Extract Relationships from Tables in SQL Server.....

Hi,
I am connecting with SQL server with ADODB(odbc) and I am working with vb6.
I must extract from sql server the relationships wich there are between tables and i must extract which are the Primary Key and the Foreign Key from the tables.
How can I do it? Can you help me with a little example?
I want make it only by code of Visual basic 6

thanks

Query on the sysobjects table in the SQL Server and just look from there.