diff options
Diffstat (limited to 'lib/sqlalchemy/sql/default_comparator.py')
| -rw-r--r-- | lib/sqlalchemy/sql/default_comparator.py | 544 |
1 files changed, 260 insertions, 284 deletions
diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py index 4f53e2979..bb9e53aae 100644 --- a/lib/sqlalchemy/sql/default_comparator.py +++ b/lib/sqlalchemy/sql/default_comparator.py @@ -9,8 +9,8 @@ """ from .. import exc, util -from . import operators from . import type_api +from . import operators from .elements import BindParameter, True_, False_, BinaryExpression, \ Null, _const_expr, _clause_element_as_expr, \ ClauseList, ColumnElement, TextClause, UnaryExpression, \ @@ -18,294 +18,270 @@ from .elements import BindParameter, True_, False_, BinaryExpression, \ from .selectable import SelectBase, Alias, Selectable, ScalarSelect -class _DefaultColumnComparator(operators.ColumnOperators): - """Defines comparison and math operations. - - See :class:`.ColumnOperators` and :class:`.Operators` for descriptions - of all operations. - - """ - - @util.memoized_property - def type(self): - return self.expr.type - - def operate(self, op, *other, **kwargs): - o = self.operators[op.__name__] - return o[0](self, self.expr, op, *(other + o[1:]), **kwargs) - - def reverse_operate(self, op, other, **kwargs): - o = self.operators[op.__name__] - return o[0](self, self.expr, op, other, - reverse=True, *o[1:], **kwargs) - - def _adapt_expression(self, op, other_comparator): - """evaluate the return type of <self> <op> <othertype>, - and apply any adaptations to the given operator. - - This method determines the type of a resulting binary expression - given two source types and an operator. For example, two - :class:`.Column` objects, both of the type :class:`.Integer`, will - produce a :class:`.BinaryExpression` that also has the type - :class:`.Integer` when compared via the addition (``+``) operator. - However, using the addition operator with an :class:`.Integer` - and a :class:`.Date` object will produce a :class:`.Date`, assuming - "days delta" behavior by the database (in reality, most databases - other than Postgresql don't accept this particular operation). - - The method returns a tuple of the form <operator>, <type>. - The resulting operator and type will be those applied to the - resulting :class:`.BinaryExpression` as the final operator and the - right-hand side of the expression. - - Note that only a subset of operators make usage of - :meth:`._adapt_expression`, - including math operators and user-defined operators, but not - boolean comparison or special SQL keywords like MATCH or BETWEEN. - - """ - return op, other_comparator.type - - def _boolean_compare(self, expr, op, obj, negate=None, reverse=False, - _python_is_types=(util.NoneType, bool), - **kwargs): - - if isinstance(obj, _python_is_types + (Null, True_, False_)): - - # allow x ==/!= True/False to be treated as a literal. - # this comes out to "== / != true/false" or "1/0" if those - # constants aren't supported and works on all platforms - if op in (operators.eq, operators.ne) and \ - isinstance(obj, (bool, True_, False_)): - return BinaryExpression(expr, - _literal_as_text(obj), - op, - type_=type_api.BOOLEANTYPE, - negate=negate, modifiers=kwargs) - else: - # all other None/True/False uses IS, IS NOT - if op in (operators.eq, operators.is_): - return BinaryExpression(expr, _const_expr(obj), - operators.is_, - negate=operators.isnot) - elif op in (operators.ne, operators.isnot): - return BinaryExpression(expr, _const_expr(obj), - operators.isnot, - negate=operators.is_) - else: - raise exc.ArgumentError( - "Only '=', '!