conditional_expressions.py 文件源码

def registrations_matching_complex_pattern():
    """
    Q objects generation can be also automated
    """
    predicate_list = [
        ('event__name__endswith', 'python'),
        ('member__community__name__contains', 'python')
    ]
    q_object_list = [Q(predicate) for predicate in predicate_list]
    pattern = reduce(OR, q_object_list)
    registration_number = Registration.objects.filter(pattern).count()
    print("{nbr} match the pattern 'python'".format(nbr=registration_number))


## When(), Case() expressions
##############################