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Fixed #31455 -- Added support for deferrable exclusion constraints on PostgreSQL.

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Ian Foote 2020-04-12 11:43:16 +01:00 • committed by Mariusz Felisiak
parent 5d2f5dd4cc
commit b4068bc656
4 changed files with 145 additions and 7 deletions
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27
django/contrib/postgres/constraints.py
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@ -1,5 +1,5 @@
from django.db.backends.ddl_references import Statement, Table
from django.db.models import F, Q
from django.db.models import Deferrable, F, Q
from django.db.models.constraints import BaseConstraint
from django.db.models.sql import Query
@ -7,9 +7,12 @@ __all__ = ['ExclusionConstraint']
class ExclusionConstraint(BaseConstraint):
template = 'CONSTRAINT %(name)s EXCLUDE USING %(index_type)s (%(expressions)s)%(where)s'
template = 'CONSTRAINT %(name)s EXCLUDE USING %(index_type)s (%(expressions)s)%(where)s%(deferrable)s'
def __init__(self, *, name, expressions, index_type=None, condition=None):
def __init__(
self, *, name, expressions, index_type=None, condition=None,
deferrable=None,
):
if index_type and index_type.lower() not in {'gist', 'spgist'}:
raise ValueError(
'Exclusion constraints only support GiST or SP-GiST indexes.'
@ -28,9 +31,18 @@ class ExclusionConstraint(BaseConstraint):
raise ValueError(
'ExclusionConstraint.condition must be a Q instance.'
)
if condition and deferrable:
raise ValueError(
'ExclusionConstraint with conditions cannot be deferred.'
)
if not isinstance(deferrable, (type(None), Deferrable)):
raise ValueError(
'ExclusionConstraint.deferrable must be a Deferrable instance.'
)
self.expressions = expressions
self.index_type = index_type or 'GIST'
self.condition = condition
self.deferrable = deferrable
super().__init__(name=name)
def _get_expression_sql(self, compiler, connection, query):
@ -60,6 +72,7 @@ class ExclusionConstraint(BaseConstraint):
'index_type': self.index_type,
'expressions': ', '.join(expressions),
'where': ' WHERE (%s)' % condition if condition else '',
'deferrable': schema_editor._deferrable_constraint_sql(self.deferrable),
}
def create_sql(self, model, schema_editor):
@ -83,6 +96,8 @@ class ExclusionConstraint(BaseConstraint):
kwargs['condition'] = self.condition
if self.index_type.lower() != 'gist':
kwargs['index_type'] = self.index_type
if self.deferrable:
kwargs['deferrable'] = self.deferrable
return path, args, kwargs
def __eq__(self, other):
@ -91,14 +106,16 @@ class ExclusionConstraint(BaseConstraint):
self.name == other.name and
self.index_type == other.index_type and
self.expressions == other.expressions and
self.condition == other.condition
self.condition == other.condition and
self.deferrable == other.deferrable
)
return super().__eq__(other)
def __repr__(self):
return '<%s: index_type=%s, expressions=%s%s>' % (
return '<%s: index_type=%s, expressions=%s%s%s>' % (
self.__class__.__qualname__,
self.index_type,
self.expressions,
'' if self.condition is None else ', condition=%s' % self.condition,
'' if self.deferrable is None else ', deferrable=%s' % self.deferrable,
)