=', 'is_()', 'isnot()' operators can " - "be used with None/True/False") - else: - obj = self._check_literal(expr, op, obj) +def _boolean_compare(expr, op, obj, negate=None, reverse=False, + _python_is_types=(util.NoneType, bool), + result_type = None, + **kwargs): - if reverse: - return BinaryExpression(obj, - expr, - op, - type_=type_api.BOOLEANTYPE, - negate=negate, modifiers=kwargs) - else: + if result_type is None: + result_type = type_api.BOOLEANTYPE + + if isinstance(obj, _python_is_types + (Null, True_, False_)): + + # allow x ==/!= True/False to be treated as a literal. + # this comes out to "== / != true/false" or "1/0" if those + # constants aren't supported and works on all platforms + if op in (operators.eq, operators.ne) and \ + isinstance(obj, (bool, True_, False_)): return BinaryExpression(expr, - obj, + _literal_as_text(obj), op, - type_=type_api.BOOLEANTYPE, + type_=result_type, negate=negate, modifiers=kwargs) - - def _binary_operate(self, expr, op, obj, reverse=False, result_type=None, - **kw): - obj = self._check_literal(expr, op, obj) - - if reverse: - left, right = obj, expr - else: - left, right = expr, obj - - if result_type is None: - op, result_type = left.comparator._adapt_expression( - op, right.comparator) - - return BinaryExpression(left, right, op, type_=result_type) - - def _conjunction_operate(self, expr, op, other, **kw): - if op is operators.and_: - return and_(expr, other) - elif op is operators.or_: - return or_(expr, other) else: - raise NotImplementedError() - - def _scalar(self, expr, op, fn, **kw): - return fn(expr) - - def _in_impl(self, expr, op, seq_or_selectable, negate_op, **kw): - seq_or_selectable = _clause_element_as_expr(seq_or_selectable) - - if isinstance(seq_or_selectable, ScalarSelect): - return self._boolean_compare(expr, op, seq_or_selectable, - negate=negate_op) - elif isinstance(seq_or_selectable, SelectBase): - - # TODO: if we ever want to support (x, y, z) IN (select x, - # y, z from table), we would need a multi-column version of - # as_scalar() to produce a multi- column selectable that - # does not export itself as a FROM clause - - return self._boolean_compare( - expr, op, seq_or_selectable.as_scalar(), - negate=negate_op, **kw) - elif isinstance(seq_or_selectable, (Selectable, TextClause)): - return self._boolean_compare(expr, op, seq_or_selectable, - negate=negate_op, **kw) - elif isinstance(seq_or_selectable, ClauseElement): - raise exc.InvalidRequestError( - 'in_() accepts' - ' either a list of expressions ' - 'or a selectable: %r' % seq_or_selectable) - - # Handle non selectable arguments as sequences - args = [] - for o in seq_or_selectable: - if not _is_literal(o): - if not isinstance(o, operators.ColumnOperators): - raise exc.InvalidRequestError( - 'in_() accepts' - ' either a list of expressions ' - 'or a selectable: %r' % o) - elif o is None: - o = Null() + # all other None/True/False uses IS, IS NOT + if op in (operators.eq, operators.is_): + return BinaryExpression(expr, _const_expr(obj), + operators.is_, + negate=operators.isnot) + elif op in (operators.ne, operators.isnot): + return BinaryExpression(expr, _const_expr(obj), + operators.isnot, + negate=operators.is_) else: - o = expr._bind_param(op, o) - args.append(o) - if len(args) == 0: - - # Special case handling for empty IN's, behave like - # comparison against zero row selectable. We use != to - # build the contradiction as it handles NULL values - # appropriately, i.e. "not (x IN ())" should not return NULL - # values for x. - - util.warn('The IN-predicate on "%s" was invoked with an ' - 'empty sequence. This results in a ' - 'contradiction, which nonetheless can be ' - 'expensive to evaluate. Consider alternative ' - 'strategies for improved performance.' % expr) - if op is operators.in_op: - return expr != expr - else: - return expr == expr - - return self._boolean_compare(expr, op, - ClauseList(*args).self_group(against=op), - negate=negate_op) - - def _unsupported_impl(self, expr, op, *arg, **kw): - raise NotImplementedError("Operator '%s' is not supported on " - "this expression" % op.