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_ RU.LINUX (2:5077/15.22) ___________________________________________ RU.LINUX _
From : Boris Tobotras 2:5020/510 04 Oct 98 17:53:52
Subj : Using the Xbase DBMS in a Linux Environment
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"Linux Gazette...making Linux just a little more fun!"
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Using the Xbase DBMS in a Linux Environment
By Gary Kunkel
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Introduction
The Xbase file structure has been around quite a while and was one of the
first widely available DBMS tools for micro computers. It has become a
de-facto industry standard for text based databases and is supported by many
vendors to include the Borland Database Engine, Microsoft's FoxPro, Clipper,
Sequitor's Codebase and others. Xbase type datafiles will be with us for a
while.
The Startech Web Server at http://www.startech.keller.tx.us/xbase/xbase.html
maintains a public domain, open source C++ library for accessing Xbase type
datafiles in a multi-user environment. The library supports automatic record
locking, memo fields (both dBase III and IV versions), and .NDX style
indices. There is also an API for interfacing the library to an Apache Web
Server and providing database access to web pages. Several example programs
provide a framework for creating, browsing and updating databases. There are
examples which demonstrate how to use the library with an Apache Web Server
and using the library in conjunction with the wxWindows library. Some
readers of this article will recognize the wxWindows library as a cross
platform GUI C++ library.
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System Requirements
In order to use the Xbase DBMS library, you'll need to have a C/C++
compiler. The original library was built on a Slackware distribution with
the GNU public domain compiler, but there are examples on the site for using
the library on other platforms including Windows, SUN, and VMS.
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Getting Sources
To downloading the library sources, point your web browser to
http://www.startech.keller.tx.us/xbase/xbase.html and select the latest
version, which at the time of this writing is version 1.7.4 dated 6/18/98.
There are a couple of flavors available, but for the purpose of this
article, download the UNIX tar version. Also, you may want to grab the HTML
documentation for using the library at the same time. Alternatively, you can
get the software via ftp ftp.startech.keller.tx.us and retrieve the software
from the pub/xbase directory.
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Installing Sources
To install the Xbase library under the /usr/local directory, execute the
following commands: cd /usr/local and mkdir xbase. The next step is to set
up access rights to the Xbase directory tree. Your site may have specific
protocols on directory access rights which you may need to address at this
point. If not, then the commands "chown YOURUSERID.users xbase", then "chmod
775 xbase" will get you going.
Now create a source directory and copy the source code into it: "cd xbase",
"mkdir src", "cp /home/of/xbase.tar.gz /usr/local/xbase/src", "cd
/usr/local/xbase/src", "gunzip xbase.tar.gz" and lastly "tar -xvf
xbase.tar". At this point the Xbase source code should be in the
/usr/local/xbase/src directory and be ready to build the library.
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Building the Library
Before building the library, review the options.h file. This file contains
any of the Xbase configuration switches you may want or need to change
depending on what you are trying to do. To build a DLL library, type "make
dll". To build a static library, type "make all".
It should compile cleanly. Errors at this point can often be traced to the
.h header files currently in use at your site. If you run into errors at
this point, notify [email protected] for help building the
library.
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Building a Sample Program
This sample program demonstrates a simple program which creates a sample
database and index.
/* sample1.cpp */
#include "xbase.h"
main()
{
Schema MyRecord[] =
{
{ "FIRSTNAME", CHAR_FLD, 15, 0 },
{ "LASTNAME", CHAR_FLD, 20, 0 },
{ "BIRTHDATE", DATE_FLD, 8, 0 },
{ "AMOUNT", NUMERIC_FLD, 9, 2 },
{ "SWITCH", LOGICAL_FLD, 1, 0 },
{ "FLOAT1", FLOAT_FLD, 9, 2 },
{ 0,0,0,0 }
};
/* define the classes */
XBASE x; /* initialize xbase */
DBF MyFile( &x ); /* class for table */
NDX MyIndex( &MyFile ); /* class for index 1 */
SHORT rc; /* return code */
if(( rc = MyFile.CreateDatabase( "MYFILE.DBF", MyRecord, OVERLAY )) !=
NO_ERROR )
cout << "\nError creating database = " << rc << "\n";
else
{
/* define a simple index */
if(( rc = MyIndex1.CreateIndex(
"MYINDEX.NDX", "LASTNAME", 0, 1 )) != NO_ERROR )
cout << "\nError creating index 1 = " << rc << "\n";
}
MyFile.CloseDatabase(); /* Close database and associated indexes */
return 0;
}
Assuming you keyed the program source into directory
/usr/local/xbase/myproj, type "g++ -c -I/usr/include
-I/usr/src/linux/include/asm-i386 -I../src sample1.cpp" to compile the
program and type "g++ -o sample1 sample1.o ../src/xbase.a" to link edit the
program. The asm-i386 directory in the above include line is for Linux
running on the Intel platform. Other platforsm require the correct include
directory.
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Conclusion
In conclusion, I'd like to say that although the Xbase library is not a 100%
complete Xbase solution, it is a stable and reliable library capable of
handling various database requirements. If you are looking for database
libraries in general, or need access to Xbase files in particular, give
Xbase DBMS a try. If you are a C programmer and new to C++ object oriented
programming, the Xbase DBMS is easy to learn and will help transition you to
the world of object oriented programming. If you have never programmed in C
or C++ before, this library should provide complete enough examples to get
you started programming in C/C++ with confidence.
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Copyright (C) 1998, Gary Kunkel
Published in Issue 33 of Linux Gazette, October 1998
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--
Best regards, -- Boris.
Never make anything simple and efficient when a way can be found to
make it complex and wonderful.
--- Gnus v5.5/XEmacs 20.3 - "London" * Origin: Linux inside (2:5020/510@fidonet)
