defines genericized SQL types, each represented by a subclass of AbstractType. Dialects define further subclasses of these types.
For more information see the SQLAlchemy documentation on types.
given an operator from the sqlalchemy.sql.operators package, translate it to a new operator based on the semantics of this type.
By default, returns the operator unchanged.
Legacy convert_bind_param() compatability method.
This adapter method is provided for user-defined types that implement the older convert_* interface and need to call their super method. These calls are adapted behind the scenes to use the newer callable-based interface via bind_processor().
Compatibility is configured on a case-by-case basis at class definition time by a legacy adapter metaclass. This method is only available and functional if the concrete subclass implements the legacy interface.
Legacy convert_result_value() compatibility method.
This adapter method is provided for user-defined types that implement the older convert_* interface and need to call their super method. These calls are adapted behind the scenes to use the newer callable-based interface via result_processor().
Compatibility is configured on a case-by-case basis at class definition time by a legacy adapter metaclass. This method is only available and functional if the concrete subclass implements the legacy interface.
Return the corresponding type object from the underlying DB-API, if any.
This can be useful for calling setinputsizes(), for example.
return True if the target Python type is 'mutable'.
This allows systems like the ORM to know if an object can be considered 'not changed' by identity alone.
Type to be used in Column statements to store python timedeltas.
If it's possible it uses native engine features to store timedeltas (now it's only PostgreSQL Interval type), if there is no such it fallbacks to DateTime storage with converting from/to timedelta on the fly
Converting is very simple - just use epoch(zero timestamp, 01.01.1970) as base, so if we need to store timedelta = 1 day (24 hours) in database it will be stored as DateTime = '2nd Jan 1970 00:00', see bind_processor and result_processor to actual conversion code
Checks if engine has native implementation of timedelta python type, if so it returns right class to handle it, if there is no native support, it fallback to engine's DateTime implementation class
Construct a new PickleType.
loads the dialect-specific implementation of this type.
by default calls dialect.type_descriptor(self.impl), but can be overridden to provide different behavior.
return a list of classes to test for a match when adapting this type to a dialect-specific type.