On Fri, Nov 16, 2007 at 03:50:20PM -0300, Jo??o Paulo Zavanela wrote: > How many fields is recomended to create a primary key? > I'm thinking to create one with 6 fields, is much? Normally a primary key would just be a single column. When you start going to that many I'd probably have a serial column as the primary key, and a UNIQUE index on those six fields. Depends on what you're doing, though unless you've got a few years experience I'd be tempted to stay away from primary keys of more than a single column. Sam ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match