folder below (where ORAHOME is the root location where you've installed Oracle Lite): \ORAHOME\Mobile\Sdk\wince\ppc60\cabfiles Feature

Description

olite.language.device.processor

This .cab file contains the main Oracle Lite 10g database engine

tools.language.device.processor

This .cab file contains the developer tools for Oracle Lite 10g such as Msql

There are two ways to get Oracle Lite 10g installed on the mobile device: Via Mobile Server: Oracle Mobile Server provides a way to invoke the setup of the Oracle database engine on the mobile device over ActiveSync. We will revisit Mobile Server in detail when we discuss data synchronization in Chapter 6, Data Synchronization. • Manual deployment: We can also manually copy the olite.language.device.processor.cab file and the tools.language.device.processor.cab file to the mobile device and deploy it directly from the device. •

We will use the second method of the previous section to install the .cab file to your mobile device: 1. Copy the olite.language.device.processor.cab and the tools.language.device.processor.cab files that correspond to your target language, device, and processor to any folder on the mobile device manually. 2. Run the .cab file from your mobile device or device emulator. 3. A …successfully installed message will be displayed if the setup did not encounter any problems.

Building the data tier

Now that you have both databases set up on your mobile device, you're ready to build the data tier. Let's take a first-hand look at the various Visual Studio projects you are going to build. There are four different Smart Device projects (all hosted within the same Visual Studio solution). [ 38 ]

Chapter 2

Let's take a look at an overview of these projects: Project name

Description

CRMLiveFramework

This is a light-weight Class Library project that contains the basic classes (PluginManager, PluginCollection, IDataLibPlugin) needed throughout the other projects. It is expected to be referenced by almost all the other projects.

SalesForceApp

This is the main Application project—the sales force application itself. It will hold all the forms (UI) and logic for the sales force application. For this chapter, we will only build the forms related to setting up and configuring the various database plugins.

SQLServerPlugin

This is the actual SQL Server CE plugin. It is a Class Library project that contains all the functions necessary to process SQL Server CE database access requests.

OracleLitePlugin

This is the Oracle Lite plugin. Just like the SQLServer plugin, it is a Class Library project that contains all the functions needed for Oracle Lite database access requests.

Building the CRMLiveFramework project

This project is meant to be a lightweight Class Library project (that, when compiled, produces a .DLL file). It contains all the basic, common, and shared classes that will need to be used throughout the Sales Force solution. It is therefore expected to be referenced by all other projects. You will be adding more classes and functionality to the CRMLiveFramework project as you progress through the book. In this chapter though, it will only contain the following items: Item name

Description

IDataLibPlugin interface

The IDataLibPlugin interface provides the rest of the sales force application with a consistent set of methods to retrieve data from the SQL Server CE and Oracle Lite databases without having to worry about its underlying implementation.

PluginCollection class

This class inherits from the System.Collections.Hashtable class. It is used to hold a list of plugin objects that implement the IDataLibPlugin interface.

PluginManager class

This class contains the functions to install and remove plugins from the framework. It will also handle the persisting of plugin information to disk (in the form of XML) and vice versa.

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Let's start by launching the Visual Studio application and creating a new Smart Device project. Enter CRMLiveFramework as the name of this project and click OK to proceed. You will be prompted with another window as shown in the following screenshot. Do ensure that you have chosen the Class Library project type, Windows Mobile 6 Professional SDK as the Target platform, and the .NET Compact Framework Version 3.5 as the target framework before continuing.

As a last step, you need to change the namespace of the project to a more consistent one. To do this, navigate to the Project | CRMLiveFramework Properties menu item and launch it. Change the Root namespace value to CRMLive. We will establish CRMLive as the namespace for all the projects in the Sales Force solution.

After this is done, you have created your very first Smart Device project! We will proceed to create some classes for this project in the next section.

Defining the IDataLibPlugin interface

At the heart of the data tier lies the IDataLibPlugin interface. It contains a set of method definitions that define how the sales force application communicates with the SQL Server CE and Oracle Lite databases.

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Chapter 2

An interface is a collection of method definitions (without the implementation). A class that implements an interface has to provide implementations for each and every defined method of the interface. Interfaces are great for defining a consistent set of behavior that different classes have to provide, but leaves the details of the implementation to these classes.

