django-queryset

问题 I'm trying to add some extra attributes to the elements of a QuerySet so I can use the extra information in templates, instead of hitting the database multiple times. Let me illustrate by example, assuming we have Books with ForeignKeys to Authors. >>> books = Book.objects.filter(author__id=1) >>> for book in books: ... book.price = 2 # "price" is not defined in the Book model >>> # Check I can get back the extra information (this works in templates too): >>> books[0].price 2 >>> # but it's

问题 I have a value and want to get all instances having the value in one or more column. And to make this a bit more complex, the field list is dynamic. So, what I have is: ['field1', 'field2', 'field3', ...] What I need is: Q(field1='value') | Q(field2='value') | Q(field3='value') | ... How can I get this? 回答1: Use ** dictionary-to-kw-args expansion: q = Q() for field in fields: q = q | Q(**{field: "value"}) (as Q() yield a Q which "does nothing", as far as I can tell) 来源： https://stackoverflow

问题 In this question was solved problem for reverse LIKE operation in SQL, for example if field name is "Peter Johnson", we could find it by such query: select name from user where "Mr. Peter Johnson" like CONCAT('%', name, '%') Is there any way to do such thing in Django Q object (I'm building a big query, so using raw SQL query will not be rational)? 回答1: While extras do provide an expanded complex functionality for edge cases, extras should be treated as last resort and likely going to be

问题 I've got a model similar to this: class Person(models.Model): name = models.CharField(max_length=40) birthday = DateTimeField() # their next birthday I would like to get a list of the total birthdays for each day for the next 30 days. So for example, the list would look like this: [[9, 0], [10, 3], [11, 1], [12, 1], [13, 5], ... #30 entries in list Each list entry in the list is a date number followed by the number of birthdays on that day. So for example on the 9th of May there are 0

问题 I am using the filter icontains to search for words but I only want it to match whole words. e.g. if I searched for liver I wouldn't want it returning delivery. my query looks like this MyModel.objects.filter(title__icontains=search_word) I have seen the filter __search but this does not bring back results with 3 characters or less and the site I am building contains a lot of these which could be searched for, e.g. 'bbc' I do not have access to the db but if anyone knows how I can disable

问题 I have 2 models in my django code: class ModelA(models.Model): name = models.CharField(max_length=255) description = models.CharField(max_length=255) created_by = models.ForeignKey(User) class ModelB(models.Model): category = models.CharField(max_length=255) modela_link = models.ForeignKey(ModelA, 'modelb_link') functions = models.CharField(max_length=255) created_by = models.ForeignKey(User) Say ModelA has 100 records, all of which may or may not have links to ModelB Now say I want to get a

问题 Is there a way to do a query and exclude a list of things, instead of calling exclude multiple times? 回答1: Based on your reply to Ned, it sounds like you just want to exclude a list of tags. So you could just use the in filter: names_to_exclude = [o.name for o in objects_to_exclude] Foo.objects.exclude(name__in=names_to_exclude) Does that do what you want? 回答2: What's wrong with calling exclude multiple times? Queries are lazy, nothing happens until you try to pull data from it, so there's no

问题 Is there a way to do a query and exclude a list of things, instead of calling exclude multiple times? 回答1: Based on your reply to Ned, it sounds like you just want to exclude a list of tags. So you could just use the in filter: names_to_exclude = [o.name for o in objects_to_exclude] Foo.objects.exclude(name__in=names_to_exclude) Does that do what you want? 回答2: What's wrong with calling exclude multiple times? Queries are lazy, nothing happens until you try to pull data from it, so there's no

问题 Is there a way to do a query and exclude a list of things, instead of calling exclude multiple times? 回答1: Based on your reply to Ned, it sounds like you just want to exclude a list of tags. So you could just use the in filter: names_to_exclude = [o.name for o in objects_to_exclude] Foo.objects.exclude(name__in=names_to_exclude) Does that do what you want? 回答2: What's wrong with calling exclude multiple times? Queries are lazy, nothing happens until you try to pull data from it, so there's no

问题 I have a MySQL database unfortunately used with Django 1.4.1. Distinct function is only working for POSTGRESQL if i get it right. I have to make a distinct query consist of multiple values while only distinct one, Like; This one works for POSTGRE but not with MYSQL, I get the following error; DISTINCT ON fields is not supported by this database backend staff = Staff.objects.order_by('person__full_name').distinct('person__full_name') Then I tried staff = Staff.objects.values('person__full_name