KaliMa KaliMa - 1 year ago 80
Java Question

Weak foreign keys in SQLite, possible?

I have a table with a foreign key to another table's id field.

For example Book.author_id foreign key of (to?) Author.id

However sometimes I want to have the author_id be null if I want to say the author is unknown. However this fails the table constraint for foreign keys.

Is there a way around this?

Answer Source

To get a foreign key constraint that allows NULL values, do nothing; it's the default.

If you wanted to force it to always have a valid reference, you would have to add a NOT NULL constraint.

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