anonymous wrote : | I don't know what the objective of this is so I really don't know how | | INSERT_MESSAGE_CONDITIONAL=INSERT INTO JBM_MSG (MESSAGE_ID, RELIABLE, EXPIRATION, TIMESTAMP, PRIORITY, TYPE) SELECT ?, ?, ?, ?, ?, ? FROM JBM_DUAL WHERE NOT EXISTS (SELECT MESSAGE_ID FROM JBM_MSG WHERE MESSAGE_ID = ?) | | a non persistence message, would be eventually persisted if the memory is full, on that case a pageReference will insert the message *if* the message is not inserted yet. To avoid a select before the insert, we do the INSERT with SELECT, and we use a dual table (on that case, called JBM_DUAL) as an intermediator on the insert. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4080165#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...