Edit - roles.py

Edit: roles.py

# sql/roles.py
# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
from __future__ import annotations

from typing import Any
from typing import Generic
from typing import Optional
from typing import TYPE_CHECKING
from typing import TypeVar

from .. import util
from ..util.typing import Literal

if TYPE_CHECKING:
    from ._typing import _PropagateAttrsType
    from .elements import Label
    from .selectable import _SelectIterable
    from .selectable import FromClause
    from .selectable import Subquery

_T = TypeVar("_T", bound=Any)
_T_co = TypeVar("_T_co", bound=Any, covariant=True)

class SQLRole:
    """Define a "role" within a SQL statement structure.

Classes within SQL Core participate within SQLRole hierarchies in order
    to more accurately indicate where they may be used within SQL statements
    of all types.

.. versionadded:: 1.4

"""

__slots__ = ()
    allows_lambda = False
    uses_inspection = False

class UsesInspection:
    __slots__ = ()
    _post_inspect: Literal[None] = None
    uses_inspection = True

class AllowsLambdaRole:
    __slots__ = ()
    allows_lambda = True

class HasCacheKeyRole(SQLRole):
    __slots__ = ()
    _role_name = "Cacheable Core or ORM object"

class ExecutableOptionRole(SQLRole):
    __slots__ = ()
    _role_name = "ExecutionOption Core or ORM object"

class LiteralValueRole(SQLRole):
    __slots__ = ()
    _role_name = "Literal Python value"

class ColumnArgumentRole(SQLRole):
    __slots__ = ()
    _role_name = "Column expression"

class ColumnArgumentOrKeyRole(ColumnArgumentRole):
    __slots__ = ()
    _role_name = "Column expression or string key"

class StrAsPlainColumnRole(ColumnArgumentRole):
    __slots__ = ()
    _role_name = "Column expression or string key"

class ColumnListRole(SQLRole):
    """Elements suitable for forming comma separated lists of expressions."""

__slots__ = ()

class StringRole(SQLRole):
    """mixin indicating a role that results in strings"""

__slots__ = ()

class TruncatedLabelRole(StringRole, SQLRole):
    __slots__ = ()
    _role_name = "String SQL identifier"

class ColumnsClauseRole(AllowsLambdaRole, UsesInspection, ColumnListRole):
    __slots__ = ()
    _role_name = (
        "Column expression, FROM clause, or other columns clause element"
    )

@property
    def _select_iterable(self) -> _SelectIterable:
        raise NotImplementedError()

class TypedColumnsClauseRole(Generic[_T_co], SQLRole):
    """element-typed form of ColumnsClauseRole"""

__slots__ = ()

class LimitOffsetRole(SQLRole):
    __slots__ = ()
    _role_name = "LIMIT / OFFSET expression"

class ByOfRole(ColumnListRole):
    __slots__ = ()
    _role_name = "GROUP BY / OF / etc. expression"

class GroupByRole(AllowsLambdaRole, UsesInspection, ByOfRole):
    __slots__ = ()
    # note there's a special case right now where you can pass a whole
    # ORM entity to group_by() and it splits out.   we may not want to keep
    # this around

_role_name = "GROUP BY expression"

class OrderByRole(AllowsLambdaRole, ByOfRole):
    __slots__ = ()
    _role_name = "ORDER BY expression"

class StructuralRole(SQLRole):
    __slots__ = ()

class StatementOptionRole(StructuralRole):
    __slots__ = ()
    _role_name = "statement sub-expression element"

class OnClauseRole(AllowsLambdaRole, StructuralRole):
    __slots__ = ()
    _role_name = (
        "ON clause, typically a SQL expression or "
        "ORM relationship attribute"
    )

class WhereHavingRole(OnClauseRole):
    __slots__ = ()
    _role_name = "SQL expression for WHERE/HAVING role"

class ExpressionElementRole(TypedColumnsClauseRole[_T_co]):
    # note when using generics for ExpressionElementRole,
    # the generic type needs to be in
    # sqlalchemy.sql.coercions._impl_lookup mapping also.
    # these are set up for basic types like int, bool, str, float
    # right now

