Method append_column

lib/sqlalchemy/sql/schema.py:1209–1248

Append a :class:`_schema.Column` to this :class:`_schema.Table`. The "key" of the newly added :class:`_schema.Column`, i.e. the value of its ``.key`` attribute, will then be available in the ``.c`` collection of this :class:`_schema.Table`, and the column definition

(
        self, column: ColumnClause[Any], replace_existing: bool = False
    )

        self._extra_dependencies.add(table)

    def append_column(
        self, column: ColumnClause[Any], replace_existing: bool = False
    ) -> None:
        """Append a :class:`_schema.Column` to this :class:`_schema.Table`.

        The "key" of the newly added :class:`_schema.Column`, i.e. the
        value of its ``.key`` attribute, will then be available
        in the ``.c`` collection of this :class:`_schema.Table`, and the
        column definition will be included in any CREATE TABLE, SELECT,
        UPDATE, etc. statements generated from this :class:`_schema.Table`
        construct.

        Note that this does **not** change the definition of the table
        as it exists within any underlying database, assuming that
        table has already been created in the database.   Relational
        databases support the addition of columns to existing tables
        using the SQL ALTER command, which would need to be
        emitted for an already-existing table that doesn't contain
        the newly added column.

        :param replace_existing: When ``True``, allows replacing existing
            columns. When ``False``, the default, an warning will be raised
            if a column with the same ``.key`` already exists. A future
            version of sqlalchemy will instead rise a warning.

            .. versionadded:: 1.4.0
        """

        try:
            column._set_parent_with_dispatch(
                self,
                allow_replacements=replace_existing,
                all_names={c.name: c for c in self.c},
            )
        except exc.DuplicateColumnError as de:
            raise exc.DuplicateColumnError(
                f"{de.args[0]} Specify replace_existing=True to "
                "Table.append_column() to replace an "
                "existing column."
            ) from de

    def append_constraint(self, constraint: Union[Index, Constraint]) -> None:
        """Append a :class:`_schema.Constraint` to this