Doctrine_Connection is a wrapper for database connection. It handles several things: <ul> <li \> Handles database portability things missing from PDO (eg. LIMIT / OFFSET emulation) <li \> Keeps track of Doctrine_Table objects <li \> Keeps track of records <li \> Keeps track of records that need to be updated / inserted / deleted <li \> Handles transactions and transaction nesting <li \> Handles the actual querying of the database in the case of INSERT / UPDATE / DELETE operations <li \> Can query the database using the DQL API (see Doctrine_Query) <li \> Optionally validates transactions using Doctrine_Validator and gives full information of possible errors. </ul>