app/django/db/models/query_utils.py
author Pawel Solyga <Pawel.Solyga@gmail.com>
Fri, 12 Sep 2008 16:33:04 +0000
changeset 135 a7ccde9d9eed
parent 54 03e267d67478
child 323 ff1a9aa48cfd
permissions -rw-r--r--
Fixed one typo in response_helpers which caused is_admin context variable not to work correctly. Created new checkLinkNameForId function that checks if link_name is correct when creating new user and modifying existing one. This is now used for validation instead of doesLinkNameBelongToId in UserForm clean_link_name function. The previous validation function didn't allow to create new users and modify linkname of existing ones. Additionally I created new doesLinkNameExist helper function.

"""
Various data structures used in query construction.

Factored out from django.db.models.query so that they can also be used by other
modules without getting into circular import difficulties.
"""

from copy import deepcopy

from django.utils import tree

class QueryWrapper(object):
    """
    A type that indicates the contents are an SQL fragment and the associate
    parameters. Can be used to pass opaque data to a where-clause, for example.
    """
    def __init__(self, sql, params):
        self.data = sql, params

class Q(tree.Node):
    """
    Encapsulates filters as objects that can then be combined logically (using
    & and |).
    """
    # Connection types
    AND = 'AND'
    OR = 'OR'
    default = AND

    def __init__(self, *args, **kwargs):
        super(Q, self).__init__(children=list(args) + kwargs.items())

    def _combine(self, other, conn):
        if not isinstance(other, Q):
            raise TypeError(other)
        obj = deepcopy(self)
        obj.add(other, conn)
        return obj

    def __or__(self, other):
        return self._combine(other, self.OR)

    def __and__(self, other):
        return self._combine(other, self.AND)

    def __invert__(self):
        obj = deepcopy(self)
        obj.negate()
        return obj