__slots__ = ()
    _role_name = "SQL expression element"

def label(self, name: Optional[str]) -> Label[_T]:
        raise NotImplementedError()

class ConstExprRole(ExpressionElementRole[_T]):
    __slots__ = ()
    _role_name = "Constant True/False/None expression"

class LabeledColumnExprRole(ExpressionElementRole[_T]):
    __slots__ = ()

class BinaryElementRole(ExpressionElementRole[_T]):
    __slots__ = ()
    _role_name = "SQL expression element or literal value"

class InElementRole(SQLRole):
    __slots__ = ()
    _role_name = (
        "IN expression list, SELECT construct, or bound parameter object"
    )

class JoinTargetRole(AllowsLambdaRole, UsesInspection, StructuralRole):
    __slots__ = ()
    _role_name = (
        "Join target, typically a FROM expression, or ORM "
        "relationship attribute"
    )

class FromClauseRole(ColumnsClauseRole, JoinTargetRole):
    __slots__ = ()
    _role_name = "FROM expression, such as a Table or alias() object"

_is_subquery = False

named_with_column: bool

class StrictFromClauseRole(FromClauseRole):
    __slots__ = ()
    # does not allow text() or select() objects

class AnonymizedFromClauseRole(StrictFromClauseRole):
    __slots__ = ()

if TYPE_CHECKING:

def _anonymous_fromclause(
            self, *, name: Optional[str] = None, flat: bool = False
        ) -> FromClause: ...

class ReturnsRowsRole(SQLRole):
    __slots__ = ()
    _role_name = (
        "Row returning expression such as a SELECT, a FROM clause, or an "
        "INSERT/UPDATE/DELETE with RETURNING"
    )

class StatementRole(SQLRole):
    __slots__ = ()
    _role_name = "Executable SQL or text() construct"

if TYPE_CHECKING:

@util.memoized_property
        def _propagate_attrs(self) -> _PropagateAttrsType: ...

else:
        _propagate_attrs = util.EMPTY_DICT

class SelectStatementRole(StatementRole, ReturnsRowsRole):
    __slots__ = ()
    _role_name = "SELECT construct or equivalent text() construct"

def subquery(self) -> Subquery:
        raise NotImplementedError(
            "All SelectStatementRole objects should implement a "
            ".subquery() method."
        )

class HasCTERole(ReturnsRowsRole):
    __slots__ = ()

class IsCTERole(SQLRole):
    __slots__ = ()
    _role_name = "CTE object"

class CompoundElementRole(AllowsLambdaRole, SQLRole):
    """SELECT statements inside a CompoundSelect, e.g. UNION, EXTRACT, etc."""

__slots__ = ()
    _role_name = (
        "SELECT construct for inclusion in a UNION or other set construct"
    )

# TODO: are we using this?
class DMLRole(StatementRole):
    __slots__ = ()

class DMLTableRole(FromClauseRole):
    __slots__ = ()
    _role_name = "subject table for an INSERT, UPDATE or DELETE"

class DMLColumnRole(SQLRole):
    __slots__ = ()
    _role_name = "SET/VALUES column expression or string key"

class DMLSelectRole(SQLRole):
    """A SELECT statement embedded in DML, typically INSERT from SELECT"""

__slots__ = ()
    _role_name = "SELECT statement or equivalent textual object"

class DDLRole(StatementRole):
    __slots__ = ()

class DDLExpressionRole(StructuralRole):
    __slots__ = ()
    _role_name = "SQL expression element for DDL constraint"

class DDLConstraintColumnRole(SQLRole):
    __slots__ = ()
    _role_name = "String column name or column expression for DDL constraint"

class DDLReferredColumnRole(DDLConstraintColumnRole):
    __slots__ = ()
    _role_name = (
        "String column name or Column object for DDL foreign key constraint"
    )

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