PDO_ODBC is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to databases through ODBC drivers or through the IBM DB2 Call Level Interface (DB2 CLI) library. PDO_ODBC currently supports three different "flavours" of database drivers:
Supports access to IBM DB2 Universal Database, Cloudscape, and Apache Derby servers through the free DB2 express-C client.
Supports access to database servers through the unixODBC driver manager and the database's own ODBC drivers.
Offers a compile option for ODBC driver managers that are not explicitly supported by PDO_ODBC.
On Windows, php_pdo_odbc.dll has to be enabled as extension in php.ini. It is linked against the Windows ODBC Driver Manager so that PHP can connect to any database cataloged as a System DSN.
PDO_ODBC is included in the PHP source. You can compile the PDO_ODBC extension as either a static or shared module using the following configure commands.
./configure --with-pdo-odbc=ibm-db2,/opt/IBM/db2/V8.1/
If you do not supply a location for the DB2 libraries and headers to the configure command, PDO_ODBC defaults to /home/db2inst1/sqllib.
./configure --with-pdo-odbc=unixODBC,/usr/local
./configure --with-pdo-odbc=generic,/usr/local,libname,ldflags,cflags
The constants below are defined by
this driver, and will only be available when the extension has been either
compiled into PHP or dynamically loaded at runtime. In addition, these
driver-specific constants should only be used if you are using this driver.
Using driver-specific attributes with another driver may result in
unexpected behaviour. PDO::getAttribute() may be used to
obtain the PDO::ATTR_DRIVER_NAME attribute to check the
driver, if your code can run against multiple drivers.
PDO_ODBC_TYPE
(string)
PDO::ODBC_ATTR_USE_CURSOR_LIBRARY
(int)
This option controls whether the ODBC cursor library is used. The ODBC cursor library supports some advanced ODBC features (e.g. block scrollable cursors), which may not be implemented by the driver. The following values are supported:
PDO::ODBC_SQL_USE_IF_NEEDED (the default):
use the ODBC cursor library when needed.
PDO::ODBC_SQL_USE_DRIVER:
never use the ODBC cursor library.
PDO::ODBC_SQL_USE_ODBC:
always use the ODBC cursor library.
PDO::ODBC_ATTR_ASSUME_UTF8
(bool)
Windows only. If true, UTF-16 encoded character data (CHAR,
VARCHAR and LONGVARCHAR) is converted to
UTF-8 when reading from or writing data to the database.
If false (the default), character encoding conversion may be done by the driver.
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| pdo_odbc.connection_pooling | "strict" | INI_ALL |
|
| pdo_odbc.db2_instance_name | NULL | INI_SYSTEM |
This deprecated feature will certainly be removed in the future. |
Here's a short explanation of the configuration directives.
pdo_odbc.connection_pooling
string
Whether to pool ODBC connections. Can be one of "strict",
"relaxed" or "off" (equals to
""). The parameter describes how strict the connection
manager should be when matching connection parameters to existing pooled
connections. strict is the recommend default, and
will result in the use of cached connections only when all the connection
parameters match exactly. relaxed will result in
the use of cached connections when similar connection parameters are
used. This can result in increased use of the cache, at the risk of
bleeding connection information between (for example) virtual hosts.
This setting can only be changed from the php.ini file, and affects the entire process; any other modules loaded into the process that use the same ODBC libraries will be affected too, including the Unified ODBC extension.
relaxed matching should not be used on a shared
server, for security reasons.
Leave this setting at the default strict setting
unless you have good reason to change it.
pdo_odbc.db2_instance_name
string
If you compile PDO_ODBC using the db2 flavour,
this setting sets the value of the DB2INSTANCE environment variable on
Linux and UNIX operating systems to the specified name of the DB2
instance. This enables PDO_ODBC to resolve the location of the DB2
libraries and make cataloged connections to DB2 databases.
This setting can only be changed from the php.ini file, and affects the entire process; any other modules loaded into the process that use the same ODBC libraries will be affected too, including the Unified ODBC extension.
This setting has no effect on Windows.