sqlalchemy.sql.sqltypes.NullType.Comparator

class documentation

class Comparator(TypeEngine.Comparator):

Undocumented

Method _adapt_expression evaluate the return type of <self> <op> <othertype>, and apply any adaptations to the given operator.

Inherited from Comparator:

Method	`operate`	Operate on an argument.
Method	`reverse_operate`	Reverse operate on an argument.
Method	`__clause_element__`	Undocumented
Method	`__init__`	Undocumented
Method	`__reduce__`	Undocumented
Class Variable	`__slots__`	Undocumented
Class Variable	`default_comparator`	Undocumented
Instance Variable	`expr`	Undocumented
Instance Variable	`type`	Undocumented

Inherited from ColumnOperators (via Comparator):

Method	`__add__`	Implement the `+` operator.
Method	`__contains__`	Undocumented
Method	`__div__`	Implement the `/` operator.
Method	`__eq__`	Implement the `==` operator.
Method	`__ge__`	Implement the `>=` operator.
Method	`__getitem__`	Implement the [] operator.
Method	`__gt__`	Implement the `>` operator.
Method	`__le__`	Implement the `<=` operator.
Method	`__lshift__`	implement the << operator.
Method	`__lt__`	Implement the `<` operator.
Method	`__mod__`	Implement the `%` operator.
Method	`__mul__`	Implement the `*` operator.
Method	`__ne__`	Implement the `!=` operator.
Method	`__neg__`	Implement the `-` operator.
Method	`__radd__`	Implement the `+` operator in reverse.
Method	`__rdiv__`	Implement the `/` operator in reverse.
Method	`__rmod__`	Implement the `%` operator in reverse.
Method	`__rmul__`	Implement the `*` operator in reverse.
Method	`__rshift__`	implement the >> operator.
Method	`__rsub__`	Implement the `-` operator in reverse.
Method	`__rtruediv__`	Implement the `//` operator in reverse.
Method	`__sub__`	Implement the `-` operator.
Method	`__truediv__`	Implement the `//` operator.
Method	`all_`	Produce an `_expression.all_` clause against the parent object.
Method	`any_`	Produce an `_expression.any_` clause against the parent object.
Method	`asc`	Produce a `_expression.asc` clause against the parent object.
Method	`between`	Produce a `_expression.between` clause against the parent object, given the lower and upper range.
Method	`collate`	Produce a `_expression.collate` clause against the parent object, given the collation string.
Method	`concat`	Implement the 'concat' operator.
Method	`contains`	Implement the 'contains' operator.
Method	`desc`	Produce a `_expression.desc` clause against the parent object.
Method	`distinct`	Produce a `_expression.distinct` clause against the parent object.
Method	`endswith`	Implement the 'endswith' operator.
Method	`ilike`	Implement the `ilike` operator, e.g. case insensitive LIKE.
Method	`in_`	Implement the `in` operator.
Method	`is_`	Implement the `IS` operator.
Method	`is_distinct_from`	Implement the `IS DISTINCT FROM` operator.
Method	`is_not`	Implement the `IS NOT` operator.
Method	`is_not_distinct_from`	Implement the `IS NOT DISTINCT FROM` operator.
Method	`like`	Implement the `like` operator.
Method	`match`	Implements a database-specific 'match' operator.
Method	`not_ilike`	implement the `NOT ILIKE` operator.
Method	`not_in`	implement the `NOT IN` operator.
Method	`not_like`	implement the `NOT LIKE` operator.
Method	`nulls_first`	Produce a `_expression.nulls_first` clause against the parent object.
Method	`nulls_last`	Produce a `_expression.nulls_last` clause against the parent object.
Method	`regexp_match`	Implements a database-specific 'regexp match' operator.
Method	`regexp_replace`	Implements a database-specific 'regexp replace' operator.
Method	`startswith`	Implement the `startswith` operator.
Class Variable	`timetuple`	Hack, allows datetime objects to be compared on the LHS.

Inherited from Operators (via Comparator, ColumnOperators):

Method	`__and__`	Implement the `&` operator.
Method	`__invert__`	Implement the `~` operator.
Method	`__or__`	Implement the `\|` operator.
Method	`bool_op`	Return a custom boolean operator.
Method	`op`	Produce a generic operator function.

def _adapt_expression(self, op, other_comparator):

overrides sqlalchemy.types.TypeEngine.Comparator._adapt_expression

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 _schema.Column objects, both of the type .Integer, will produce a .BinaryExpression that also has the type .Integer when compared via the addition (+) operator. However, using the addition operator with an .Integer and a .Date object will produce a .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 .BinaryExpression as the final operator and the right-hand side of the expression.

Note that only a subset of operators make usage of ._adapt_expression, including math operators and user-defined operators, but not boolean comparison or special SQL keywords like MATCH or BETWEEN.