Classe « DDL »

Informations générales

Héritage

        builtins.object
            Visitable
                CompilerElement
        builtins.object
            Visitable
        builtins.object
            HasTraverseInternals
                ExternallyTraversible
        builtins.object
            HasTraverseInternals
                HasCopyInternals
        builtins.object
            HasMemoized
        builtins.object
            HasCacheKey
                MemoizedHasCacheKey
builtins.object
    Visitable
builtins.object
    HasTraverseInternals
        ExternallyTraversible
            SupportsAnnotations
                SupportsWrappingAnnotations
                    ClauseElement
                        BaseDDLElement
            builtins.object
                SQLRole
                    StatementRole
                        Executable
            builtins.object
                SQLRole
                    StatementRole
                        DDLRole
                            ExecutableDDLElement
                                DDL

Définition

class DDL(ExecutableDDLElement):

help(DDL)

A literal DDL statement.

Specifies literal SQL DDL to be executed by the database.  DDL objects
function as DDL event listeners, and can be subscribed to those events
listed in :class:`.DDLEvents`, using either :class:`_schema.Table` or
:class:`_schema.MetaData` objects as targets.
Basic templating support allows
a single DDL instance to handle repetitive tasks for multiple tables.

Examples::

  from sqlalchemy import event, DDL

  tbl = Table("users", metadata, Column("uid", Integer))
  event.listen(tbl, "before_create", DDL("DROP TRIGGER users_trigger"))

  spow = DDL("ALTER TABLE %(table)s SET secretpowers TRUE")
  event.listen(tbl, "after_create", spow.execute_if(dialect="somedb"))

  drop_spow = DDL("ALTER TABLE users SET secretpowers FALSE")
  connection.execute(drop_spow)

When operating on Table events, the following ``statement``
string substitutions are available:

.. sourcecode:: text

  %(table)s  - the Table name, with any required quoting applied
  %(schema)s - the schema name, with any required quoting applied
  %(fullname)s - the Table name including schema, quoted if needed

The DDL's "context", if any, will be combined with the standard
substitutions noted above.  Keys present in the context will override
the standard substitutions.

Constructeur(s)

Signature du constructeur	Description
__init__(self, statement, context=None)	Create a DDL statement. _{[extrait de __init__.__doc__]}

Liste des attributs statiques

Nom de l'attribut	Valeur
allows_lambda	False
description	<sqlalchemy.util.langhelpers._memoized_property object at 0x0000020D9F723AD0>
inherit_cache	None
is_clause_element	True
is_delete	False
is_dml	False
is_from_statement	False
is_insert	False
is_select	False
is_selectable	False
is_text	False
is_update	False
stringify_dialect	default
supports_execution	True
target	None
uses_inspection	False