The dBASE Book Developing Windows Applications With dBASE PLUS Ken Mayer Second Edition The dBASE Book Developing Windows Applications With dBASE PLUS by Ken Mayer All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the author, except for the inclusion of brief quotations in a review. Copyright © 2005, 2007 by Kenneth (Ken) J. Mayer ISBN: 1-4288-7448-9 (sc) print 978-0-9812906-4-5 (electronic pdf file) First Published by AuthorHouse 5/1/2007 Electronic version published by Freedom Graphics Press, Lytton, BC, Canada V0K 1Z0 on 6/26/2010 First Printing, 2005; Second Printing, 2007 Printed in the United States of America Trademark and Copyright acknowledgments: Visual dBASE, dBASE, dBASE PLUS, dQuery and variations of these product names and words are registered trademarks of dataBased Intelligence, Inc. Borland Database Engine, BDE, Paradox, InterBase and Delphi are registered trademarks of Borland International, Inc. Microsoft, Windows XP (and all other forms of the names of the Windows operating system), Word, Excel, FoxPro are registered trademarks of Microsoft Corporation. Quicken is a registered trademark of Intuit, Inc. Inno Setup is copyrighted to Jordan Russel and Martijn Laan Apache is copyrighted to the Apache Software Foundation No attempt has been made to designate as trademarks or service marks all personal computer words or terms in which proprietary rights might exist. The inclusion, exclusion or definition of a word or term is not intended to affect, or express any judgement on, the validity or legal status of any proprietary right which may be claimed in that word or term. Disclaimer The author and publisher have used their best efforts in preparing this book, and the programs contained herein. However, the author and publisher make no warranties of any kind, express or implied, with regard to the documentation or programs contained in this book, and specifically disclaim without any limitations, any implied warranties of merchantability and fitness for a particular purpose with respect to program listings in the book and/or the techniques described in the book. In no event shall the author or publisher be responsible or liable for any loss or profit or any other commercial damages, including but not limited to special, incidental, consequential or any other damages in connection with or arising out of furnishing, performance, or use of this book or the programs. Table of Contents Table of Contents About the Author ............................................................................ 1 Acknowledgments and Thanks ..................................................... 3 Introduction ..................................................................................... 5 Part I - Getting Started ................................................................... 7 Chapter 1 - Setup and Parts of the Environment ......................... 9 dQuery – the Startup Program ........................................................................... 9 Some Basic Setup .............................................................................................. 9 The dBASE Desktop......................................................................................... 14 The Title Bar .........................................................................................................................14 The Menu Bar ......................................................................................................................15 The Tool Bar .........................................................................................................................15 The Navigator Window .........................................................................................................15 The Command Window .......................................................................................................16 The Status Bar .....................................................................................................................16 Important Tools in dBASE PLUS ...................................................................... 17 Speed Menus .......................................................................................................................17 Getting Help .........................................................................................................................17 Using the Knowledgebase ...................................................................................................19 Windows Vista .................................................................................................. 19 Part II - Data................................................................................... 21 Chapter 2 - Table Types ............................................................... 23 Should I Change the Table Level? .................................................................... 23 Terminology ...................................................................................................... 24 The dBF Field Types ........................................................................................ 24 Field Properties ....................................................................................................................25 Null Values ...........................................................................................................................26 Field Names .........................................................................................................................27 Table Language Drivers .......................................................................................................27 Indexes ................................................................................................................................28 Using BLOB Fields ...............................................................................................................30 DBF Table Limits ..................................................................................................................30 Table Design Guidelines ................................................................................... 30 Identify the Type of Information You Need to Store .............................................................31 Break the Information Down ................................................................................................31 Determine The Relationships Among the Tables .................................................................31 Making it Possible to “Upsize” to Other Platforms ............................................ 33 v Table of Contents Designing Your Tables and Application Appropriately ..........................................................33 Chapter 3 - SQL - A Different Language ..................................... 35 What is SQL, and Why Is It Important? ............................................................ 35 Calculated Fields .............................................................................................. 39 SQL Joins ......................................................................................................... 40 The WHERE Clause ......................................................................................... 40 Read Only Queries ........................................................................................... 40 Other Useful Local SQL Commands ................................................................ 41 Creating a table ....................................................................................................................41 Add/Remove Fields ..............................................................................................................41 Deleting a Table ...................................................................................................................41 Renaming A Table ................................................................................................................42 Creating an Index Tag ..........................................................................................................42 Deleting an Index Tag ..........................................................................................................42 Adding Data to a Table .........................................................................................................42 Update a Set of Data ...........................................................................................................42 Chapter 4 - Connecting to SQL and Local Databases .............. 45 What Is SQL Data, versus dBASE or “Local” Tables? ...................................... 45 Database Aliases .................................................................................................................45 Making the Connection ..................................................................................... 46 Start the Data Engine ...........................................................................................................46 Create the Database Alias ...................................................................................................47 Start dBASE .........................................................................................................................48