(no version information, might be only in CVS)
PDO::lastInsertId -- 
     Returns the ID of the last inserted row or sequence value
    
Description
string 
PDO::lastInsertId ( [string name] )
     Returns the ID of the last inserted row, or the last value from a
     sequence object, depending on the underlying driver. For example,
     PDO_PGSQL() requires you to specify the name of
     a sequence object for the name parameter.
    
Note: 
      This method may not return a meaningful or consistent result across
      different PDO drivers, because the underlying database may not even
      support the notion of auto-increment fields or sequences.
     
Return Values
     If a sequence name was not specified for the name
     parameter, PDOStatement::lastInsertId() returns a
     string representing the row ID of the last row that was inserted into
     the database.
    
     If a sequence name was specified for the name
     parameter, PDOStatement::lastInsertId() returns a
     string representing the last value retrieved from the specified sequence
     object.
    
     If the PDO driver does not support this capability,
     PDO::lastInsertID() triggers an
     IM001 SQLSTATE.