Question

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I have very simple database with PostgreSQL 9.2.1. When i insert something with Doctrine2 by using this method:

$em->persist($entity);
$em->flush();

If I get an error

-means record NOT inserted-

it still adds 1 to my primary key. So if i refresh the page 50 times, it says auto increment value is set to 50. How can I prevent this? If record not insterted than why primary key increases. This is very critical because it uses indexes for nothing and the number keep going bigger.

I have no idea what it came from and why, so, i did not tried anything. Very stuck at this point.

Answer 1

Doctrine2 uses transactions to complete it’s tasks.

Each time a Doctrine flushes its changes to the database, it opens a transaction, each record is prepared and then the commit will action the changes all at once.

During this process, the records that require an auto_increment ID are assigned. If the record then fails during the commit phase, the records aren’t added, but the auto increment has issued that ID.

You can read more about Transactions here: http://www.postgresql.org/docs/current/static/tutorial-transactions.html

Note: This is also the same for MySQL and I’m sure the same for many other RDBMS.