mirror of
https://github.com/sqlalchemy/sqlalchemy.git
synced 2026-05-30 12:34:52 -04:00
Mike Bayer
d6ce68727f
to rely upon server generated version identifiers, using triggers or other database-provided versioning features, by passing the value ``False``. The ORM will use RETURNING when available to immediately load the new version identifier, else it will emit a second SELECT. [ticket:2793] - The ``eager_defaults`` flag of :class:`.Mapper` will now allow the newly generated default values to be fetched using an inline RETURNING clause, rather than a second SELECT statement, for backends that support RETURNING. - Added a new variant to :meth:`.ValuesBase.returning` called :meth:`.ValuesBase.return_defaults`; this allows arbitrary columns to be added to the RETURNING clause of the statement without interfering with the compilers usual "implicit returning" feature, which is used to efficiently fetch newly generated primary key values. For supporting backends, a dictionary of all fetched values is present at :attr:`.ResultProxy.returned_defaults`. - add a glossary entry for RETURNING - add documentation for version id generation, [ticket:867]
127 lines
5.3 KiB
Python
127 lines
5.3 KiB
Python
# sql/expression.py
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# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""Defines the public namespace for SQL expression constructs.
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Prior to version 0.9, this module contained all of "elements", "dml",
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"default_comparator" and "selectable". The module was broken up
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and most "factory" functions were moved to be grouped with their associated
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class.
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"""
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__all__ = [
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'Alias', 'ClauseElement', 'ColumnCollection', 'ColumnElement',
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'CompoundSelect', 'Delete', 'FromClause', 'Insert', 'Join', 'Select',
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'Selectable', 'TableClause', 'Update', 'alias', 'and_', 'asc', 'between',
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'bindparam', 'case', 'cast', 'column', 'delete', 'desc', 'distinct',
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'except_', 'except_all', 'exists', 'extract', 'func', 'modifier',
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'collate', 'insert', 'intersect', 'intersect_all', 'join', 'label',
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'literal', 'literal_column', 'not_', 'null', 'nullsfirst', 'nullslast',
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'or_', 'outparam', 'outerjoin', 'over', 'select', 'subquery',
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'table', 'text',
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'tuple_', 'type_coerce', 'union', 'union_all', 'update']
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from .visitors import Visitable
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from .functions import func, modifier, FunctionElement
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from ..util.langhelpers import public_factory
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from .elements import ClauseElement, ColumnElement,\
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BindParameter, UnaryExpression, BooleanClauseList, \
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Label, Cast, Case, ColumnClause, TextClause, Over, Null, \
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True_, False_, BinaryExpression, Tuple, TypeClause, Extract, \
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Grouping, and_, or_, not_, \
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collate, literal_column, between,\
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literal, outparam, type_coerce, ClauseList
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from .elements import SavepointClause, RollbackToSavepointClause, \
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ReleaseSavepointClause
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from .base import ColumnCollection, Generative, Executable, \
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PARSE_AUTOCOMMIT
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from .selectable import Alias, Join, Select, Selectable, TableClause, \
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CompoundSelect, FromClause, FromGrouping, SelectBase, \
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alias, \
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subquery, HasPrefixes, Exists, ScalarSelect
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from .dml import Insert, Update, Delete, UpdateBase, ValuesBase
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# factory functions - these pull class-bound constructors and classmethods
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# from SQL elements and selectables into public functions. This allows
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# the functions to be available in the sqlalchemy.sql.* namespace and
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# to be auto-cross-documenting from the function to the class itself.
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bindparam = public_factory(BindParameter, ".expression.bindparam")
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select = public_factory(Select, ".expression.select")
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text = public_factory(TextClause, ".expression.tet")
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table = public_factory(TableClause, ".expression.table")
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column = public_factory(ColumnClause, ".expression.column")
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over = public_factory(Over, ".expression.over")
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label = public_factory(Label, ".expression.label")
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case = public_factory(Case, ".expression.case")
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cast = public_factory(Cast, ".expression.cast")
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extract = public_factory(Extract, ".expression.extract")
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tuple_ = public_factory(Tuple, ".expression.tuple_")
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except_ = public_factory(CompoundSelect._create_except, ".expression.except_")
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except_all = public_factory(CompoundSelect._create_except_all, ".expression.except_all")
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intersect = public_factory(CompoundSelect._create_intersect, ".expression.intersect")
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intersect_all = public_factory(CompoundSelect._create_intersect_all, ".expression.intersect_all")
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union = public_factory(CompoundSelect._create_union, ".expression.union")
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union_all = public_factory(CompoundSelect._create_union_all, ".expression.union_all")
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exists = public_factory(Exists, ".expression.exists")
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nullsfirst = public_factory(UnaryExpression._create_nullsfirst, ".expression.nullsfirst")
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nullslast = public_factory(UnaryExpression._create_nullslast, ".expression.nullslast")
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asc = public_factory(UnaryExpression._create_asc, ".expression.asc")
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desc = public_factory(UnaryExpression._create_desc, ".expression.desc")
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distinct = public_factory(UnaryExpression._create_distinct, ".expression.distinct")
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true = public_factory(True_, ".expression.true")
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false = public_factory(False_, ".expression.false")
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null = public_factory(Null, ".expression.null")
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join = public_factory(Join._create_join, ".expression.join")
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outerjoin = public_factory(Join._create_outerjoin, ".expression.outerjoin")
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insert = public_factory(Insert, ".expression.insert")
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update = public_factory(Update, ".expression.update")
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delete = public_factory(Delete, ".expression.delete")
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# internal functions still being called from tests and the ORM,
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# these might be better off in some other namespace
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from .base import _from_objects
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from .elements import _literal_as_text, _clause_element_as_expr,\
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_is_column, _labeled, _only_column_elements, _string_or_unprintable, \
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_truncated_label, _clone, _cloned_difference, _cloned_intersection,\
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_column_as_key, _literal_as_binds, _select_iterables, \
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_corresponding_column_or_error
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from .selectable import _interpret_as_from
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# old names for compatibility
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_Executable = Executable
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_BindParamClause = BindParameter
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_Label = Label
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_SelectBase = SelectBase
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_BinaryExpression = BinaryExpression
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_Cast = Cast
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_Null = Null
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_False = False_
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_True = True_
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_TextClause = TextClause
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_UnaryExpression = UnaryExpression
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_Case = Case
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_Tuple = Tuple
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_Over = Over
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_Generative = Generative
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_TypeClause = TypeClause
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_Extract = Extract
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_Exists = Exists
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_Grouping = Grouping
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_FromGrouping = FromGrouping
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_ScalarSelect = ScalarSelect
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