Hmmmm? Sequences are not created "on" the dual table. Sequences exist as independent entities. Ofttimes, sequence values are selected using the dual table (e.g., select seqname.nextval from dual) -- this is a coding choice. Performance of queries that select from the dual table are generally not "inviting poor performance" (although I've seen some postings on how to improve their performance).
If I were you, I would do some more reading up on sequences in the Concepts manual and not worry too much about the performance. Suggest to the developers that they use the sequences directly whenever possible rather than selecting from dual as in the following: One method: select seqname.nextval into local_var from dual; insert into destination_table (...id_column...) values (...local_var...); Better method: insert into destination_table (...id_column...) values (...seqname.nextval...); And, if the value is needed for other things: insert into destination_table (...id_column...) values (...seqname.nextval...) returning id_column into local_var; HTH Kevin Kennedy First Point Energy Corporation If you take RAC out of Oracle you get OLE! What can this mean? -----Original Message----- Sent: Tuesday, July 30, 2002 10:54 AM To: Multiple recipients of list ORACLE-L I have a request from one of our developers to create two new sequences on the DUAL table. This seems like a bad idea to me. I've never had such a request in the past. I asked for clarification on why this is needed and I didn't get a lot of details yet. Is this something that is standard operating procedure? My understanding that interfacing with the DUAL table is usually inviting poor performance. Plus, I don't like to mess around with system tables, in general. Under what circumstances would it be justified to create sequences on the DUAL table? Should I just flat-out refuse this request and if so, why? Thanks, Cherie Machler Oracle DBA Gelco Information Network -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: kkennedy INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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).
