Question

I have a relational database, however, there aren’t any foreign keys defined, and many of the tables are not InnoDB, so can’t support foreign keys anyway.

I would like to start experimenting with Doctrine on this database, but there is a lot of reference to foreign keys in the documentation, so I’m not sure if this is possible.

I’m anxious about diving in and changing table storage engines to InnoDB and defining tons of foreign keys, because I don’t want to impact performance if I don’t have to.

• Does Doctrine require foreign keys to be defined in order to manage associations between entities?
• If it isn’t required but optional, what features of Doctrine do I sacrifice if I don’t have foreign keys defined?

Answer 1

There is no reason for you to switch to InnoDB for Doctrine.

1. No.
2. I find the Doctrine’s CLI tools for updating and generating the database schema will often try to generate the SQL with foreign keys. You can manually set up the database, or modify the code it generates, to avoid this.

So, no, it is not a problem.