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.
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.