No, transactions are not rolled back as soon as an error occurs. But you may be using a client-application which applies this policy. For example, if you are using the mysql command-line client, then it normally stops executing when an error occurs and will quit. Quitting while a transaction is in progress does cause it … Read more
If you define table type as InnoDB, you can use transactions. You will need set AUTOCOMMIT=0, and after you can issue COMMIT or ROLLBACK at the end of query or session to submit or cancel a transaction. ROLLBACK — will undo the changes that you have made
rake db:rollback STEP=1 Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back. For example: rake db:rollback STEP=5 Will also rollback all the migration that happened later (4, 3, 2 and also 1). To … Read more
It would not be a good idea to rollback sequences. Imagine two transactions happening at the same time, each of which uses the sequence for a unique id. If the second transaction commits and the first transaction rolls back, then the second inserted a row with “2” while the first rolls the sequence back to … Read more
Download and install Team Foundation Power Tools. Open up the Visual Studio command prompt Navigate to the directory on the file system that TFS is mapped to. If you don’t do this you’ll get an “Unable to determine the workspace” error when you try to roll back Make sure everything else is checked in or … Read more
What is described by skwllsp can be be done in a dynamic view through the use of extended pathnames cd m:/myDynamicView/MyVob/path/to/file cleartool lsvtree myFile cleartool checkout -c “cancel co” myFile copy myFile@@/main/xx myFile cleartool checkin -nc myFile with xx being the version number you want to restore. But should you have made multiple checkins, including … Read more
Dispose method for transaction class performs a rollback while Oracle’s class doesn’t. So from transaction’s perspective it’s implementation dependent. The using statement for the connection object on the other hand would either close the connection to the database or return the connection to the pool after resetting it. In either case, the outstanding transactions should … Read more
rake db:rollback STEP=1 Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back. For example: rake db:rollback STEP=5 Will also rollback all the migration that happened later (4, 3, 2 and also 1). To … Read more
You can use 13.6.7.2. DECLARE … HANDLER Syntax in the following way: DELIMITER $$ CREATE PROCEDURE `sp_fail`() BEGIN DECLARE `_rollback` BOOL DEFAULT 0; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET `_rollback` = 1; START TRANSACTION; INSERT INTO `tablea` (`date`) VALUES (NOW()); INSERT INTO `tableb` (`date`) VALUES (NOW()); INSERT INTO `tablec` (`date`) VALUES (NOW()); — FAIL IF … Read more
You won’t always be able to simply generate the migration to already have the code you want. You can create an empty migration and then populate it with the code you need. You can find information about how to accomplish different tasks in a migration here: http://api.rubyonrails.org/classes/ActiveRecord/Migration.html More specifically, you can see how to drop … Read more