A select statement by itself never acquires a lock on the corresponding table(s). In actual practice I have found that no amount of locking has a bearing on a select statement issued from another session. The rule we were all taught in Oracle 4+ about "readers do not block writers and writers do not block readers" is still true. Now as to "writers blocking writers" that remains a different story. For the most part I totally discourage the use of the "lock table" command among my users and developers. It can cause lock escalation that can get totally out of control and sometimes even cause Oracle to do dead-lock detection with unexpected application failure. I've enough trouble getting our developers to do any kind of robust error detection and handling, never mind them causing an error intentionally. Now if you want to use the "select .. for update of" that's fine. Otherwise I highly recommend allowing the RDBMS to acquire locks for you as it sees fit. It will acquire the lowest level lock that is consistent with what your trying to do. Dick Goulet Oracle Certified 8I DBA & 16+ year Oracle practioner. ____________________Reply Separator____________________ Author: GL2Z/ INF DBA BENLATRECHE <[EMAIL PROTECTED]> Date: 7/24/2001 12:35 AM If I am not wrong you can use a SELECT ........ FOR UPDATE -----Message d'origine----- De : Hamid Alavi [mailto:[EMAIL PROTECTED]] Envoyé : mardi 24 juillet 2001 03:45 A : Multiple recipients of list ORACLE-L Objet : Lock hi all, Aay body know, how you can control the lock during the sql code. eg select a,b,c from tablea with NO LOCK. how you can control the locking. thanks in advance all of you The information contained in this message and any attachments is intended only for the use of the individual or entity to which it is addressed, and may contain information that is PRIVILEGED, CONFIDENTIAL and exempt from disclosure under applicable law. If you have received this message in error, you are prohibited from copying, distributing, or using the information. Please contact the sender immediately by return e-mail and delete the original message from your system. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Hamid Alavi 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: GL2Z/ INF DBA BENLATRECHE 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: 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).
