Question

What is the best method of implementing multi-valued attributes in a relational database?

I’m trying to convert an ER diagram into a relational schema, and I have this problem:

I have a table of ‘Programmes’ with attributes such as Programme ID, type, title, description etc – but then also have Actors – obviously this is multi-valued as a specific programme will have multiple actors in.

How should I represent this?

Answer 1

If an actor can have Many programmes and a programme can have Many actors this sounds like a classic Many-to-Many relationship. Create a third table called programme_actors or perhaps cast with two columns: the primary keys of each of the two joined tables.