Converting MySQL ADOdb PHP applications to DB2 UDB

Active Data Object Database (ADOdb) for PHP is a database abstraction library 

modeled on Microsoft s ADO for building dynamic Web pages with database 

support. A PHP Web application can use this database class library to access 

any supported database

.

 ADOdb supports MySQL, PostgreSQL, Oracle, 

Microsoft SQL Server, Sybase, Informix, Access, FoxPro, Interbase, ODBC, and 

ADO for true cross platform database independence, which means a PHP 

application written for one database can be easily converted to another 

database.

As both MySQL and DB2 UDB are supported by ADOdb for the PHP library, the 

application conversion will be much easier than other incompatible APIs. ADOdb 

architecture is built in such a way that all the database dependant code are 

stored in stub functions, which means you can easily support your database 

specific functionality by changing the stub file. 

So, for using DB2 UDB from your PHP application you need 

adodb db2.inc.php

instead of 

adodb mysql.inc.php

. As ADOdb function calls will remain the same 

for both the databases, the only change you may need is changing some 

database specific formats.

The ADOdb library provides a wrapper around MySQL API for supporting the 

MySQL database and wrapper around DB2 ODBC Driver for DB2 UDB. So, you 

need DB2 ODBC Driver for using ADOdb libraries. 

The MySQL ADOdb PHP application can be ported to DB2 UDB by doing the 

following changes at various levels of the application:

Loading ADOdb driver

Before using the ADOdb library you need to include PHP ADOdb libraries and 

initialize ADOdb variables in your program. ADOdb requires loading of at least 

two files: 

adodb.inc.php

, which contains all the functions used by all database 

classes

adodb .inc.php,

 which contains database specific code

For instance, MySQL code requires the loading of 

adodb mysql.inc.php

, and 

now you need to change it to a 

adodb db2.inc.php

 file. This can be done by 

changing 

ADOLoadCode( mysql )

 to 

ADOLoadCode( db2 )

; this code actually 

makes sure that you load only the required driver. Example 7 30 shows the 

code for initialization and the changes required for DB2 UDB.

Example 7 30   Loading ADOdb driver for MySQL and DB2 UDB

include( /home/itso/adodb/adodb.inc.php ); 

$ADODB_CACHE_DIR =  /home/itso/adodb/cache ; 

 Chapter 7. Application porting 

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