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Diffstat (limited to 'docs/ref/models')
| -rw-r--r-- | docs/ref/models/constraints.txt | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/docs/ref/models/constraints.txt b/docs/ref/models/constraints.txt index e3b682d1c5..c675903db6 100644 --- a/docs/ref/models/constraints.txt +++ b/docs/ref/models/constraints.txt @@ -69,10 +69,30 @@ constraint. ``UniqueConstraint`` ==================== -.. class:: UniqueConstraint(*, fields, name, condition=None, deferrable=None, include=None, opclasses=()) +.. class:: UniqueConstraint(*expressions, fields=(), name=None, condition=None, deferrable=None, include=None, opclasses=()) Creates a unique constraint in the database. +``expressions`` +--------------- + +.. attribute:: UniqueConstraint.expressions + +.. versionadded:: 4.0 + +Positional argument ``*expressions`` allows creating functional unique +constraints on expressions and database functions. + +For example:: + + UniqueConstraint(Lower('name').desc(), 'category', name='unique_lower_name_category') + +creates a unique constraint on the lowercased value of the ``name`` field in +descending order and the ``category`` field in the default ascending order. + +Functional unique constraints have the same database restrictions as +:attr:`Index.expressions`. + ``fields`` ---------- |