diff options
Diffstat (limited to 'django/db/models/sql')
| -rw-r--r-- | django/db/models/sql/__init__.py | 4 | ||||
| -rw-r--r-- | django/db/models/sql/where.py | 30 |
2 files changed, 28 insertions, 6 deletions
diff --git a/django/db/models/sql/__init__.py b/django/db/models/sql/__init__.py index 2956e047b1..dd31a6ea9e 100644 --- a/django/db/models/sql/__init__.py +++ b/django/db/models/sql/__init__.py @@ -1,6 +1,6 @@ from django.db.models.sql.query import * # NOQA from django.db.models.sql.query import Query from django.db.models.sql.subqueries import * # NOQA -from django.db.models.sql.where import AND, OR +from django.db.models.sql.where import AND, OR, XOR -__all__ = ["Query", "AND", "OR"] +__all__ = ["Query", "AND", "OR", "XOR"] diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py index 532780fd98..8e3ad74d65 100644 --- a/django/db/models/sql/where.py +++ b/django/db/models/sql/where.py @@ -1,14 +1,19 @@ """ Code to manage the creation and SQL rendering of 'where' constraints. """ +import operator +from functools import reduce from django.core.exceptions import EmptyResultSet +from django.db.models.expressions import Case, When +from django.db.models.lookups import Exact from django.utils import tree from django.utils.functional import cached_property # Connection types AND = "AND" OR = "OR" +XOR = "XOR" class WhereNode(tree.Node): @@ -39,10 +44,12 @@ class WhereNode(tree.Node): if not self.contains_aggregate: return self, None in_negated = negated ^ self.negated - # If the effective connector is OR and this node contains an aggregate, - # then we need to push the whole branch to HAVING clause. - may_need_split = (in_negated and self.connector == AND) or ( - not in_negated and self.connector == OR + # If the effective connector is OR or XOR and this node contains an + # aggregate, then we need to push the whole branch to HAVING clause. + may_need_split = ( + (in_negated and self.connector == AND) + or (not in_negated and self.connector == OR) + or self.connector == XOR ) if may_need_split and self.contains_aggregate: return None, self @@ -85,6 +92,21 @@ class WhereNode(tree.Node): else: full_needed, empty_needed = 1, len(self.children) + if self.connector == XOR and not connection.features.supports_logical_xor: + # Convert if the database doesn't support XOR: + # a XOR b XOR c XOR ... + # to: + # (a OR b OR c OR ...) AND (a + b + c + ...) == 1 + lhs = self.__class__(self.children, OR) + rhs_sum = reduce( + operator.add, + (Case(When(c, then=1), default=0) for c in self.children), + ) + rhs = Exact(1, rhs_sum) + return self.__class__([lhs, rhs], AND, self.negated).as_sql( + compiler, connection + ) + for child in self.children: try: sql, params = compiler.compile(child) |