I want to filter the nested field with is_active column as True in Marshmallow 3 Consider following scenario I have 3 tables

users (id, name)
organizations (id, name)
organization_user(id, organization_id, user_id, is_active)

Now I'm trying to print all the organization with its members who are active. (There are some active and inactive members)

I have following schema

class OrganizationSchema(ma.ModelSchema):members_list = fields.Nested(OrgnizationUserSchema, many=True, exclude=('checklist', ))class OrgnizationUserSchema(ma.ModelSchema):user_list = fields.Nested(UserSchema)

Now in my action following is the code

organization_schema = OrganizationSchema(many=True)
#Query for list of organization
organization_list = Organization.query.all()
organization_schema.dump(organization_list)

Following is Output

[{'id': 1,'name': 'abc','members_list': [{'id':1, 'organization_id': 1, 'user_id':1, 'is_active':True},{'id':1, 'organization_id': 1, 'user_id':2, 'is_active':False}]}
]

I want output with member who has 'is_active':True as follows

[{'id': 1,'name': 'abc','members_list': [{'id':1, 'organization_id': 1, 'user_id':1, 'is_active':True}]}
]

Marshmallow provides a decorator @post_dump. Problem here is Query brings all data and then we filter it with decorator @post_dump. But the flow should be like, while querying there should be some way to filter the data and not post query filtering.

I went the other way. I have cloths, designs and remainders. For each fabric I need to get all the designs, and for each design will get the remainders for the specified city.

class ClothSchema(Schema):id = fields.Integer(dump_only=True)name = fields.String(validate=not_blank)type = fields.Nested(ClothTypeSchema)designs = fields.Nested(DesignSchema, many=True)class DesignSchema(Schema):id = fields.Integer(dump_only=True)name = fields.String(validate=not_blank)remainders = fields.Nested(RemainderSchema, many=True)class RemainderSchema(Schema):id = fields.Integer(dump_only=True)value = fields.String()city = fields.String()

I get the data I need in the controller so that they are not requested on the go.

    db.session.query(Cloth).join(Cloth.designs).join(Design.remainders).filter(Remainder.city == city).options(contains_eager("designs").contains_eager("remainders"))

As a result, I get all the cloths and all the designs for which the remainders are given. If no design remainders are indicated, it will not be displayed.

{"attributes": {"designs": {"data": [{"attributes": {"name": "Amely 10 ", "remainders": {"data": [{"attributes": {"city": "CityEnum.MOSCOW", "value": "333"}, "id": 9318, "type": "remainder"}]}}, "id": 365, "type": "design"} ], "links": {"self": "/designs"}}, "name": "Amely", "rapport": null, "type": {} }, "id": 22, "type": "cloth"
}