At 10:01 AM -0700 4/1/08, Robert DiFalco wrote:
I've been told that an index always contains the primary key.
By who? Ask for proof.
So if I have a LONG ID that is the primary key of table and create on index on LONG VALUE, the index on LONG VALUE will actually work as a typical compound index on ID,VALUE. My question is this, if I don't know that about MySQL and create my indices on purpose (i.e. not taking into account implementation details about MySQL) I would create the index explicitly on ID,VALUE. If I did that would I effectively have the same index as one on just VALUE or would there some how be duplicate data in the ID,VALUE index (i.e. ID, ID, VALUE)?
I'm not exactly sure what you're asking, but if I understand correctly, the answer is no. You might find these sections of the manual helpful: http://dev.mysql.com/doc/refman/5.0/en/indexes.html http://dev.mysql.com/doc/refman/5.0/en/multiple-column-indexes.html http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html -- Paul DuBois, MySQL Documentation Team Madison, Wisconsin, USA MySQL AB, www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
