Hi! > Trailing columns with NULL values do not occupy any space, not even a length > byte.
Yep, I missed this one. Also, when few trailing null columns aren't stored in a row, this particular rows column count is smaller as well, so the column count in physical table storage can vary... > Non-trailing columns with NULL values have a constant value of 0xFF (255) in > the length byte consuming just the one byte. Yep, and this means that even fixed-length CHAR datatypes don't consume any space except length byte if they contain nulls. I once saw a recommendation to store your data in char columns if you don't want to have to worry about row size changes and PCTFREE setting... which is mostly a stupid suggestion anyway and doesn't work in case of nulls either. Tanel. P.S. Tim, I assume that we'll meet at RMOUG training days this Feb? -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tanel Poder INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).