 we are
using integer keys to link tables. The basic patterns are:
</font><ol type="1"><li><font color="black">Creating tables with primary keys and constraints.</font><br />
<br />
</li><li><font color="black">When we have a logical key for a person (i.e. account
name) and we need the <tt>id</tt> value for the person.
Depending on whether or not the person is already
in the <tt>People</tt> table, we either need to: 
(1) look up the person in the <tt>People</tt> table and 
retrieve the <tt>id</tt> value for