Platforms abstract query generation and the subtle differences of the supported database vendors. In most cases you don’t need to interact with the Doctrine\DBAL\Platforms package a lot, but there might be certain cases when you are programming database independent where you want to access the platform to generate queries for you.
The platform can be accessed from any Doctrine\DBAL\Connection instance by calling the getDatabasePlatform() method.
<?php $platform = $conn->getDatabasePlatform();
Each database driver has a platform associated with it by default. Several drivers also share the same platform, for example PDO_OCI and OCI8 share the OraclePlatform.
Doctrine provides abstraction for different versions of platforms if necessary to represent their specific features and dialects. For example has Microsoft added support for sequences in their 2012 version. Therefore Doctrine offers a separate platform class for this extending the previous 2008 version. The 2008 version adds support for additional data types which in turn don’t exist in the previous 2005 version and so on. A list of available platform classes that can be used for each vendor can be found as follows:
- MySqlPlatform for version 5.0 and above.
- MySQL57Platform for version 5.7 and above.
- OraclePlatform for all versions.
7.3. Microsoft SQL Server¶
- SQLServerPlatform for version 2000 and above.
- SQLServer2005Platform for version 2005 and above.
- SQLServer2008Platform for version 2008 and above.
- SQLServer2012Platform for version 2012 and above.
- PostgreSqlPlatform for all versions.
- PostgreSQL91Platform for version 9.1 and above.
- PostgreSQL92Platform for version 9.2 and above.
7.5. SAP Sybase SQL Anywhere¶
- SQLAnywherePlatform for version 10 and above.
- SQLAnywhere11Platform for version 11 and above.
- SQLAnywhere12Platform for version 12 and above.
- SQLAnywhere16Platform for version 16 and above.
- SqlitePlatform for all versions.
- DrizzlePlatform for all versions.
It is highly encouraged to use the platform class that matches your database vendor and version best. Otherwise it is not guaranteed that the compatibility in terms of SQL dialect and feature support between Doctrine DBAL and the database server will always be given.
If you want to overwrite parts of your platform you can do so when creating a connection. There is a platform option you can pass an instance of the platform you want the connection to use:
<?php $myPlatform = new MyPlatform(); $options = array( 'driver' => 'pdo_sqlite', 'path' => 'database.sqlite', 'platform' => $myPlatform ); $conn = DriverManager::getConnection($options);
This way you can optimize your schema or generated SQL code with features that might not be portable for instance, however are required for your special needs. This can include using triggers or views to simulate features or adding behaviour to existing SQL functions.
Platforms are also responsible to know which database type translates to which PHP Type. This is a very tricky issue across all the different database vendors, for example MySQL BIGINT and Oracle NUMBER should be handled as integer. Doctrine 2 offers a powerful way to abstract the database to php and back conversion, which is described in the next section.