Add a new Interface item to your CRMLiveFramework project by launching the Project | Add New Item menu item and choosing Interface as the item type. Name your Interface IDataLibPlugin when prompted. Let us take a look at the various methods we will define in this interface: public interface IDataLibPlugin { //========================================================= //The following properties are required for all plugins //so we define them in the interface //========================================================= string Datasource { get; set; } string PluginPath { get; set; } bool Active { get; set; } string PluginFullName { get; } //========================================================= //This method opens a connection to the database designated //by the Datasource property //========================================================= bool ConnectDatabase(); //=========================================================

[ 41 ]

Building the Data Tier //This method closes the connection opened via //ConnectDatabase() //========================================================= bool DisconnectDatabase(); //========================================================= //The CreateSalesForceDatabase() method defines a function //that generates an entirely new and empty Sales Force //database //========================================================= bool CreateSalesForceDatabase(); //========================================================= //The GetAccountDetails() method defines a function that //takes in an AccountGUID value and returns a Dataset //object containing the full details of the account //========================================================= DataSet GetAccountDetails(Guid AccountGUID); //========================================================= //The SetAccountDetails() method defines a function that //takes in a Dataset object (containing the updated account //details). The function must then write the updated //details to the underlying database //========================================================= bool SetAccountDetails(Guid AccountGUID, DataSet Account); //========================================================= //The RemoveAccount() method removes an account record and //all its related child records //========================================================= bool RemoveAccount(Guid AccountGUID); //========================================================= //The AccountExists checks if an account with the same //first name and last name already exists //========================================================= bool AccountExists(string FirstName, string LastName, Guid AccountGUID); //========================================================= //The ChangeAccountType() method defines a function that //changes the type of an account between a Lead, //Opportunity and Customer //========================================================= bool ChangeAccountType(Guid AccountGUID, int Type); [ 42 ]

Chapter 2 //========================================================= //The GetProductList() method retrieves the full list of //records from the Products table as a Dataset //========================================================= DataSet GetProductList(); //========================================================= //The GUIDToNative() method converts a .NET System.GUID //object into the database's native data type used to store //GUID values //========================================================= object GUIDToNative(Guid AccountGUID); //========================================================= //The NativeToGUID() method does the opposite – it converts //the database's native data type for GUID into a .NET //System.GUID object //========================================================= Guid NativeToGUID(object AccountGUID); }

What goes in an interface? As a rule of thumb, two functions that achieve the same output but do so in different ways are good candidates to include in an interface. For instance, consider the GetAccountDetails() method we used in the previous section. We know that regardless of the database used, if we pass in the GUID of an account, it will return a Dataset containing the matching account details. How this data retrieval is done in SQL Server CE and Oracle Lite, however, is entirely different; SQL Server CE uses the SqlCeCommand class, whereas Oracle Lite uses the OracleCommand class.

With that done, you will now proceed to build the Plugin Manager UI.

Building the Plugin Manager UI

The SalesForceApp project contains forms, which would usually be regarded as part of the presentation and logic-level tier, and so it may seem a little strange that we're covering this in a data tier chapter. The forms that you will be particularly looking at, however, have a lot to do with the managing, installing, and registering of the database plugins that you have created, and so constitute an important part of the data tier. Let us take a quick look at what these forms are supposed to do.

[ 43 ]


An overview

When we first launch our SalesForceApp project, we will encounter the form as in the following screenshot. This form allows the user to install or remove a plugin. For instance, if the user wanted to have Oracle Lite and SQL Server CE support on his mobile device, he or she would have to install both the OracleLitePlugin and SQLServerPlugin plugins in this window.

When a user clicks on the New plugin button, this will open the window shown in the following screenshot. The user will have to key in the path of the plugin DLL (or browse for the file using the button next to the field). Upon selecting a plugin that conforms to the IDataLibPlugin interface, the plugin's full name will be shown in the same window. The user would then be required to specify the connection settings to an existing database in the Plugin datasource field. When installing a plugin for the first time, the sales force database does not exist. A Create now button will, therefore, be provided to allow the user to generate a new sales force database (together with its schema) on the mobile device. After that, it will automatically point the Plugin datasource field to this newly created database. When this has been done, the user will need to click on the Save button to finally install this plugin.

