Class MetaData

lib/sqlalchemy/sql/schema.py:5389–5959

A collection of :class:`_schema.Table` objects and their associated schema constructs. Holds a collection of :class:`_schema.Table` objects as well as an optional binding to an :class:`_engine.Engine` or :class:`_engine.Connection`. If bound, the :class:`_schema.Table` objects

class MetaData(HasSchemaAttr):
    """A collection of :class:`_schema.Table`
    objects and their associated schema
    constructs.

    Holds a collection of :class:`_schema.Table` objects as well as
    an optional binding to an :class:`_engine.Engine` or
    :class:`_engine.Connection`.  If bound, the :class:`_schema.Table` objects
    in the collection and their columns may participate in implicit SQL
    execution.

    The :class:`_schema.Table` objects themselves are stored in the
    :attr:`_schema.MetaData.tables` dictionary.

    :class:`_schema.MetaData` is a thread-safe object for read operations.
    Construction of new tables within a single :class:`_schema.MetaData`
    object,
    either explicitly or via reflection, may not be completely thread-safe.

    .. seealso::

        :ref:`metadata_describing` - Introduction to database metadata

    """

    __visit_name__ = "metadata"

    def __init__(
        self,
        schema: Optional[str] = None,
        quote_schema: Optional[bool] = None,
        naming_convention: Optional[_NamingSchemaParameter] = None,
        info: Optional[_InfoType] = None,
    ) -> None:
        """Create a new MetaData object.

        :param schema:
           The default schema to use for the :class:`_schema.Table`,
           :class:`.Sequence`, and potentially other objects associated with
           this :class:`_schema.MetaData`. Defaults to ``None``.

           .. seealso::

                :ref:`schema_metadata_schema_name` - details on how the
                :paramref:`_schema.MetaData.schema` parameter is used.

                :paramref:`_schema.Table.schema`

                :paramref:`.Sequence.schema`

        :param quote_schema:
            Sets the ``quote_schema`` flag for those :class:`_schema.Table`,
            :class:`.Sequence`, and other objects which make usage of the
            local ``schema`` name.

        :param info: Optional data dictionary which will be populated into the
            :attr:`.SchemaItem.info` attribute of this object.