total participation

[Anon]

hi
I am a cs student at university of Illinois at Urbana Champaign.I need help on the following matter.How do we ensure total participation of two entites into a relationship.
I have two entities books(bid, bname)and author(aname) and relationship set written_by. All authors have written books and all books have authors i.e. there is many to many relationship.

Any help is appreciated.

Thanks
Harsh

[Anon]

What exactly do you mean by a "total participation"?

[Anon]

Are you wanting to ensure that every book has at least one author assigned to it? Or are you wondering how to join the two tables in such a way as you get one book, with each author concatenated off to the side?

[Anon]

hi
I want that every book that appears in the books table should participate in the written_by table i.e. every book should have atleast one author.