[ 44 ]

Chapter 2

Although the user can add multiple database plugins to his or her mobile device, only one plugin can be active at any one time. The user can select the active plugin by placing a tick in the checkbox next to the plugin, as shown in the following screenshot:

Before you start to create the forms shown previously, you will first need to create a couple of classes—a PluginCollection class to store this list of plugins and a PluginManager class to manage that list. Both classes will be created in the CRMLiveFramework project.

[ 45 ]


Implementing the PluginCollection class

The PluginCollection is a small class that inherits from the System.Collections. HashTable object. The purpose of this class is to maintain a list of IDataLibPlugin objects. You need to inherit from the System.Collections.HashTable class because it allows you to refer to a stored object in its list using the plugin's full name. Add a new class to the CRMLiveFramework project and name it PluginCollection: public class PluginCollection : Hashtable { //========================================================= //This Add() function allows us to add a plugin object //to the collection, using the plugin name as the key //========================================================= public IDataLibPlugin Add(IDataLibPlugin PluginObject) { if (base.Contains(PluginObject.PluginFullName) == false) { base.Add(PluginObject.PluginFullName, PluginObject); return PluginObject; } else { return null; } } }

Implementing the PluginManager class

The PluginManager class will make use of a single instance of the PluginCollection object to hold a list of plugins that are installed on the framework. It will also contain functions that handle the installation of new plugins or the removing of existing ones. More importantly, this class will also need to be able to persist the PluginCollection to disk and to also load it back from disk. This class is expected to use .NET reflection and XML services, so you will need to import the references to these libraries. Let's take a look at the following skeleton code of this class: using System.Reflection; using System.Xml; public class PluginManager { [ 46 ]

Chapter 2 private PluginCollection _plugins; //========================================================= //This function simply returns the _plugins collection //========================================================= public PluginCollection GetPluginsList() { return _plugins; } //========================================================= //This function accepts a plugin name and returns the //corresponding plugin object from the _plugins collection //========================================================= public IDataLibPlugin GetPluginObject(string PluginName) { return _plugins.Item(PluginName); } }

Let's create an AddPlugin function that will load a DLL given its path, and add an instance of the plugin to the PluginCollection object. The AddPlugin function takes in the full path of the DLL plugin file and the plugin data source (connection string). You will use .NET reflection to dynamically load the DLL and create an instance of the plugin class. public IDataLibPlugin AddPlugin(string PluginPath, string PluginDatasource, bool Active) { Assembly _AssemblyObject; IDataLibPlugin _PluginObject; _AssemblyObject = Assembly.LoadFrom(PluginPath); _PluginObject = (CRMLive.IDataLibPlugin) (_AssemblyObject.CreateInstance("CRMLive.PluginClass")); _PluginObject.Datasource = PluginDatasource; _PluginObject.PluginPath = PluginPath; _PluginObject.Active = Active; _plugins.Add(_PluginObject); return _PluginObject; }

The Assembly class is part of the System.Reflection namespace. It provides the functions that allow you to load and instantiate a class contained in an external library file.

[ 47 ]


Let's also create the opposite function, the RemovePlugin function. Its job is to simply remove the desired plugin from the PluginCollection object: public void RemovePlugin(string PluginName) { _plugins.Remove(PluginName); }

Your PluginManager class will also need to persist the PluginCollection to disk. You will create a SaveAllPlugins function that serializes the list of plugins in PluginCollection into XML and then saves it to the plugins.xml file. For this purpose, you will use the System.Xml library. The three important attributes of each plugin that you need to save to disk are: •

Plugin path

•

Data source

•

Status of the plugin (whether it is active or not)

public void SaveAllPlugins() { int _counter = 0; IDataLibPlugin _pluginObject; string _activePluginName = ""; XmlDocument _xmlDoc; XmlElement _xmlRoot; XmlElement _xmlPlugin; _xmlDoc = new XmlDocument(); _xmlRoot = _xmlDoc.CreateElement("Root"); _xmlDoc.AppendChild(_xmlRoot); foreach (IDataLibPlugin _pluginObject in _plugins.Values) { _xmlPlugin = _xmlDoc.CreateElement("Plugin"); _xmlPlugin.SetAttribute("PluginPath", _pluginObject.PluginPath); _xmlPlugin.SetAttribute("Datasource", _pluginObject.Datasource); _xmlPlugin.SetAttribute("Active", (string)_pluginObject.Active); _xmlRoot.AppendChild(_xmlPlugin); } _xmlDoc.Save("plugins.xml"); } [ 48 ]