__name__) - - def _inv_impl(self, expr, op, **kw): - """See :meth:`.ColumnOperators.__inv__`.""" - if hasattr(expr, 'negation_clause'): - return expr.negation_clause + raise exc.ArgumentError( + "Only '=', '!=', 'is_()', 'isnot()' operators can " + "be used with None/True/False") + else: + obj = _check_literal(expr, op, obj) + + if reverse: + return BinaryExpression(obj, + expr, + op, + type_=result_type, + negate=negate, modifiers=kwargs) + else: + return BinaryExpression(expr, + obj, + op, + type_=result_type, + negate=negate, modifiers=kwargs) + + +def _binary_operate(expr, op, obj, reverse=False, result_type=None, + **kw): + obj = _check_literal(expr, op, obj) + + if reverse: + left, right = obj, expr + else: + left, right = expr, obj + + if result_type is None: + op, result_type = left.comparator._adapt_expression( + op, right.comparator) + + return BinaryExpression( + left, right, op, type_=result_type, modifiers=kw) + + +def _conjunction_operate(expr, op, other, **kw): + if op is operators.and_: + return and_(expr, other) + elif op is operators.or_: + return or_(expr, other) + else: + raise NotImplementedError() + + +def _scalar(expr, op, fn, **kw): + return fn(expr) + + +def _in_impl(expr, op, seq_or_selectable, negate_op, **kw): + seq_or_selectable = _clause_element_as_expr(seq_or_selectable) + + if isinstance(seq_or_selectable, ScalarSelect): + return _boolean_compare(expr, op, seq_or_selectable, + negate=negate_op) + elif isinstance(seq_or_selectable, SelectBase): + + # TODO: if we ever want to support (x, y, z) IN (select x, + # y, z from table), we would need a multi-column version of + # as_scalar() to produce a multi- column selectable that + # does not export itself as a FROM clause + + return _boolean_compare( + expr, op, seq_or_selectable.as_scalar(), + negate=negate_op, **kw) + elif isinstance(seq_or_selectable, (Selectable, TextClause)): + return _boolean_compare(expr, op, seq_or_selectable, + negate=negate_op, **kw) + elif isinstance(seq_or_selectable, ClauseElement): + raise exc.InvalidRequestError( + 'in_() accepts' + ' either a list of expressions ' + 'or a selectable: %r' % seq_or_selectable) + + # Handle non selectable arguments as sequences + args = [] + for o in seq_or_selectable: + if not _is_literal(o): + if not isinstance(o, operators.ColumnOperators): + raise exc.InvalidRequestError( + 'in_() accepts' + ' either a list of expressions ' + 'or a selectable: %r' % o) + elif o is None: + o = Null() else: - return expr._negate() - - def _neg_impl(self, expr, op, **kw): - """See :meth:`.ColumnOperators.__neg__`.""" - return UnaryExpression(expr, operator=operators.neg) - - def _match_impl(self, expr, op, other, **kw): - """See :meth:`.ColumnOperators.match`.""" - return self._boolean_compare( - expr, operators.match_op, - self._check_literal( - expr, operators.match_op, other), - **kw) - - def _distinct_impl(self, expr, op, **kw): - """See :meth:`.ColumnOperators.distinct`.""" - return UnaryExpression(expr, operator=operators.distinct_op, - type_=expr.type) - - def _between_impl(self, expr, op, cleft, cright, **kw): - """See :meth:`.ColumnOperators.between`.""" - return BinaryExpression( - expr, - ClauseList( - self._check_literal(expr, operators.and_, cleft), - self._check_literal(expr, operators.and_, cright), - operator=operators.and_, - group=False, group_contents=False), - op, - negate=operators.notbetween_op - if op is operators.between_op - else operators.between_op, - modifiers=kw) - - def _collate_impl(self, expr, op, other, **kw): - return collate(expr, other) - - # a mapping of operators with the method they use, along with - # their negated operator for comparison operators - operators = { - "and_": (_conjunction_operate,), - "or_": (_conjunction_operate,), - "inv": (_inv_impl,), - "add": (_binary_operate,), - "mul": (_binary_operate,), - "sub": (_binary_operate,), - "div": (_binary_operate,), - "mod": (_binary_operate,), - "truediv": (_binary_operate,), - "custom_op": (_binary_operate,), - "concat_op": (_binary_operate,), - "lt": (_boolean_compare, operators.ge), - "le": (_boolean_compare, operators.gt), - "ne": (_boolean_compare, operators.eq), - "gt": (_boolean_compare, operators.le), - "ge": (_boolean_compare, operators.lt), - "eq": (_boolean_compare, operators.ne), - "like_op": (_boolean_compare, operators.notlike_op), - "ilike_op": (_boolean_compare, operators.notilike_op), - "notlike_op": (_boolean_compare, operators.like_op), - "notilike_op": (_boolean_compare, operators.ilike_op), - "contains_op": (_boolean_compare, operators.notcontains_op), - "startswith_op": (_boolean_compare, operators.notstartswith_op), - "endswith_op": (_boolean_compare, operators.notendswith_op), - "desc_op": (_scalar, UnaryExpression._create_desc), - "asc_op": (_scalar, UnaryExpression._create_asc), - "nullsfirst_op": (_scalar, UnaryExpression._create_nullsfirst), - "nullslast_op": (_scalar, UnaryExpression._create_nullslast), - "in_op": (_in_impl, operators.notin_op), - "notin_op": (_in_impl, operators.in_op), - "is_": (_boolean_compare, operators.is_), - "isnot": (_boolean_compare, operators.isnot), - "collate": (_collate_impl,), - "match_op": (_match_impl,), - "distinct_op": (_distinct_impl,), - "between_op": (_between_impl, ), - "notbetween_op": (_between_impl, ), - "neg": (_neg_impl,), - "getitem": (_unsupported_impl,), - "lshift": (_unsupported_impl,), - "rshift": (_unsupported_impl,), - } - - def _check_literal(self, expr, operator, other): - if isinstance(other, (ColumnElement, TextClause)): - if isinstance(other, BindParameter) and \ - other.type._isnull: - other = other._clone() - other.type = expr.type - return other - elif hasattr(other, '__clause_element__'): - other = other.__clause_element__() - elif isinstance(other, type_api.TypeEngine.Comparator): - other = other.expr - - if isinstance(other, (SelectBase, Alias)): - return other.as_scalar() - elif not isinstance(other, (ColumnElement, TextClause)): - return expr._bind_param(operator, other) + o = expr._bind_param(op, o) + args.append(o) + if len(args) == 0: + + # Special case handling for empty IN's, behave like + # comparison against zero row selectable. We use != to + # build the contradiction as it handles NULL values + # appropriately, i.e. "not (x IN ())" should not return NULL + # values for x. + + util.warn('The IN-predicate on "%s" was invoked with an ' + 'empty sequence. This results in a ' + 'contradiction, which nonetheless can be ' + 'expensive to evaluate. Consider alternative ' + 'strategies for improved performance.' % expr) + if op is operators.in_op: + return expr != expr else: - return other + return expr == expr + + return _boolean_compare(expr, op, + ClauseList(*args).self_group(against=op), + negate=negate_op) + + +def _unsupported_impl(expr, op, *arg, **kw): + raise NotImplementedError("Operator '%s' is not supported on " + "this expression" % op.__name__) + + +def _inv_impl(expr, op, **kw): + """See :meth:`.ColumnOperators.