Class ExcludeConstraint

lib/sqlalchemy/dialects/postgresql/ext.py:141–327

A table-level EXCLUDE constraint. Defines an EXCLUDE constraint as described in the `PostgreSQL documentation`__. __ https://www.postgresql.org/docs/current/static/sql-createtable.html#SQL-CREATETABLE-EXCLUDE

class ExcludeConstraint(ColumnCollectionConstraint):
    """A table-level EXCLUDE constraint.

    Defines an EXCLUDE constraint as described in the `PostgreSQL
    documentation`__.

    __ https://www.postgresql.org/docs/current/static/sql-createtable.html#SQL-CREATETABLE-EXCLUDE

    """  # noqa

    __visit_name__ = "exclude_constraint"

    where = None
    inherit_cache = False

    create_drop_stringify_dialect = "postgresql"

    @elements._document_text_coercion(
        "where",
        ":class:`.ExcludeConstraint`",
        ":paramref:`.ExcludeConstraint.where`",
    )
    def __init__(
        self, *elements: Tuple[_DDLColumnArgument, str], **kw: Any
    ) -> None:
        r"""
        Create an :class:`.ExcludeConstraint` object.

        E.g.::

            const = ExcludeConstraint(
                (Column("period"), "&&"),
                (Column("group"), "="),
                where=(Column("group") != "some group"),
                ops={"group": "my_operator_class"},
            )

        The constraint is normally embedded into the :class:`_schema.Table`
        construct
        directly, or added later using :meth:`.append_constraint`::

            some_table = Table(
                "some_table",
                metadata,
                Column("id", Integer, primary_key=True),
                Column("period", TSRANGE()),
                Column("group", String),
            )

            some_table.append_constraint(
                ExcludeConstraint(
                    (some_table.c.period, "&&"),
                    (some_table.c.group, "="),
                    where=some_table.c.group != "some group",
                    name="some_table_excl_const",
                    ops={"group": "my_operator_class"},
                )
            )