transactions

问题 I develop one application using VB.net (200%) that connects to MS-Access Database, I use TableAdapter and Dataset for connection to the Access DB file. I need to implement a simple transaction method (commit, rollback) in saving to the DB? Is there a way to do that without the need to use inline SQL statement? Thanks, 回答1: As I read Microsoft Jet (Access DB Engine) supports transactions. So you can create a transaction like this (example from CodeProject): SqlConnection db = new SqlConnection

问题 I develop one application using VB.net (200%) that connects to MS-Access Database, I use TableAdapter and Dataset for connection to the Access DB file. I need to implement a simple transaction method (commit, rollback) in saving to the DB? Is there a way to do that without the need to use inline SQL statement? Thanks, 回答1: As I read Microsoft Jet (Access DB Engine) supports transactions. So you can create a transaction like this (example from CodeProject): SqlConnection db = new SqlConnection

问题 I have been able to use CakePHP's saveAll method to simultaneously create 'Members' and enroll them in an 'Event' (creating the HABTM link record), which is awesome. For example, this code creates two new 'Members' and adds a record for each of them to the 'EventsMember' table, enrolling them 'Event' 10: $data = array( '0' => array( 'Member' => array('email' => 'nobody@nowhere.com'), 'Event' => array('id' => 10) ), '1' => array( 'Member' => array('email' => 'somebody@nowhere.com'), 'Event' =>

问题 I will explain problem with an example: There is two table in my database, named entry, tags There is a column named ID_ENTRY in both table. When I add a record to table, entry, I have to take the ID_ENTRY of last added record and add it to table, tags. How can I do it? 回答1: Immediatly after executing the insert statement on first table, you should query @@IDENTITY doing "SELECT @@identity". That will retrieve the last autogenerated ID... and then just insert it on the second table. If you

问题 Question What is the benefit of applying locks to the below statement? Similarly, what issue would we see if we didn't include these hints? i.e. Do they prevent a race condition, improve performance, or maybe something else? Asking as perhaps they're included to prevent some issue I've not considered rather than the race condition I'd assumed. NB: This is an overflow from a question asked here: SQL Threadsafe UPDATE TOP 1 for FIFO Queue The Statement In Question WITH nextRecordToProcess AS (

问题 I have a loop where I call stored procedure with different parameter value. Next call cmd.ExecuteNonQuery(); I use transaction to save all or rollback, and checkBox2 - save always. I found one problem and I can't find solution. After first problem when catch block is fired transaction object loses its connection. t.connection is null! Everything is good but transaction object is without connection at start it has! try { while (!sr.EndOfStream) { strLine.Remove(0, strLine.Length); //c = sr

问题 I want to create a user with a role in the same transaction but i have an issue with the implementation. In order to use the userStore in the transaction and have it not save the changes automatically and ignore my transaction i had to turn off AutoSaveChanges. This makes it so it will wait until i call save changes. This works fine but because the userstore now does not return the userId when i call manager.Create due to this being off I dont have an Id to pass into userManager.AddToRole. Is

问题 Idea I have a processing method which takes in a list of items and processes them asynchronously using external web service. The process steps also persist data while processing. At the end of whole process, I want to persist the whole process along with each processed results as well. Problem I convert each item in the list into CompletableFuture and run a processing task on them, and put them back into an array of futures. Now using its .ofAll method (in sequence method) to complete future

问题 Can MySqlBulkLoader be used with a transaction? I don't see a way to explicitly attach a transaction to an instance of the loader. Is there another way? 回答1: As stated here by member of MySQL documentation team: It's not atomic. The records loaded prior to the error will be in the table. Work arround is to import data to dedicated table and then execute INSERT INTO ... SELECT ... which will be atomic operation. On huge data sets this is potential problem becasue of long transaction. 回答2: The

问题 Can MySqlBulkLoader be used with a transaction? I don't see a way to explicitly attach a transaction to an instance of the loader. Is there another way? 回答1: As stated here by member of MySQL documentation team: It's not atomic. The records loaded prior to the error will be in the table. Work arround is to import data to dedicated table and then execute INSERT INTO ... SELECT ... which will be atomic operation. On huge data sets this is potential problem becasue of long transaction. 回答2: The