Hi, In a docuement such as Invoice Form, we have a header and a couple of records for the detail. In header table, Invoice# can be the PRIMARY KEY but in detail table, Invoice# is not unique. I think there are two solutions to choose a Primary Key (in MyISAM type) :
1) Adding an id field ( auto_increment ) and choose it as PRIMARY KEY in this case we have to add another index on Invoice# for making relation with the header table 2) There is another field in detail table with "timestamp" type for keeping the last change on the record. I want to select ( Invoice# + myTimestamp ) for PRIMARY KEY. in this case I don't need to add a new fields ( id ) and another index ( on Invoice# ) to the table. which one do you prefer and usually use? thank -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
