Just call get, slice it, etc. and save as usual. The lock is in place through the transaction. ob = MyModel.objects.select_for_update().get(pk=1) Any changes are committed at the end of the transaction (which by default through 1.5 is per-request)
If you are using the ORM, try the with_for_update function: foo = session.query(Foo).filter(Foo.id==1234).with_for_update().one() # this row is now locked foo.name=”bar” session.add(foo) session.commit() # this row is now unlocked
Does it matter which columns I select? No, it doesn’t matter. Even if SELECT 1 FROM table WHERE … FOR UPDATE is used, the query locks all rows that meet where conditions. If the query retrieves rows from a join, and we don’t want to lock rows from all tables involved in the join, but … Read more
The only portable way to achieve consistency between rooms and tags and making sure rooms are never returned after they had been deleted is locking them with SELECT FOR UPDATE. However in some systems locking is a side effect of concurrency control, and you achieve the same results without specifying FOR UPDATE explicitly. To solve … Read more