| """ |
| Useful auxilliary data structures for query construction. Not useful outside |
| the SQL domain. |
| """ |
| |
| class EmptyResultSet(Exception): |
| pass |
| |
| class FullResultSet(Exception): |
| pass |
| |
| class MultiJoin(Exception): |
| """ |
| Used by join construction code to indicate the point at which a |
| multi-valued join was attempted (if the caller wants to treat that |
| exceptionally). |
| """ |
| def __init__(self, level): |
| self.level = level |
| |
| class Empty(object): |
| pass |
| |
| class RawValue(object): |
| def __init__(self, value): |
| self.value = value |
| |
| class Date(object): |
| """ |
| Add a date selection column. |
| """ |
| def __init__(self, col, lookup_type): |
| self.col = col |
| self.lookup_type = lookup_type |
| |
| def relabel_aliases(self, change_map): |
| c = self.col |
| if isinstance(c, (list, tuple)): |
| self.col = (change_map.get(c[0], c[0]), c[1]) |
| |
| def as_sql(self, qn, connection): |
| if isinstance(self.col, (list, tuple)): |
| col = '%s.%s' % tuple([qn(c) for c in self.col]) |
| else: |
| col = self.col |
| return connection.ops.date_trunc_sql(self.lookup_type, col) |
