Hi, well the problem is that these unique numbers(aktenzeichen) are not generated by me. They are in the DB (not my problem how they go in there). So when the systems receives an email, this email needs one of these numbers(aktenzeichen). So i need to get the umber and delete that number and make sure that no other process that might me running at the same time, gets the same number!
any ideas?? > [EMAIL PROTECTED] wrote: > > > Hi. > > I am having problems with LOCK and JAVA. > > > > I need to make sure that no other Process is reading from a > > table, because in that table are unique numbers. > > So i want to lock the table, select a number(select * and > > read the first numer), delete this number and release. > > No answer directly to your question, but another idea. > What do you want to do, have a unique (the next) number for the next insert? > Why don't you use sequences resp. DEFAULT SERIAL resp. the datatype SERIAL > as described here > http://www.sapdb.org/7.4/how_tos/numbergen/howto_producenumgen_eng.htm > and discussed in this list several times. > > Maybe this could solve the problem you want to handle with your lock/select/unlock- > sequence ... > > Elke > SAP Labs Berlin > > > > > But somehow the lock is not working. > > Here is what I have tried: > > > > Connection con = getCon(); > > Statement stmt = con.createStatement(); > > stmt.execute("LOCK (NOWAIT) TABLE benutzer IN SHARE > > MODE TABLE benutzer IN EXCLUSIVE MODE "); > > System.out.println("before insert"); > > stmt.execute("INSERT into test (name) values ('hallo')"); > > System.out.println("after insert"); > > > > Thread.sleep(10000); > > > > stmt.execute("UNLOCK TABLE benutzer IN SHARE MODE TABLE > > benutzer IN EXCLUSIVE MODE "); > > //resultSet.close(); > > stmt.close(); > > con.close(); > > System.out.println("done"); > > > > > > I am starting this twice and both tell me instantly before > > insert, after insert. > > AS I understand lock, the first task should tell me that, but > > the second should only tell before! > > > > What am I doing wrong? > > > > How can I prevent that a unique number is read twice by > > different task? > > > > Please help! > > > > Phil > > > > > > -- > > MaxDB Discussion Mailing List > > For list archives: http://lists.mysql.com/maxdb > > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > -- MaxDB Discussion Mailing List For list archives: http://lists.mysql.com/maxdb To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
