From 462ccd9ff18d2e428b20ec3f596391a275472140 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Wed, 15 Aug 2018 17:11:14 -0400 Subject: Add concept of "implicit boolean", treat as native Fixed issue that is closely related to :ticket:`3639` where an expression rendered in a boolean context on a non-native boolean backend would be compared to 1/0 even though it is already an implcitly boolean expression, when :meth:`.ColumnElement.self_group` were used. While this does not affect the user-friendly backends (MySQL, SQLite) it was not handled by Oracle (and possibly SQL Server). Whether or not the expression is implicitly boolean on any database is now determined up front as an additional check to not generate the integer comparison within the compliation of the statement. Fixes: #4320 Change-Id: Iae0a65e5c01bd576e64733c3651e1e1a1a1b240c --- lib/sqlalchemy/sql/elements.py | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'lib/sqlalchemy/sql/elements.py') diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py index 2e8c39f3b..2a6fa323c 100644 --- a/lib/sqlalchemy/sql/elements.py +++ b/lib/sqlalchemy/sql/elements.py @@ -641,6 +641,8 @@ class ColumnElement(operators.ColumnOperators, ClauseElement): """A flag that can be flipped to prevent a column from being resolvable by string label name.""" + _is_implicitly_boolean = False + _alt_names = () def self_group(self, against=None): @@ -1229,6 +1231,7 @@ class TextClause(Executable, ClauseElement): _execution_options = \ Executable._execution_options.union( {'autocommit': PARSE_AUTOCOMMIT}) + _is_implicitly_boolean = False @property def _select_iterable(self): @@ -1813,6 +1816,7 @@ class ClauseList(ClauseElement): self.clauses = [ text_converter(clause) for clause in clauses] + self._is_implicitly_boolean = operators.is_boolean(self.operator) def __iter__(self): return iter(self.clauses) @@ -1915,6 +1919,7 @@ class BooleanClauseList(ClauseList, ColumnElement): self.operator = operator self.group_contents = True self.type = type_api.BOOLEANTYPE + self._is_implicitly_boolean = True return self @classmethod @@ -2923,6 +2928,7 @@ class AsBoolean(UnaryExpression): self.negate = negate self.modifier = None self.wraps_column_expression = True + self._is_implicitly_boolean = element._is_implicitly_boolean def self_group(self, against=None): return self @@ -2950,6 +2956,12 @@ class BinaryExpression(ColumnElement): __visit_name__ = 'binary' + _is_implicitly_boolean = True + """Indicates that any database will know this is a boolean expression + even if the database does not have an explicit boolean datatype. + + """ + def __init__(self, left, right, operator, type_=None, negate=None, modifiers=None): # allow compatibility with libraries that @@ -2962,6 +2974,7 @@ class BinaryExpression(ColumnElement): self.operator = operator self.type = type_api.to_instance(type_) self.negate = negate + self._is_implicitly_boolean = operators.is_boolean(operator) if modifiers is None: self.modifiers = {} @@ -3066,6 +3079,10 @@ class Grouping(ColumnElement): def self_group(self, against=None): return self + @util.memoized_property + def _is_implicitly_boolean(self): + return self.element._is_implicitly_boolean + @property def _key_label(self): return self._label @@ -3550,6 +3567,10 @@ class Label(ColumnElement): def __reduce__(self): return self.__class__, (self.name, self._element, self._type) + @util.memoized_property + def _is_implicitly_boolean(self): + return self.element._is_implicitly_boolean + @util.memoized_property def _allow_label_resolve(self): return self.element._allow_label_resolve -- cgit v1.2.1