When two models are related to each other, Doctrine automatically generates foreign key constraints in the MySQL database beautifully. The default behaviour for onDelete and onUpdate RESTRICT, but can also be set to SET NULL or CASCADE.
Now, I want to create a migration diff from an existing database compared to a YAML file. To do this, I use the Doctrine::generateModelsFromDB() function. I use an overloaded versoin of Doctrine_Migration_Diff to do the diff work for me, that takes care of non-matching class names, MySQL field lengths etc. It does all stuff nicely, but there is a problem with these foreign key constraints.
When I create PHP classes from a MySQL database, it seems Doctrine doesn’t set the ‘onDelete’ and ‘onUpdate’ to the appropriate values. When I then try to diff these PHP classes against classes that do have ‘onDelete’ and/or ‘onUpdate’ set, Doctrine tries to add a new foreign key that already exists, and MySQL fails.
I worked around this error temporarily by manually ignoring all changed foreign keys in my overloaded Doctrine_Migration_Diff, but this really is no solution.
What I want: if Doctrine thinks a new Foreign Key needs to be added, chance is it already exists, and what its onDelete and onUpdate behaviour are set to. How can I check that, if I have the local field name and the foreign field name?
P.S. If somebody is certain this was fixed in Doctrine 1.2 (which I doubt), please don’t advise me to upgrade. I have specific reasons to work with 1.1 in this case, but that is a different story. I would rather be pointed into the direction of what code change provided this fix, that might be a step closer to a workaround.
To answer my own question: I looked into the Doctrine source code for quite some time, and found out that the MySQL importer does not have functionality to do this.
In other words, it is impossible without extending Doctrine yourself.