diff options
Diffstat (limited to 'lib/sqlalchemy/sql/selectable.py')
| -rw-r--r-- | lib/sqlalchemy/sql/selectable.py | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index 2e8f41cc8..5fc83815d 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -2168,6 +2168,13 @@ class TableClause(roles.DMLTableRole, Immutable, FromClause): return self.name.encode("ascii", "backslashreplace") def append_column(self, c): + existing = c.table + if existing is not None and existing is not self: + raise exc.ArgumentError( + "column object '%s' already assigned to table '%s'" + % (c.key, existing) + ) + self._columns.add(c) c.table = self |