Function _get_update_multitable_params

lib/sqlalchemy/sql/crud.py:1399–1498

(
    compiler,
    stmt,
    compile_state,
    stmt_parameter_tuples,
    check_columns,
    _col_bind_name,
    _getattr_col_key,
    values,
    kw,
)

def _get_update_multitable_params(
    compiler,
    stmt,
    compile_state,
    stmt_parameter_tuples,
    check_columns,
    _col_bind_name,
    _getattr_col_key,
    values,
    kw,
):
    normalized_params = {
        coercions.expect(roles.DMLColumnRole, c): param
        for c, param in stmt_parameter_tuples or ()
    }

    include_table = compile_state.include_table_with_column_exprs

    affected_tables = set()
    for t in compile_state._extra_froms:
        # extra gymnastics to support the probably-shouldnt-have-supported
        # case of "UPDATE table AS alias SET table.foo = bar", but it's
        # supported
        we_shouldnt_be_here_if_columns_found = (
            not include_table
            and not compile_state.dml_table.is_derived_from(t)
        )

        for c in t.c:
            if c in normalized_params:

                if we_shouldnt_be_here_if_columns_found:
                    raise exc.CompileError(
                        "Backend does not support additional tables "
                        "in the SET "
                        "clause; cannot include columns from table(s) "
                        f"'{t.description}' in "
                        "SET clause"
                    )

                affected_tables.add(t)

                check_columns[_getattr_col_key(c)] = c
                value = normalized_params[c]

                col_value = compiler.process(c, include_table=include_table)
                if coercions._is_literal(value):
                    value = _create_bind_param(
                        compiler,
                        c,
                        value,
                        required=value is REQUIRED,
                        name=_col_bind_name(c),
                        **kw,  # TODO: no test coverage for literal binds here
                    )
                    accumulated_bind_names: Iterable[str] = (c.key,)
                elif value._is_bind_parameter:
                    cbn = _col_bind_name(c)