Question

I am trying to use the same column to represent a has foreign key to different columns. This is because there could be an arbitrary number of tables to be indexed using this column.
Right now, my idea is to use a small varchar() field to represent which field they are indexing and then check for them my probably sub-querying for all that match the given field, then querying based on the id?
Is this a good method that would take advantage of MySQL indexing?
Are there any other better ways to accomplish this?

Answer 1

I usually use Abba’s solution for these sort of problems in a one-to-many relationship. Use a type field to define the table the foreign key reffers to.

If this comes up in a one-to-one relationship you may consider flipping the relationship around. Move the foreign key to the other tables. Any number of tables may link a foreign key to the single original table.