Chapter 2

Now that you can save the collection to disk, you will need to create a LoadAllPlugins function that does the opposite task. It reads XML from the plugins.xml file and reconstructs the PluginCollection object using stored plugin information: public void LoadAllPlugins() { string _pluginPath = null; string _pluginDatasource = null; bool _active = false; int _counter = 0; XmlDocument _xmlDoc; XmlElement _xmlPlugin; XmlElement _xmlRoot; _plugins = new PluginCollection(); _xmlDoc = new XmlDocument(); try { _xmlDoc.Load("plugins.xml"); } catch (Exception ex) { return; } _xmlRoot = (System.Xml.XmlElement) _xmlDoc.ChildNodes.Item(0); for (_counter = 0; _counter = TotalRecords) { _pageRecordCount = TotalRecords - ((PageNumber - 1) * PageSize); } else { _pageRecordCount = PageSize; } _command = _globalConnection.CreateCommand(); _whereclause = BuildWhereClause(SearchParam); _command.CommandText = "SELECT * FROM (SELECT TOP(" + _pageRecordCount + ") * FROM (SELECT TOP(" + _initialSelectSize + ") * FROM Accounts " + _whereclause + " ORDER BY " + _sortColumn + " " + _sortDirection + ", AccountGUID DESC) AS [mytable] ORDER BY " + _sortColumn + " " + _sortOppDirection + ", AccountGUID ASC) AS [ 162 ]

Chapter 4 [mytable2] ORDER BY " + _sortColumn + " " + _sortDirection + ",AccountGUID DESC"; _adapter = new SqlCeDataAdapter(_command); _adapter.Fill(_resultSet, "Accounts"); _adapter.Dispose(); _command.Dispose(); return _resultSet; }

Let us now take a look at how you can do the equivalent in Oracle Lite.

Creating the parameterized search query in Oracle Lite

The GetAccountsByParameters() function is similar to the page-retrieving function (GetAccountsByType()) you've created for Oracle Lite in the previous chapter, with the only changes required highlighted in the following code snippet: public DataSet GetAccountsByParameters(AccountSearchParameters SearchParam, int TotalRecords, int PageNumber, int PageSize, string SortColumn, GlobalVariables.SortingOrder SortDirection) { . . . _whereClause = BuildWhereClause(SearchParam); _command.CommandText = "SELECT ROWNUM, TO_CHAR(AccountGUID) AS AccountGUID, AccountType, DateCreated, Firstname, Lastname, Status, Reception, Source, ResPhoneNo, MobPhoneNo, EmailAddress, Street, City, State, Zipcode, Country, Website, InterestedProds FROM Accounts " + _whereClause + " AND ROWNUM>=" + _lowerlimit + " AND ROWNUM0"; } } if (_SubWhereClause.Length > 0) { //As we are still inside a loop that runs through //phrases separated by the NOT operator, //we reattach each formatted portion together //using the NOT operator _WhereClause += ((_WhereClause.Length > 0) ? " AND " : "") + (_counter > 0 ? "NOT " : "") + _SubWhereClause; } } } if (_WhereClause.Length > 0) { //If the WHERE clause is not empty, we append the //'WHERE' SQL keyword at the front _WhereClause = "WHERE " + _WhereClause; } return _WhereClause; }

As an example, passing the search phrase "Medical OR Certificate NOT Clinic" through the function above will produce the following: WHERE CHARINDEX('Medical',Keywords)>0 OR CHARINDEX('Certificate',Keywo rds)>0 AND NOT CHARINDEX('Clinic',Keywords)>0

As you've seen in the brief walk-through earlier on in this chapter, the full-text search results are displayed differently. Instead of the usual DataGrid listing, we choose to display in similar fashion to online search engines, which is to display each search result item with a text summary at the bottom.

[ 178 ]

Chapter 4

The text summary displayed isn't just a random snippet of text from the Keywords field. It must contain at least one of the search phrase keywords typed in by the user for the display to be meaningful. These keywords are highlighted in bold in the text summary. To retrieve these text summaries, you can use another T-SQL function available in SQL Server CE—the SUBSTRING(expression, starting_position, length) function. This function simply extracts a chunk of text (with a specified length) from a specified field and starting position. Hence, assuming you have the following data: TABLE [AccountFiles] --------------------------------------Keywords --------------------------------------This Medical Certificate proves that...

