Database migration operations¶
All of these operations are available from
the django.contrib.postgres.operations
module.
Creating extension using migrations¶
You can create a PostgreSQL extension in your database using a migration file. This example creates an hstore extension, but the same principles apply for other extensions.
Set up the hstore extension in PostgreSQL before the first CreateModel
or AddField
operation that involves
HStoreField
by adding a migration with
the HStoreExtension
operation.
For example:
from django.contrib.postgres.operations import HStoreExtension
class Migration(migrations.Migration):
...
operations = [
HStoreExtension(),
...
]
For most extensions, this requires a database user with superuser privileges.
If the Django database user doesn’t have the appropriate privileges, you’ll
have to create the extension outside of Django migrations with a user that has
them. In that case, connect to your Django database and run the query
CREATE EXTENSION IF NOT EXISTS hstore;
.
CreateExtension
¶
HStoreExtension
¶
-
class
HStoreExtension
¶ Installs the
hstore
extension and also sets up the connection to interpret hstore data for possible use in subsequent migrations.
Concurrent index operations¶
PostgreSQL supports the CONCURRENTLY
option to CREATE INDEX
and
DROP INDEX
statements to add and remove indexes without locking out writes.
This option is useful for adding or removing an index in a live production
database.
-
class
AddIndexConcurrently
(model_name, index)¶ Like
AddIndex
, but creates an index with theCONCURRENTLY
option. This has a few caveats to be aware of when using this option, see the PostgreSQL documentation of building indexes concurrently.
-
class
RemoveIndexConcurrently
(model_name, name)¶ Like
RemoveIndex
, but removes the index with theCONCURRENTLY
option. This has a few caveats to be aware of when using this option, see the PostgreSQL documentation.
Note
The CONCURRENTLY
option is not supported inside a transaction (see
non-atomic migration).