How can I compare two databases?

I have two databases - I will call them database A and database B.

I want to run some code on database A, and then check if database A became identical to database B.

How can I compare two databases? I want to compare them in terms of structure, not content.

Any suggestions? Thank you!there r couple of tools avialable in the market.
Check Red Gate Tools|||Does anybody know such a product that is free...I find a couple of products but they have only 14 days free trial period. I need such a tool for longer time...|||Does anybody know such a product that is free...I find a couple of products but they have only 14 days free trial period. I need such a tool for longer time...

Longer time? much better to make a program for that in that case. VB or something.|||If the databases are on the same server, then compare the sysobjects, syscolumns, and other system tables between the two using a full outer join on the natural keys, and listing any exceptions or discrepancies.|||Here's the poor mans way...

Generate a db script in EM for both databases. Then compare both text files.