Mutations - batch creation of objects

Question

I want to use graphene to create many people in one go. The document only mention the way to create one person like this:

class CreatePerson(graphene.Mutation):
class Input:
    name = graphene.String()
    age = graphene.Int()

ok = graphene.Boolean()
person = graphene.Field(lambda: Person)

@staticmethod
def mutate(root, args, context, info):
    person = Person(name=args.get('name'), age=args.get('age'), mobile=args.get('mobile'))
    ok = True
    return CreatePerson(person=person, ok=ok)

are there any ways to get it done?

FYI you can post your solution as an answer and accept it so people coming after you can easily see the final solution. — Jan Hančič, May 20 '17 at 10:08

marktani · Answer 1 · 2018-08-30T13:00:01.587

9

Instead of using a mutation that creates a list of objects, you can also call a mutation that creates one objects multiple times in one GraphQL request. This is accomplished using GraphQL Aliases:

mutation {
  c001: createPerson(
    name: "Donald Duck"
    age: 42
  ) {
    id
  }

  c002: createPerson(
    name: "Daisy Duck"
    age: 43
  ) {
    id
  }

  c003: createPerson(
    name: "Mickey Mouse"
    age: 44
  ) {
    id
  }
}

edited Aug 30 '18 at 13:00

answered May 20 '17 at 12:38

marktani

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1

the link to the FAQ is dead. – lbrahim Feb 13 '18 at 12:11
which one is better, the batch of list or batch of alias? – A l w a y s S u n n y Aug 12 '21 at 06:04

Quy Tang · Accepted Answer · 2018-01-13T05:11:25.403

5

I can figure out a solution base on the answer of Jan Hančič

There is a type called graphene.InputObjectType to use in this case

The solution can be

class PersonInput(InputObjectType):
    name = graphene.String()
    age = graphene.Int()

class CreatePeople(graphene.Mutation):
    class Input:
       people = graphene.List(PersonInput)

    people = graphene.List(lambda: Person)

    @staticmethod
    def mutate(root, args, context, info):
        people = [Person.objects.create(name=person.name, age=person.age) for person in args.get('people')]
        return CreatePeople(people=people)

edited Jan 13 '18 at 05:11

answered Jan 13 '18 at 04:43

Quy Tang

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I created a mutation this way but I can't find a way how to write a graphql query for this. How do you do that? – Karina Klinkevičiūtė Oct 26 '21 at 14:23
1

@KarinaKlinkevičiūtė you can find the answer here - https://docs.graphene-python.org/projects/django/en/latest/queries/ – Quy Tang Oct 27 '21 at 04:26

score 4 · Answer 3 · answered May 19 '17 at 13:17

4

Make your mutation input a list and return a list of created people. Something like this:

class CreatePerson(graphene.Mutation):
    class Input:
        name = graphene.List(graphene.String)

    ok = graphene.Boolean()
    people = graphene.List(Person)

    @staticmethod
    def mutate(root, args, context, info):
        people = [Person(name=name) for name in args.get('name)]
        ok = True
        return CreatePerson(people=people, ok=ok)

answered May 19 '17 at 13:17

Jan Hančič

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great! but how can I deal with more than one field. E.g. name, address and age for the person? – Quy Tang May 19 '17 at 14:02
2

You can have complex input types, see the docs: http://docs.graphene-python.org/en/latest/types/mutations/ – Jan Hančič May 19 '17 at 14:13
Hi Jan, I use the InputObject and it worked but the data was not saved to the db. Would you mind helping on this. Thank you very much! – Quy Tang May 20 '17 at 03:14

score 4 · Answer 4 · edited Jan 24 '19 at 20:00

Receive a list of input, create all instances and return them all

The model node/type should be like-

class UserType(DjangoObjectType):

    class Meta:
        model = User
        interfaces = (CustomGrapheneNode, )
        filter_fields = {}
        only_fields = (
            'name',
            'email'
        )

Define Input fields

class UserInput(graphene.InputObjectType):
    name = graphene.String(required=True)
    password = graphene.String(required=True)

Mutation class

class CreateUser(graphene.Mutation):
    users = graphene.List(UserType)

    class Input:
        data = graphene.List(UserInput)

    Output = graphene.List(UserType)

    def mutate(self, info, data):
        users = []
        for item in data:
            user = User.objects.create(name=data['name'], 
                                       password=data['password'])
            users.append(user)
        return users

make this mutation callable by main schema

class Mutation():
    create_user = CreateUser.Field()

the Mutation Query view will be as -

mutation{
    createUser(data:[{name:"john", password:"1234"},
                     {name:"john", password:"1234"}]) {
        user{
            name
        }
    }    
}

good solution. Just to add you could use the bulk_create() method there in the mutate() function as described in the docs: https://docs.djangoproject.com/en/3.2/ref/models/querysets/ — Rafael Santos, Jul 16 '21 at 15:16
in case someone else tries this answer and you run into error, in the mutate function just change for item in data: user = User.objects.create(name=data['name'], password=data['password']) to instead: for item in data: user = User.objects.create(name=item['name'], password=item['password']) — Rafael Santos, Jul 16 '21 at 15:48

Mutations - batch creation of objects

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