sqlalchemy.dialects.postgresql.asyncpg.AsyncpgJSON

class documentation

class AsyncpgJSON(json.JSON):

Undocumented

Method	`get_dbapi_type`	Return the corresponding type object from the underlying DB-API, if any.
Method	`result_processor`	Return a conversion function for processing result row values.

Inherited from JSON:

Class	`Comparator`	Define comparison operations for `_types.JSON`.
Method	`__init__`	Construct a `_types.JSON` type.
Instance Variable	`astext_type`	Undocumented

Inherited from JSON (via JSON):

Class	`JSONElementType`	Common function for index / path elements in a JSON expression.
Class	`JSONIndexType`	Placeholder for the datatype of a JSON index value.
Class	`JSONIntIndexType`	Placeholder for the datatype of a JSON index value.
Class	`JSONPathType`	Placeholder type for JSON path operations.
Class	`JSONStrIndexType`	Placeholder for the datatype of a JSON index value.
Method	`bind_processor`	Return a conversion function for processing bind values.
Constant	`NULL`	Describe the json value of NULL.
Method	`should_evaluate_none.setter`	Undocumented
Class Variable	`__visit_name__`	Undocumented
Class Variable	`hashable`	Flag, if False, means values from this type aren't hashable.
Instance Variable	`none_as_null`	Undocumented
Property	`_str_impl`	Undocumented
Property	`python_type`	Return the Python type object expected to be returned by instances of this type, if known.
Property	`should_evaluate_none`	Alias of `_types.JSON.none_as_null`

Inherited from TypeEngine (via JSON, JSON):

Method	`adapt`	Produce an "adapted" form of this type, given an "impl" class to work with.
Method	`as_generic`	Return an instance of the generic type corresponding to this type using heuristic rule. The method may be overridden if this heuristic rule is not sufficient.
Method	`bind_expression`	Given a bind value (i.e. a `.BindParameter` instance), return a SQL expression in its place.
Method	`coerce_compared_value`	Suggest a type for a 'coerced' Python value in an expression.
Method	`column_expression`	Given a SELECT column expression, return a wrapping SQL expression.
Method	`compare_against_backend`	Compare this type against the given backend type.
Method	`compare_values`	Compare two values for equality.
Method	`compile`	Produce a string-compiled form of this `.TypeEngine`.
Method	`dialect_impl`	Return a dialect-specific implementation for this `.TypeEngine`.
Method	`evaluates_none`	Return a copy of this type which has the `.should_evaluate_none` flag set to True.
Method	`literal_processor`	Return a conversion function for processing literal values that are to be rendered directly without using binds.
Method	`with_variant`	Produce a new type object that will utilize the given type when applied to the dialect of the given name.
Class Variable	`sort_key_function`	A sorting function that can be passed as the key to sorted.
Static Method	`_to_instance`	Undocumented
Method	`__repr__`	Undocumented
Method	`__str__`	Undocumented
Method	`_cached_bind_processor`	Return a dialect-specific bind processor for this type.
Method	`_cached_custom_processor`	Undocumented
Method	`_cached_literal_processor`	Return a dialect-specific literal processor for this type.
Method	`_cached_result_processor`	Return a dialect-specific result processor for this type.
Method	`_compare_type_affinity`	Undocumented
Method	`_default_dialect`	Undocumented
Method	`_dialect_info`	Return a dialect-specific registry which caches a dialect-specific implementation, bind processing function, and one or more result processing functions.
Method	`_gen_dialect_impl`	Undocumented
Method	`_resolve_for_literal`	adjust this type given a literal Python value that will be stored in a bound parameter.
Method	`_unwrapped_dialect_impl`	Return the 'unwrapped' dialect impl for this type.
Method	`copy`	Undocumented
Method	`copy_value`	Undocumented
Class Variable	`_is_array`	Undocumented
Class Variable	`_is_table_value`	Undocumented
Class Variable	`_is_tuple_type`	Undocumented
Class Variable	`_is_type_decorator`	Undocumented
Class Variable	`_isnull`	Undocumented
Class Variable	`_sqla_type`	Undocumented
Property	`_generic_type_affinity`	Undocumented
Property	`_has_bind_expression`	memoized boolean, check if bind_expression is implemented.
Property	`_has_column_expression`	memoized boolean, check if column_expression is implemented.
Property	`_static_cache_key`	Undocumented
Property	`_type_affinity`	Return a rudimental 'affinity' value expressing the general class of type.

Inherited from Traversible (via JSON, JSON, TypeEngine):

Method	`get_children`	Return immediate child `.visitors.Traversible` elements of this `.visitors.Traversible`.
Method	`__class_getitem__`	Undocumented

def get_dbapi_type(self, dbapi):

overrides sqlalchemy.types.TypeEngine.get_dbapi_type

Return the corresponding type object from the underlying DB-API, if any.

This can be useful for calling setinputsizes(), for example.

def result_processor(self, dialect, coltype):

overrides sqlalchemy.types.JSON.result_processor

Return a conversion function for processing result row values.

Returns a callable which will receive a result row column value as the sole positional argument and will return a value to return to the user.

If processing is not necessary, the method should return None.

Note

This method is only called relative to a dialect specific type object, which is often private to a dialect in use and is not the same type object as the public facing one, which means it's not feasible to subclass a .types.TypeEngine class in order to provide an alternate _types.TypeEngine.result_processor method, unless subclassing the _types.UserDefinedType class explicitly.

To provide alternate behavior for _types.TypeEngine.result_processor, implement a _types.TypeDecorator class and provide an implementation of _types.TypeDecorator.process_result_value.

Parameters
dialect	Dialect instance in use.
coltype	DBAPI coltype argument received in cursor.description.