C Database Toolchest

396 Pages·1996·89.667 MB·English

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Database Management
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IDatabase Toolchest™
Database Management
Libraries and Tools for C & c++
Copyright © 1996 by Mix Software, Inc.
All Rights Reserved
Copyright © 1996 by Mix Software, Inc.
All rights reserved. No part ofthis book shall be reproduced, stored in a retrieval
system, or transmitted by any means, electronic, mechanical, photocopying,
recording, or otherwise, without written permission from the publisher. No
patent liability is assumed with respect to the use of the information contained
herein. While every precaution has been taken in the preparation of this book
and the accompanying software, the publisher and author assume no
responsibility for errors or omissions. Neither is any liability assumed for
damages resulting from the use of the information contained herein.
Mix Software, Inc.
1132 Commerce Drive
Richardson, TX 75081
Sales: ............................. [phone]
Fax: ............................... [phone]
Technical Support: ........ [phone]
ISBN: 1-879810-11-5
ClDatabase Toolchest™ is a trademark of Mix Software, Inc.
dBASE® is a registered trademark of Borland International
ii ClDatabase Toolchest
Software License Agreement
Mix Software, Inc. grants the purchaser a single CPU license for use of the
accompanying software. By single CPU license, we mean that the software must
not be used on more than one computer at the same time. The purchaser shall not
make copies of the software except for the sole purpose of backing up the
software to protect against accidental loss of information on the original media.
Using Library Functions
The library functions included with this software may be linked with your own
functions, and the resulting executable program may be distributed without
obligation to Mix Software, Inc .. In other words, your own executable files may
be distributed royalty free. However, the library functions included with this
software may not be distributed as linkable object or library files, or as source
code files.
Using Sample Programs
The sample programs included with this software may not be distributed in any
form (executable, linkable, or source code). However, selected functions in the
sample programs may be extracted and incorporated into your own programs in a
manner similar to using our library functions. Your own executable programs
may be distributed royalty free if they perform a substantially different function
than the sample programs from which they are derived. Functions extracted from
sample programs may not be distributed as linkable object or library files, or as
source code files.
ClDatabase Too1chest 111
iv C/Database Too1chest
Table of Contents
Chapter 1 ---Introduction 1
Chapter 2 ---ISAM Databases 3
A Typical Problem ............................................................................... 3
A Computer Solution ........................................................................... 4
The ISAM Library ................................................................................ 6
Database Operations ...................................................................... 6
Indexes ........................................................................................... 7
Data Types ..................................................................................... 8
Variable Length Records ............................................................... 10
The CBT Library .................................................................................. 10
The ISAMCPP Library ......................................................................... 11
Chapter 3 ---ISAM Tutorial 13
Creating a New Database ..................................................................... 13
Opening an Existing Database ............................................................. 14
Making Indexes .................................................................................... 15
Adding Records .................................................................................... 17
Finding Records ................................................................................... 18
Deleting Records .................................................................................. 20
Chapter 4 ---ISAMCPP Tutorial 23
Creating a New Database ..................................................................... 23
Opening an Existing Database ............................................................. 24
Making Indexes .................................................................................... 25
Adding Records .................................................................................... 27
Finding Records ................................................................................... 28
Deleting Records .................................................................................. 30
Chapter 5 ---ISAM Library Functions 33
Chapter 6 ---ISAMCPP Library Functions 145
Chapter 7 ---CBT Library Functions 279
ClDatabase Toolchest v
Chapter 8 ---Tools 347
DBFTODB ........................................................................................... 347
DBTODBF ........................................................................................... 349
DUMPDATA ....................................................................................... 350
DUMPTREE ........................................................................................ 350
PRESSDB ............................................................................................. 351
Chapter 9 ---LDM Program 353
Creating a Database .............................................................................. 354
Making Indexes .................................................................................... 355
Adding Records .................................................................................... 357
Finding Records ................................................................................... 358
Editing and Deleting Records .............................................................. 359
Opening an Existing Database ............................................................. 359
Browsing Records ................................................................................ 362
Getting Help ......................................................................................... 364
Exiting LDM ........................................................................................ 364
Appendix A-ISAM Error Constants 365
Appendix B-CBT Error Constants 367
Appendix C-CBT Function Constants 369
Appendix D-CBT Context Constants 371
Appendix E-ISAM Function Summary 373
Appendix F -ISAMCPP Function Summary 375
Appendix G CBT Function Summary 377
Appendix H Installation 379
Index 383
vi ClDatabase Too1chest
Chapter 1
Introduction
The ClDatabase Toolchest'" is a collection of libraries and tools that enable you
to add sophisticated database management capabilities to your own applications.
Both C and C++ interfaces are provided so that you can create applications using
either of these two popular programming languages.
The libraries are designed to support large databases, limited only by the available
disk space. To make efficient use of disk space, the database records are
automatically stored in variable lengths. Typical databases contain string fields
that vary in length from one record to the next. Storing only the exact length of
each string eliminates the wasted disk space that occurs in database systems, such
as dBASE®, that support only fixed-length records.
Further efficiency is gained by allowing numeric values to be stored in either
string or binary format. In database systems like dBASE®, numeric values are
always translated to strings of digit characters before being stored in the database,
then translated back to binary after being retrieved from the database. When
database portability is paramount, this is the preferred method for storing numeric
values. However, when efficiency is paramount, the preferred method is to store
numeric values using their internal binary representation. This method requires no
translation and typically requires much less disk storage space.
The database indexes are implemented using an efficient derivation of the
balanced tree algorithm, sometimes referred to as a B+tree. This algorithm makes
it possible to find records quickly, even in very large databases. The index
management is handled by an independent library, thereby making the B+tree
algorithm available to programs that do not need the complete database
management facilities.
For use on networks or other multi-user environments, the libraries support file
and record locking. An entire database, or one or more records in a database can
be locked by a program, thereby blocking access by other programs. Databases
ClDatabase Toolchest
Chapter 1 -Intoduction
may be read-locked or write-locked. When a program read-locks a database, other
programs can read but not modify the database. A write-locked database cannot
be accessed at all by other programs, not even for reading.
This manual includes two short tutorial chapters (one for C and one for C++) that
cover some of the fundamental database library functions. Several example
programs illustrate how to create a new database, open an existing database, make
indexes, add records, find records, and delete records. Two additional chapters
describe all of the C and C++ library functions in alphabetical order. The use of
each library function is illustrated by a short example program. The source code
for all of the example programs is included on disk.
Several useful tools are provided that perform various database management
tasks. There are tools for converting to and from dBASE®f ormat files, for
compressing unused space from databases, and for displaying the contents of
database files. A program named LDM (Little Data Manager) allows you to create
new databases or edit existing databases. Since this program calls many of the
library functions, it provides a more complex example of how to use the database
libraries. The source code for these programs is also included on disk.
Many combinations of compilers and operating systems are currently supported.
For the supported compilers, all you have to do is select the appropriate compiler
when you install the software. Since the C and C++ source code is included, it is
possible to port the libraries to additional compilers and/or operating systems.
Because of the existing standards for the C and C++ languages, porting the
libraries to any standard compiler is generally quite easy. For many compilers, no
source code changes are necessary. All you have to do is create the appropriate
control files for building the libraries. You can start by installing the software for
one of the supported compilers, then modify the control files to conform to your
particular compiler.
Before proceeding further, you should first install the software. See the
Installation section of the appendix for instructions.
2 ClDatabase Toolchest