Identifier Generation Strategies

The previous example showed how to use the default identifier generation strategy without knowing the underlying database with the AUTO-detection strategy. It is also possible to specify the identifier generation strategy more explicitly, which allows you to make use of some additional features.

Here is the list of possible generation strategies:

• AUTO (default): Tells Doctrine to pick the strategy that is preferred by the used database platform. The preferred strategies are IDENTITY for MySQL, SQLite, MsSQL and SQL Anywhere and SEQUENCE for Oracle and PostgreSQL. This strategy provides full portability.
• SEQUENCE: Tells Doctrine to use a database sequence for ID generation. This strategy does currently not provide full portability. Sequences are supported by Oracle, PostgreSql and SQL Anywhere.
• IDENTITY: Tells Doctrine to use special identity columns in the database that generate a value on insertion of a row. This strategy does currently not provide full portability and is supported by the following platforms: MySQL/SQLite/SQL Anywhere (AUTO_INCREMENT), MSSQL (IDENTITY) and PostgreSQL (SERIAL).
• UUID: Tells Doctrine to use the built-in Universally Unique Identifier generator. This strategy provides full portability.
• TABLE: Tells Doctrine to use a separate table for ID generation. This strategy provides full portability. *This strategy is not yet implemented!*
• NONE: Tells Doctrine that the identifiers are assigned (and thus generated) by your code. The assignment must take place before a new entity is passed to EntityManager#persist. NONE is the same as leaving off the @GeneratedValue entirely.