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Edit File: roles.py
# sql/roles.py # Copyright (C) 2005-2024 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 .. import util class SQLRole(object): """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 """ allows_lambda = False uses_inspection = False class UsesInspection(object): _post_inspect = None uses_inspection = True class AllowsLambdaRole(object): allows_lambda = True class HasCacheKeyRole(SQLRole): _role_name = "Cacheable Core or ORM object" class ExecutableOptionRole(SQLRole): __slots__ = () _role_name = "ExecutionOption Core or ORM object" class LiteralValueRole(SQLRole): _role_name = "Literal Python value" class ColumnArgumentRole(SQLRole): _role_name = "Column expression" class ColumnArgumentOrKeyRole(ColumnArgumentRole): _role_name = "Column expression or string key" class StrAsPlainColumnRole(ColumnArgumentRole): _role_name = "Column expression or string key" class ColumnListRole(SQLRole): """Elements suitable for forming comma separated lists of expressions.""" class TruncatedLabelRole(SQLRole): _role_name = "String SQL identifier" class ColumnsClauseRole(AllowsLambdaRole, UsesInspection, ColumnListRole): _role_name = "Column expression or FROM clause" @property def _select_iterable(self): raise NotImplementedError() class LimitOffsetRole(SQLRole): _role_name = "LIMIT / OFFSET expression" class ByOfRole(ColumnListRole): _role_name = "GROUP BY / OF / etc. expression" class GroupByRole(AllowsLambdaRole, UsesInspection, ByOfRole): # 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): _role_name = "ORDER BY expression" class StructuralRole(SQLRole): pass class StatementOptionRole(StructuralRole): _role_name = "statement sub-expression element" class OnClauseRole(AllowsLambdaRole, StructuralRole): _role_name = "SQL expression for ON clause" class WhereHavingRole(OnClauseRole): _role_name = "SQL expression for WHERE/HAVING role" class ExpressionElementRole(SQLRole): _role_name = "SQL expression element" class ConstExprRole(ExpressionElementRole): _role_name = "Constant True/False/None expression" class LabeledColumnExprRole(ExpressionElementRole): pass class BinaryElementRole(ExpressionElementRole): _role_name = "SQL expression element or literal value" class InElementRole(SQLRole): _role_name = ( "IN expression list, SELECT construct, or bound parameter object" ) class JoinTargetRole(AllowsLambdaRole, UsesInspection, StructuralRole): _role_name = ( "Join target, typically a FROM expression, or ORM " "relationship attribute" ) class FromClauseRole(ColumnsClauseRole, JoinTargetRole): _role_name = "FROM expression, such as a Table or alias() object" _is_subquery = False @property def _hide_froms(self): raise NotImplementedError() class StrictFromClauseRole(FromClauseRole): # does not allow text() or select() objects @property def description(self): raise NotImplementedError() class AnonymizedFromClauseRole(StrictFromClauseRole): # calls .alias() as a post processor def _anonymous_fromclause(self, name=None, flat=False): raise NotImplementedError() class ReturnsRowsRole(SQLRole): _role_name = ( "Row returning expression such as a SELECT, a FROM clause, or an " "INSERT/UPDATE/DELETE with RETURNING" ) class StatementRole(SQLRole): _role_name = "Executable SQL or text() construct" _propagate_attrs = util.immutabledict() class SelectStatementRole(StatementRole, ReturnsRowsRole): _role_name = "SELECT construct or equivalent text() construct" def subquery(self): raise NotImplementedError( "All SelectStatementRole objects should implement a " ".subquery() method." ) class HasCTERole(ReturnsRowsRole): pass class IsCTERole(SQLRole): _role_name = "CTE object" class CompoundElementRole(AllowsLambdaRole, SQLRole): """SELECT statements inside a CompoundSelect, e.g. UNION, EXTRACT, etc.""" _role_name = ( "SELECT construct for inclusion in a UNION or other set construct" ) # TODO: are we using this? class DMLRole(StatementRole): pass class DMLTableRole(FromClauseRole): _role_name = "subject table for an INSERT, UPDATE or DELETE" class DMLColumnRole(SQLRole): _role_name = "SET/VALUES column expression or string key" class DMLSelectRole(SQLRole): """A SELECT statement embedded in DML, typically INSERT from SELECT""" _role_name = "SELECT statement or equivalent textual object" class DDLRole(StatementRole): pass class DDLExpressionRole(StructuralRole): _role_name = "SQL expression element for DDL constraint" class DDLConstraintColumnRole(SQLRole): _role_name = "String column name or column expression for DDL constraint" class DDLReferredColumnRole(DDLConstraintColumnRole): _role_name = ( "String column name or Column object for DDL foreign key constraint" )