diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/howto/writing-migrations.txt | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/howto/writing-migrations.txt b/docs/howto/writing-migrations.txt index d092aec6e8..3a818a0fda 100644 --- a/docs/howto/writing-migrations.txt +++ b/docs/howto/writing-migrations.txt @@ -336,7 +336,7 @@ model, the default migration will delete the existing table and create a new one, losing the existing relations. To avoid this, you can use :class:`.SeparateDatabaseAndState` to rename the existing table to the new table name while telling the migration autodetector that the new model has -been created. You can check the existing table name through +been created. You can check the existing table name and constraint name through :djadmin:`sqlmigrate` or :djadmin:`dbshell`. You can check the new table name with the through model's ``_meta.db_table`` property. Your new ``through`` model should use the same names for the ``ForeignKey``\s as Django did. Also if @@ -394,6 +394,14 @@ For example, if we had a ``Book`` model with a ``ManyToManyField`` linking to ), ), ], + options={ + "constraints": [ + models.UniqueConstraint( + fields=["author", "book"], + name="unique_author_book", + ) + ], + }, ), migrations.AlterField( model_name="book", |