__inv__`.""" + if hasattr(expr, 'negation_clause'): + return expr.negation_clause + else: + return expr._negate() + + +def _neg_impl(expr, op, **kw): + """See :meth:`.ColumnOperators.__neg__`.""" + return UnaryExpression(expr, operator=operators.neg) + + +def _match_impl(expr, op, other, **kw): + """See :meth:`.ColumnOperators.match`.""" + + return _boolean_compare( + expr, operators.match_op, + _check_literal( + expr, operators.match_op, other), + result_type=type_api.MATCHTYPE, + negate=operators.notmatch_op + if op is operators.match_op else operators.match_op, + **kw + ) + + +def _distinct_impl(expr, op, **kw): + """See :meth:`.ColumnOperators.distinct`.""" + return UnaryExpression(expr, operator=operators.distinct_op, + type_=expr.type) + + +def _between_impl(expr, op, cleft, cright, **kw): + """See :meth:`.ColumnOperators.between`.""" + return BinaryExpression( + expr, + ClauseList( + _check_literal(expr, operators.and_, cleft), + _check_literal(expr, operators.and_, cright), + operator=operators.and_, + group=False, group_contents=False), + op, + negate=operators.notbetween_op + if op is operators.between_op + else operators.between_op, + modifiers=kw) + + +def _collate_impl(expr, op, other, **kw): + return collate(expr, other) + +# a mapping of operators with the method they use, along with +# their negated operator for comparison operators +operator_lookup = { + "and_": (_conjunction_operate,), + "or_": (_conjunction_operate,), + "inv": (_inv_impl,), + "add": (_binary_operate,), + "mul": (_binary_operate,), + "sub": (_binary_operate,), + "div": (_binary_operate,), + "mod": (_binary_operate,), + "truediv": (_binary_operate,), + "custom_op": (_binary_operate,), + "concat_op": (_binary_operate,), + "lt": (_boolean_compare, operators.ge), + "le": (_boolean_compare, operators.gt), + "ne": (_boolean_compare, operators.eq), + "gt": (_boolean_compare, operators.le), + "ge": (_boolean_compare, operators.lt), + "eq": (_boolean_compare, operators.ne), + "like_op": (_boolean_compare, operators.notlike_op), + "ilike_op": (_boolean_compare, operators.notilike_op), + "notlike_op": (_boolean_compare, operators.like_op), + "notilike_op": (_boolean_compare, operators.ilike_op), + "contains_op": (_boolean_compare, operators.notcontains_op), + "startswith_op": (_boolean_compare, operators.notstartswith_op), + "endswith_op": (_boolean_compare, operators.notendswith_op), + "desc_op": (_scalar, UnaryExpression._create_desc), + "asc_op": (_scalar, UnaryExpression._create_asc), + "nullsfirst_op": (_scalar, UnaryExpression._create_nullsfirst), + "nullslast_op": (_scalar, UnaryExpression._create_nullslast), + "in_op": (_in_impl, operators.notin_op), + "notin_op": (_in_impl, operators.in_op), + "is_": (_boolean_compare, operators.is_), + "isnot": (_boolean_compare, operators.isnot), + "collate": (_collate_impl,), + "match_op": (_match_impl,), + "notmatch_op": (_match_impl,), + "distinct_op": (_distinct_impl,), + "between_op": (_between_impl, ), + "notbetween_op": (_between_impl, ), + "neg": (_neg_impl,), + "getitem": (_unsupported_impl,), + "lshift": (_unsupported_impl,), + "rshift": (_unsupported_impl,), +} + + +def _check_literal(expr, operator, other): + if isinstance(other, (ColumnElement, TextClause)): + if isinstance(other, BindParameter) and \ + other.type._isnull: + other = other._clone() + other.type = expr.type + return other + elif hasattr(other, '__clause_element__'): + other = other.__clause_element__() + elif isinstance(other, type_api.TypeEngine.Comparator): + other = other.expr + + if isinstance(other, (SelectBase, Alias)): + return other.as_scalar() + elif not isinstance(other, (ColumnElement, TextClause)): + return expr._bind_param(operator, other) + else: + return other + |