If you combine the CHARINDEX() function with the SUBSTRING() function in the following manner: SELECT SUBSTRING(Keywords,CHARINDEX('Medical',Keywords),12) FROM AccountFiles

You will get the following result: Medical Cert

You can use these two functions to extract the first chunk of text that contains the search phrase keywords. Keeping in mind that a search phrase may consist of more than one set of keywords (attached via the OR operator), you need to call these two functions for every OR keyword in the search phrase. The search phrase Medical OR Certificate NOT Clinic will hence translate to the following: SELECT SUBSTRING(Keywords,CHARINDEX('Medical',Keywords),100) AS [TextSummary1], SUBSTRING(Keywords,CHARINDEX('Certificate',Keywords), 100) AS [TextSummary2] FROM AccountFiles

Let's write some code to do this translation: private string BuildSelectClause(string SearchPhrase) { int _counter; int _counter2 = 1; string[] _NOTPhrases; string[] _ORPhrases; string _ActivePhrase; string _ORPhrase;

[ 179 ]

Building Search Functionality string _SelectClause; _SelectClause = ""; //Split the search phrase at the NOT operator _NOTPhrases = Regex.Split(SearchPhrase, "\\bNOT\\b", RegexOptions.IgnoreCase); //Everything after the NOT is not needed. We only need the //part on the left of the NOT operator _ActivePhrase = _NOTPhrases[0].Trim(); if (_ActivePhrase.Length > 0) { //Split the phrase using the OR operator _ORPhrases = Regex.Split(_ActivePhrase, "\\bOR\\b", RegexOptions.IgnoreCase); for (_counter = 0; _counter 0) { //For each OR operator, we call the SUBSTRING and //CHARINDEX functions. Take note that we deduct 30 //characters from the starting point so that the //keyword does not appear exactly as the first //word in the text summary. This is purely for //aesthetic value _SelectClause += ((_SelectClause.Length > 0) ? "," : "") + "SUBSTRING(Keywords,CHARINDEX(\'" + _ORPhrase + "\',Keywords)-30,120) AS [TextSummary" + _counter2.ToString() + "]"; _counter2++; } } } if (_SelectClause.Length == 0) { //If no keyword was specified in the search phrase, we //simply return the first 120 characters of the text [ 180 ]

Chapter 4 _SelectClause = "SUBSTRING(Keywords,0,120) AS TextSummary1"; } return _SelectClause; }

Now that you've created this function, you can proceed to build the full-text search queries. The full-text search function is expected to return paged data, so this means that you will again implement two functions—one to return the search result count and another to return paged data. The code is very similar to the previous ones you've done. The code for the count function follows. It makes use of the BuildWhereClause() function you've created earlier. public int GetAccountFilesCountBySearchPhrase(string SearchPhrase) { . . . _whereClause = BuildWhereClause(SearchPhrase); _command.CommandText = "SELECT COUNT(*) AS RecordCount FROM AccountFiles " + _whereClause; . . . }

The code to retrieve the paged data follows next. It makes use of both the BuildWhereClause() and BuildSelectClause() functions you've created. public DataSet GetAccountFilesBySearchPhrase(string SearchPhrase, int TotalRecords, int PageNumber, int PageSize, string SortColumn, GlobalVariables.SortingOrder SortDirection) { . . . _command = _globalConnection.CreateCommand(); _whereClause = BuildWhereClause(SearchPhrase); _textSummaryClause = BuildSelectClause(SearchPhrase); _command.CommandText = "SELECT * FROM (SELECT TOP(" + _pageRecordCount + ") * FROM (SELECT TOP(" + _initialSelectSize + ") b.FirstName, b.LastName, b.AccountType, a.AccountGUID,a.AttachmentID, [ 181 ]

Building Search Functionality a.AttachmentName, a.AttachmentSize, a.Attachment," + _textSummaryClause + " FROM AccountFiles a LEFT JOIN Accounts b ON a.AccountGUID=b.AccountGUID " + _whereClause + " ORDER BY " + _sortColumn + " " + _sortDirection + ", AttachmentID DESC) AS [mytable] ORDER BY " + _sortColumn + " " + _sortOppDirection + ", AttachmentID ASC) AS [mytable2] ORDER BY " + _sortColumn + " " + _sortDirection + ",AttachmentID DESC"; . . . }

Let's now take a look at the equivalent for Oracle Lite.

