r a Twitter account, if the account 
exists, we must look up its <tt>id</tt> value. If the account
does not yet exist in the <tt>People</tt> table, we must insert 
the record and get the <tt>id</tt> value from the inserted
row.<br />
<br />
This is a very common pattern and is done twice in the program above.
This code shows how we look up the <tt>id</tt> for a 
friend's account when we have extracted a <code>screen_name</code>
from a <tt>user</tt> node in the retrieved Twitter JSON.<br />
<br />
Since over