class NUMBER(sqltypes.Numeric, sqltypes.Integer):
Undocumented
Method | __init__ |
Construct a Numeric. |
Method | adapt |
Produce an "adapted" form of this type, given an "impl" class to work with. |
Class Variable | __visit_name__ |
Undocumented |
Property | _type_affinity |
Return a rudimental 'affinity' value expressing the general class of type. |
Inherited from Numeric
:
Method | bind_processor |
Return a conversion function for processing bind values. |
Method | get_dbapi_type |
Return the corresponding type object from the underlying DB-API, if any. |
Method | literal_processor |
Return a conversion function for processing literal values that are to be rendered directly without using binds. |
Method | result_processor |
Return a conversion function for processing result row values. |
Class Variable | _default_decimal_return_scale |
Undocumented |
Instance Variable | asdecimal |
Undocumented |
Instance Variable | decimal_return_scale |
Undocumented |
Instance Variable | precision |
Undocumented |
Instance Variable | scale |
Undocumented |
Property | _effective_decimal_return_scale |
Undocumented |
Property | _expression_adaptations |
Undocumented |
Property | python_type |
Return the Python type object expected to be returned by instances of this type, if known. |
Inherited from _LookupExpressionAdapter
(via Numeric
):
Class | Comparator |
Undocumented |
Inherited from TypeEngine
(via Numeric
):
Class | Comparator |
Base class for custom comparison operations defined at the type level. See .TypeEngine.comparator_factory . |
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 | with_variant |
Produce a new type object that will utilize the given type when applied to the dialect of the given name. |
Class Variable | hashable |
Flag, if False, means values from this type aren't hashable. |
Class Variable | should_evaluate_none |
If True, the Python constant None is considered to be handled explicitly by this type. |
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 |
Inherited from Traversible
(via Numeric
, TypeEngine
):
Method | get_children |
Return immediate child .visitors.Traversible elements of this .visitors.Traversible . |
Method | __class_getitem__ |
Undocumented |
Inherited from Integer
:
Method | get_dbapi_type |
Return the corresponding type object from the underlying DB-API, if any. |
Method | literal_processor |
Return a conversion function for processing literal values that are to be rendered directly without using binds. |
Property | _expression_adaptations |
Undocumented |
Property | python_type |
Return the Python type object expected to be returned by instances of this type, if known. |
Inherited from _LookupExpressionAdapter
(via Integer
):
Class | Comparator |
Undocumented |
Inherited from TypeEngine
(via Integer
):
Class | Comparator |
Base class for custom comparison operations defined at the type level. See .TypeEngine.comparator_factory . |
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 | bind_processor |
Return a conversion function for processing bind values. |
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 | result_processor |
Return a conversion function for processing result row values. |
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 | hashable |
Flag, if False, means values from this type aren't hashable. |
Class Variable | should_evaluate_none |
If True, the Python constant None is considered to be handled explicitly by this type. |
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 |
Inherited from Traversible
(via Integer
, TypeEngine
):
Method | get_children |
Return immediate child .visitors.Traversible elements of this .visitors.Traversible . |
Method | __class_getitem__ |
Undocumented |
sqlalchemy.types.Numeric.__init__
Construct a Numeric.
When using the Numeric type, care should be taken to ensure that the asdecimal setting is appropriate for the DBAPI in use - when Numeric applies a conversion from Decimal->float or float-> Decimal, this conversion incurs an additional performance overhead for all result columns received.
DBAPIs that return Decimal natively (e.g. psycopg2) will have better accuracy and higher performance with a setting of True, as the native translation to Decimal reduces the amount of floating- point issues at play, and the Numeric type itself doesn't need to apply any further conversions. However, another DBAPI which returns floats natively will incur an additional conversion overhead, and is still subject to floating point data loss - in which case asdecimal=False will at least remove the extra conversion overhead.
Parameters | |
precision | the numeric precision for use in DDL CREATE TABLE. |
scale | the numeric scale for use in DDL CREATE TABLE. |
asdecimal | default True. Return whether or not values should be sent as Python Decimal objects, or as floats. Different DBAPIs send one or the other based on datatypes - the Numeric type will ensure that return values are one or the other across DBAPIs consistently. |
decimal_return_scale | Default scale to use when converting
from floats to Python decimals. Floating point values will typically
be much longer due to decimal inaccuracy, and most floating point
database types don't have a notion of "scale", so by default the
float type looks for the first ten decimal places when converting.
Specifying this value will override that length. Types which
do include an explicit ".scale" value, such as the base
New in version 0.9.0.
|
sqlalchemy.types.TypeEngine.adapt
Produce an "adapted" form of this type, given an "impl" class to work with.
This method is used internally to associate generic types with "implementation" types that are specific to a particular dialect.