Creating the full-text search query for Oracle Lite

In Oracle Lite, the equivalent of the CHARINDEX() and SUBSTR() functions are the INSTR() and SUBSTR() functions. Unfortunately, these two functions can only work on the CHAR or VARCHAR data types and not on the LONG or CLOB data types. This presents a problem for us. CHAR or VARCHAR data types are small by nature (they can only fit up to a maximum of 4,096 bytes), whereas the LONG and CLOB data types allow us to store data up to roughly 2 gigabytes in size. If we don't use the LONG and CLOB data types, we cannot

store keywords of any significant size. (A long text document, for instance, can easily contain thousands of unique words).

So, how do we use the CLOB data type to store keywords and yet retain the ability to perform a full-text search? Fortunately, Oracle Lite allows you to use the SQL LIKE operator to search for an expression within a CLOB field. We will use this in place of the CHARINDEX() function. However, there is no other equivalent workaround to obtain the location of a phrase in a CLOB field. So, in other words, we can retrieve a list of files matching the search phrase but we can't determine where the search phrase occurs in the file.

[ 182 ]

Chapter 4

Hence, for the text summary that is displayed with the search results, we will simply display the first 120 bytes of the text in the matching file. Let's take a look at the BuildWhereClause() function for Oracle Lite. The differences in the Oracle Lite code are highlighted in the following code: private string BuildWhereClause(string SearchPhrase) { int _counter; int _counter2; string[] _NOTPhrases; string[] _ORPhrases; string _NOTPhrase; string _ORPhrase; string _WhereClause; string _SubWhereClause; _WhereClause = ""; //Split the search phrase using the NOT operator _NOTPhrases = Regex.Split(SearchPhrase, "\\bNOT\\b", RegexOptions.IgnoreCase); for (_counter = 0; _counter 0) { //Split the phrase further using the OR operator _ORPhrases = Regex.Split(_NOTPhrase, "\\bOR\\b", RegexOptions.IgnoreCase); _SubWhereClause = ""; for (_counter2 = 0; _counter2 0) { //We use the LIKE operator to do the comparison _SubWhereClause += ((_SubWhereClause.Length > 0) ? " OR " : "") + "a.Keywords LIKE \'%" + _ORPhrase + "%\'"; } } if (_SubWhereClause.Length > 0) { [ 183 ]

Building Search Functionality _WhereClause += ((_WhereClause.Length > 0) ? " AND " : "") + (_counter > 0 ? "NOT " : "") +_SubWhereClause; } } } if (_WhereClause.Length > 0) { _WhereClause = "WHERE " + _WhereClause; } return _WhereClause; }

The GetAccountFilesBySearchPhrase() function in Oracle is similar to the standard paged data retrieval function. The main differences are shown below. For Oracle Lite, you do not have to create a corresponding BuildSelectClause() function. It will always return the first 120 characters in the matching file. SQL joins in Oracle Lite Take note that Oracle Lite does not support the ANSI join syntax (a LEFT JOIN b). It uses the ODBC join syntax instead. ({OJ a LEFT JOIN b}). public DataSet GetAccountFilesBySearchPhrase(string SearchPhrase, int TotalRecords, int PageNumber, int PageSize, string SortColumn, GlobalVariables.SortingOrder SortDirection) { . . . _whereClause = BuildWhereClause(SearchPhrase); _command.CommandText = "SELECT ROWNUM, TO_CHAR(a.AccountGUID) AS AccountGUID, b.FirstName, b.LastName, b.AccountType, a.AttachmentID, a.AttachmentName, a.AttachmentSize, a.Attachment,SUBSTR(CAST(a.Keywords AS VARCHAR(120)),1,120) AS TextSummary1 FROM {OJ AccountFiles a LEFT JOIN Accounts b ON a.AccountGUID=b.AccountGUID} " + _whereClause + ((_whereClause.Length > 0) ? " AND " : " WHERE ") + " ROWNUM>=" + _lowerlimit + " AND ROWNUM @sync_last_received_anchor AND [CreationDate] @sync_last_received_anchor AND a.[CreationDate]

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