Re: Do null columns take up space?

Mike Segel wrote: > > Mark D Stock wrote: > > > Don't forget VARCHAR, TEXT and BYTE. These are all variable length but only available > > in OnLine. > > > Didn't forget it. Actually when a table has a variable lenght element, > I believe that the element is stored separately. This is true of BLOBs, > then the table need to only have a pointer structure which points to the > table space, offset, and size of the blob, or something like that. True for blobs, if they are stored in the tablespace they get their own pages. However, VARCHARs are stored in normal data pages and that's where the fun starts! If a VARCHAR becomes too large for it's original location then it moves to remainder pages and a pointer is left in the original location. That's a very simplistic description so don't shoot me JL! -- Mark. +-------------------------------------------------------------------------+ |Mark D. Stock - The West Solutions Group http://www.west.co.za | | | |Email: marks@west.co.za +------------------------------------------------+ |Tel: +27 11 803 2151 |If it doesn't work... force it! | |Fax: +27 11 803 2189 |If it breaks... it needed replacing anyway! | |Cell: +27 83 250 2325 |Well, that's how I code anyway! | +------------------------+------------------------------------------------+