class _ColonCast(elements.Cast):
Undocumented
Method | __init__ |
Produce a CAST expression. |
Class Variable | __visit_name__ |
Undocumented |
Instance Variable | clause |
Undocumented |
Instance Variable | type |
Undocumented |
Instance Variable | typeclause |
Undocumented |
Inherited from Cast
:
Class Variable | _traverse_internals |
Undocumented |
Property | _from_objects |
Undocumented |
Property | wrapped_column_expression |
Undocumented |
Inherited from WrapsColumnExpression
(via Cast
):
Method | _dedupe_anon_label_idx |
Undocumented |
Property | _anon_name_label |
Undocumented |
Property | _non_anon_label |
Undocumented |
Property | _tq_label |
Undocumented |
Inherited from ColumnElement
(via Cast
):
Method | cast |
Produce a type cast, i.e. CAST(<expression> AS <type>). |
Method | label |
Produce a column label, i.e. <columnname> AS <name>. |
Method | operate |
Operate on an argument. |
Method | reverse_operate |
Reverse operate on an argument. |
Method | self_group |
Apply a 'grouping' to this _expression.ClauseElement . |
Method | shares_lineage |
Return True if the given _expression.ColumnElement has a common ancestor to this _expression.ColumnElement . |
Class Variable | foreign_keys |
Undocumented |
Class Variable | key |
The 'key' that in some circumstances refers to this object in a Python namespace. |
Class Variable | primary_key |
Undocumented |
Method | __getattr__ |
Undocumented |
Method | _anon_label |
Undocumented |
Method | _bind_param |
Undocumented |
Method | _compare_name_for_result |
Return True if the given column element compares to this one when targeting within a result row. |
Method | _dedupe_anon_label_idx |
label to apply to a column that is anon labeled, but repeated in the SELECT, so that we have to make an "extra anon" label that disambiguates it from the previous appearance. |
Method | _dedupe_anon_tq_label_idx |
Undocumented |
Method | _expression_label |
a suggested label to use in the case that the column has no name, which should be used if possible as the explicit 'AS <label>' where this expression would normally have an anon label. |
Method | _make_proxy |
Create a new _expression.ColumnElement representing this _expression.ColumnElement as it appears in the select list of a descending selectable. |
Method | _negate |
Undocumented |
Method | _proxy_key |
Undocumented |
Method | _tq_key_label |
A label-based version of 'key' that in some circumstances refers to this object in a Python namespace. |
Method | _uncached_proxy_set |
An 'uncached' version of proxy set. |
Method | comparator |
Undocumented |
Class Variable | _allow_label_resolve |
A flag that can be flipped to prevent a column from being resolvable by string label name. |
Class Variable | _alt_names |
Undocumented |
Class Variable | _is_implicitly_boolean |
Undocumented |
Class Variable | _proxies |
Undocumented |
Class Variable | _render_label_in_columns_clause |
No summary |
Class Variable | _tq_label |
The named label that can be used to target this column in a result set in a "table qualified" context. |
Property | _anon_key_label |
Provides a constant 'anonymous key label' for this ColumnElement. |
Property | _anon_name_label |
Provides a constant 'anonymous label' for this ColumnElement. |
Property | _anon_tq_key_label |
Undocumented |
Property | _anon_tq_label |
Undocumented |
Property | _key_label |
legacy; renamed to _tq_key_label |
Property | _label |
legacy; renamed to _tq_label |
Property | _non_anon_label |
the 'name' that naturally applies this element when rendered in SQL. |
Property | _select_iterable |
Undocumented |
Property | anon_key_label |
Undocumented |
Property | anon_label |
Undocumented |
Property | base_columns |
Undocumented |
Property | expression |
Return a column expression. |
Property | proxy_set |
Undocumented |
Inherited from ColumnArgumentOrKeyRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, ColumnArgumentOrKeyRole
, ColumnArgumentRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from StatementOptionRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, StatementOptionRole
, StructuralRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from WhereHavingRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from AllowsLambdaRole
(via Cast
, ColumnElement
, WhereHavingRole
, OnClauseRole
):
Class Variable | allows_lambda |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, WhereHavingRole
, OnClauseRole
, StructuralRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from BinaryElementRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, BinaryElementRole
, ExpressionElementRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from OrderByRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from AllowsLambdaRole
(via Cast
, ColumnElement
, OrderByRole
):
Class Variable | allows_lambda |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, OrderByRole
, ByOfRole
, ColumnListRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from ColumnsClauseRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from AllowsLambdaRole
(via Cast
, ColumnElement
, ColumnsClauseRole
):
Class Variable | allows_lambda |
Undocumented |
Inherited from UsesInspection
(via Cast
, ColumnElement
, ColumnsClauseRole
):
Class Variable | _post_inspect |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, ColumnsClauseRole
, ColumnListRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from LimitOffsetRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, LimitOffsetRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from DMLColumnRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, DMLColumnRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from DDLConstraintColumnRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, DDLConstraintColumnRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from DDLExpressionRole
(via Cast
, ColumnElement
):
Class Variable | _role_name |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, DDLExpressionRole
, StructuralRole
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from ColumnOperators
(via Cast
, ColumnElement
):
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 | __slots__ |
Undocumented |
Class Variable | timetuple |
Hack, allows datetime objects to be compared on the LHS. |
Inherited from Operators
(via Cast
, ColumnElement
