In addition to normal ODBC support, the Unified ODBC functions in PHP allow you to access several databases that have borrowed the semantics of the ODBC API to implement their own API. Instead of maintaining multiple database drivers that were all nearly identical, these drivers have been unified into a single set of ODBC functions.
Note: There is no ODBC involved when connecting to the above databases. The functions that you use to speak natively to them just happen to share the same names and syntax as the ODBC functions. The exception to this is iODBC. Building PHP with iODBC support enables you to use any ODBC-compliant drivers with your PHP applications. iODBC is maintained by OpenLink Software. More information on iODBC, as well as a HOWTO, is available at www.iodbc.org.
The following databases are supported by the Unified ODBC functions: Adabas D, IBM DB2, iODBC, Solid, and Sybase SQL Anywhere. To access these databases you need to have the required libraries installed.
Please see the Installation on Unix Systems chapter for more information about configuring PHP with these databases.
The behaviour of the ODBC functions is affected by settings in the global configuration file php.ini.
Table 1. Unified ODBC Configuration Options
Note: Entries marked with * are not implemented yet.
Here is a short explanation of the configuration directives.
Whether to allow persistent ODBC connections.
Check that a connection is still valid before reuse.
The maximum number of persistent ODBC connections per process.
The maximum number of ODBC connections per process, including persistent connections.
Handling of LONG fields. Specifies the number of bytes returned to variables.
Handling of binary data.
This extension does not define any resource types.
This extension does not define any constants.