Re: TRUTH about ROWID

[Charles Francis (ancrcs4!cfrancis@ancrcs4.attmail.com) wrote] > According to the Informix-On-line Dynamic Server Administrators Guide > Version 7.1 Volume 2 page 43-35 rowid is still supported. As with earlier > On-line releases rowid is a combination of a page identification number and > the slot table entry number on the page for nonfragmented tables. Fragmented > table may have rowid, but; it is implemented differently. > The Informix-On-line Dynamic Server Administrators Guide Version 7.1 > Volume 1 page 16-20 explains the creation of rowid for fragmented tables. > Rowid is may be created by use of any of the follow clauses: > WITH ROWID in CREATE TABLE > ADD ROWID in ALTER TABLE > INIT in ALTER FRAGMENT > Any of these implementations of ROWID on fragmented tables adds a 4 byte > unique value the a table. > For more information I suggest finding access to the 7.1 manuals. I have not tested it, but I understand that when you do this, you are actually creating a new column in the table. The rowid is *already* there! The problem is that it is not unique within the fragmented table. It *is* unique within the fragment, though. When you add the rowid as mentioned above you are asking the engine to add a column which is stored as a serial value. And, as we all know, you can have only one serial column per table. Yes, this *does* count as the serial column. Long story short: If you add the unique rowid, you cannot have an additional serial column. Can anyone verify this? +------------------------------------------------------------------------+ | Bob Payne Internet: bobp@dev.dsc.dalsys.com | | Systems Engineer : bpayne@netcom.com | | Dallas Systems Corporation Voice: (214) 383-2238 | +------------------------------------------------------------------------+