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-rw-r--r--lib/sqlalchemy/sql/elements.py24
1 files changed, 10 insertions, 14 deletions
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index 444273e67..4d5bb9476 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -1617,10 +1617,10 @@ class Null(ColumnElement):
return type_api.NULLTYPE
@classmethod
- def _singleton(cls):
+ def _instance(cls):
"""Return a constant :class:`.Null` construct."""
- return NULL
+ return Null()
def compare(self, other):
return isinstance(other, Null)
@@ -1641,11 +1641,11 @@ class False_(ColumnElement):
return type_api.BOOLEANTYPE
def _negate(self):
- return TRUE
+ return True_()
@classmethod
- def _singleton(cls):
- """Return a constant :class:`.False_` construct.
+ def _instance(cls):
+ """Return a :class:`.False_` construct.
E.g.::
@@ -1679,7 +1679,7 @@ class False_(ColumnElement):
"""
- return FALSE
+ return False_()
def compare(self, other):
return isinstance(other, False_)
@@ -1700,17 +1700,17 @@ class True_(ColumnElement):
return type_api.BOOLEANTYPE
def _negate(self):
- return FALSE
+ return False_()
@classmethod
def _ifnone(cls, other):
if other is None:
- return cls._singleton()
+ return cls._instance()
else:
return other
@classmethod
- def _singleton(cls):
+ def _instance(cls):
"""Return a constant :class:`.True_` construct.
E.g.::
@@ -1745,15 +1745,11 @@ class True_(ColumnElement):
"""
- return TRUE
+ return True_()
def compare(self, other):
return isinstance(other, True_)
-NULL = Null()
-FALSE = False_()
-TRUE = True_()
-
class ClauseList(ClauseElement):
"""Describe a list of clauses, separated by an operator.