Re: Rowids in Informix Databases

Art S. Kagel wrote: > On Tue, 12 Oct 2004 07:32:44 -0400, Vijay Kumar wrote: > > ROWID is not a REAL column in the table (unless the table is fragmented that > is). It is the relative address of the row which is simply treated as if it > were a column. If your table is fragmented, the ROWID pseudo-column will not > work because since the rowids are relative to the dbspace the fragment lives > in it is not unique across fragments, only for a single fragment table. If > your table is fragmented you can have the engine add a hidden SERIAL type > column called "rowid" which will be automatically populated for you and which > you can use as if it were a true rowid. You do this by adding the WITH ROWIDS > clause to the CREATE TABLE statement before the FRAGMENT BY clause or by > altering the table with: ALTER TABLE mytablename ADD ROWIDS; a quick question. If a fragmented table is created WITH ROWIDS, what happens when an update to a variable length column like varchar forces the engine to move the row to some other page. Does the rowid change (reflecting the new address of the row) or the old one is retained.