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Tag: django

SQL double many-to-many relations with only two tables

Having two tables, one of them is called Tasks and the other one Relations where every task in Tasks might have 0-to-many predecessors and similarly, 0-to-many successors that relations among tasks are stored in the Relations-table. So, if Task_1 is predecessor of Task_2 and Task_2 is predecessor of Task_3 then I would like to store the following records in the

How to compose Django Model Filter for relation existence?

There is a many-to-many relationship between A and B. There are 3 tables to represent that relationship. TableA, TableB, TableAB Now I have another table TableC where it has a foreign key to TableA, and I want to filter objects from TableC where it has a relationship with TableB. The following is high-level code to give you the idea how

django ‘dict’ object has no attribute ‘job_id’

I’ve got this code: Even though value() is defined, I get the error ‘dict’ object has no attribute ‘job_id’ I guess the error will also be for pass_count, skip_count and fail_count What am I supposed to do here? Answer Your query does not return a queryset with object instances, so you cannot refer to fields with a “.” It is

Transforming SQL Query to Django Expression

Assuming I have the following Django models and the according SQL-Tables with some data. I have simplified the models so that it is clearer. UserAnswer: id answer partquestion_id 1 667 1 PartQuestion: id question_id part_id 1 1 1 Solution: id content question_id 1 667 1 2 85 2 I want to get all User answers where the answer is equal

Extract JSON content in Metabase SQL query

Using: Django==2.2.24, Python=3.6, PostgreSQL is underlying DB Working with Django ORM, I can easily make all sort of queries, but I started using Metabase, and my SQL might be a bit rusty. The problem: I am trying to get a count of the items in a list, under a key in a dictionary, stored as a JSONField: Example of the

Django ORM Left Join onto same table

I have a custom permissions system in a django project that can link any user to any specific model instance to grant permission on that object. It is more complex than this, but boiled down: I want to query for all permissions for any user, that are linked to the same content_object(s) that a particular user has been granted permission(s)