The differences between GeneratedValue strategies

Question

In the Doctrine docs they mention that there exists a few different strategies for the @GeneratedValue annotation:

• AUTO
• SEQUENCE
• TABLE
• IDENTITY
• UUID
• CUSTOM
• NONE

Would someone please explain the differences between all thees strategies?

Answer 1

Check the latest doctrine documentation

Here is a summary : 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 and MsSQL 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 and 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
• PostgreSQL => SERIAL

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.

SINCE VERSION 2.3 :

UUID: Tells Doctrine to use the built-in Universally Unique Identifier generator. This strategy provides full portability.