, 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. |
Inherited from ClauseElement
(via Cast
, ColumnElement
):
Method | compare |
Compare this _expression.ClauseElement to the given _expression.ClauseElement . |
Method | compile |
Compile this SQL expression. |
Method | params |
Return a copy with _expression.bindparam elements replaced. |
Method | unique_params |
Return a copy with _expression.bindparam elements replaced. |
Method | __bool__ |
Undocumented |
Method | __getstate__ |
Undocumented |
Method | __invert__ |
Undocumented |
Method | __repr__ |
Undocumented |
Method | __str__ |
Undocumented |
Method | _clone |
Create a shallow copy of this ClauseElement. |
Method | _cloned_set |
Return the set consisting all cloned ancestors of this ClauseElement. |
Method | _compile_w_cache |
Undocumented |
Method | _compiler |
Return a compiler appropriate for this ClauseElement, given a Dialect. |
Method | _execute_on_connection |
Undocumented |
Method | _negate_in_binary |
a hook to allow the right side of a binary expression to respond to a negation of the binary expression. |
Method | _replace_params |
Undocumented |
Method | _set_propagate_attrs |
Undocumented |
Method | _ungroup |
Return this _expression.ClauseElement without any groupings. |
Method | _with_binary_element_type |
in the context of binary expression, convert the type of this object to the one given. |
Class Variable | _cache_key_traversal |
Undocumented |
Class Variable | _is_bind_parameter |
Undocumented |
Class Variable | _is_clause_list |
Undocumented |
Class Variable | _is_clone_of |
Undocumented |
Class Variable | _is_from_clause |
Undocumented |
Class Variable | _is_from_container |
Undocumented |
Class Variable | _is_immutable |
Undocumented |
Class Variable | _is_lambda_element |
Undocumented |
Class Variable | _is_returns_rows |
Undocumented |
Class Variable | _is_select_container |
Undocumented |
Class Variable | _is_select_statement |
Undocumented |
Class Variable | _is_singleton_constant |
Undocumented |
Class Variable | _is_text_clause |
Undocumented |
Class Variable | _is_textual |
Undocumented |
Class Variable | _order_by_label_element |
Undocumented |
Class Variable | bind |
Undocumented |
Class Variable | description |
Undocumented |
Class Variable | is_clause_element |
Undocumented |
Class Variable | is_selectable |
Undocumented |
Class Variable | stringify_dialect |
Undocumented |
Class Variable | supports_execution |
Undocumented |
Instance Variable | _propagate_attrs |
like annotations, however these propagate outwards liberally as SQL constructs are built, and are set up at construction time. |
Property | _constructor |
return the 'constructor' for this ClauseElement. |
Property | entity_namespace |
Undocumented |
Inherited from SQLRole
(via Cast
, ColumnElement
, ClauseElement
):
Class Variable | allows_lambda |
Undocumented |
Class Variable | uses_inspection |
Undocumented |
Inherited from SupportsWrappingAnnotations
(via Cast
, ColumnElement
, ClauseElement
):
Method | _annotate |
return a copy of this ClauseElement with annotations updated by the given dictionary. |
Method | _deannotate |
return a copy of this _expression.ClauseElement with annotations removed. |
Method | _with_annotations |
return a copy of this ClauseElement with annotations replaced by the given dictionary. |
Inherited from SupportsAnnotations
(via Cast
, ColumnElement
, ClauseElement
, SupportsWrappingAnnotations
):
Property | _annotations_cache_key |
Undocumented |
Inherited from MemoizedHasCacheKey
(via Cast
, ColumnElement
, ClauseElement
):
Method | _generate_cache_key |
return a cache key. |
Inherited from HasCacheKey
(via Cast
, ColumnElement
, ClauseElement
, MemoizedHasCacheKey
):
Class Variable | inherit_cache |
Indicate if this .HasCacheKey instance should make use of the cache key generation scheme used by its immediate superclass. |
Class Method | _generate_cache_attrs |
generate cache key dispatcher for a new class. |
Class Method | _generate_cache_key_for_object |
Undocumented |
Method | _gen_cache_key |
return an optional cache key. |
Class Variable | __slots__ |
Undocumented |
Class Variable | _hierarchy_supports_caching |
private attribute which may be set to False to prevent the inherit_cache warning from being emitted for a hierarchy of subclasses. |
Class Variable | _is_has_cache_key |
Undocumented |
Inherited from HasCopyInternals
(via Cast
, ColumnElement
, ClauseElement
):
Method | _copy_internals |
Reassign internal elements to be clones of themselves. |
Inherited from Traversible
(via Cast
, ColumnElement
, ClauseElement
):
Method | get_children |
Return immediate child .visitors.Traversible elements of this .visitors.Traversible . |
Method | __class_getitem__ |
Undocumented |
sqlalchemy.sql.elements.Cast.__init__
Produce a CAST expression.
.cast
returns an instance of .Cast
.
E.g.:
from sqlalchemy import cast, Numeric stmt = select(cast(product_table.c.unit_price, Numeric(10, 4)))
The above statement will produce SQL resembling:
SELECT CAST(unit_price AS NUMERIC(10, 4)) FROM product
The .cast
function performs two distinct functions when
used. The first is that it renders the CAST expression within
the resulting SQL string. The second is that it associates the given
type (e.g. .TypeEngine
class or instance) with the column
expression on the Python side, which means the expression will take
on the expression operator behavior associated with that type,
as well as the bound-value handling and result-row-handling behavior
of the type.
.cast
now applies the given type
to the expression such that it takes effect on the bound-value,
e.g. the Python-to-database direction, in addition to the
result handling, e.g. database-to-Python, direction.An alternative to .cast
is the .type_coerce
function.
This function performs the second task of associating an expression
with a specific type, but does not render the CAST expression
in SQL.
See Also
.type_coerce
- an alternative to CAST that coerces the type
on the Python side only, which is often sufficient to generate the
correct SQL and data coercion.
Parameters | |
expression | A SQL expression, such as a
_expression.ColumnElement
expression or a Python string which will be coerced into a bound
literal value. |
type_ | A .TypeEngine class or instance indicating
the type to which the CAST should apply. |