diff options
Diffstat (limited to 'docs/ref/models')
| -rw-r--r-- | docs/ref/models/querysets.txt | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/docs/ref/models/querysets.txt b/docs/ref/models/querysets.txt index e5d178d34e..d24ac8a859 100644 --- a/docs/ref/models/querysets.txt +++ b/docs/ref/models/querysets.txt @@ -1660,11 +1660,17 @@ generating a ``SELECT ... FOR UPDATE`` SQL statement on supported databases. For example:: + from django.db import transaction + entries = Entry.objects.select_for_update().filter(author=request.user) + with transaction.atomic(): + for entry in entries: + ... -All matched entries will be locked until the end of the transaction block, -meaning that other transactions will be prevented from changing or acquiring -locks on them. +When the queryset is evaluated (``for entry in entries`` in this case), all +matched entries will be locked until the end of the transaction block, meaning +that other transactions will be prevented from changing or acquiring locks on +them. Usually, if another transaction has already acquired a lock on one of the selected rows, the query will block until the lock is released. If this is |