Adding PDO as hard dependency as per discussion in #808

Close #713
DBAL-1030

Added missing filtering of table name assets in DB2SchemaManager

Close #2704

#2704 - Removed hacky handling of error handler restore operations - restoring twice in the test instead

MySQL: Fix primary key alteration when adding new columns

Fix docs for Doctrine\DBAL\Id\TableGenerator

primary key on MySQL platform.

MySqlPlatform: Fix default isolation level

Default isolation level on mysql is REPEATABLE READ

https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_tx_isolation

[Oracle] getListTableColumnsSQL returns columns ordered by position instead of by name.

Add missing SSL parameters to pdo_pgsql driver

Fix copy+paste error in testListTableColumns

Slash before '_' in postgresql like condition with 'pg_' prefix

Add undocumented oci8 persistent connections

The oci8 driver can connect using oci_pconnect to make persistent connections. Doctrine has support for this if the persistent boolean value is set to true in the documentation. However, this information was not documented.

Revert conditional PGSQL & MARIADB change