Django Union Query

Question

I need to develop a UNION query in Django with 3 models namely WebQuery,WebReply and BusinessOwners and the output should be of the form below.

{
    \"(#convers         


        

Answer 1

How can I find the union of two Django querysets? provides an example of a union using the '|' operator. I'm not sure how different your models are. If there's common fields you could place those in a separate model and use model inheritance

Answer 2

I personally would say that if this is going to be a common query then I would recommend making a SQL View then querying that.

w3schools has a VERY simple overview of what a view is : http://www.w3schools.com/sql/sql_view.asp

In SQL, a view is a virtual table based on the result-set of an SQL statement.

This means you can write your required sql statement and create a view using this. Then create a django model which mirrors that view which you can then use to query.

So, you will create an SQL view:

CREATE VIEW view_name AS
    SELECT a, b, c
    FROM table_name
    WHERE condition

Then create a django model, which has a slight difference to a normal model:

class view_name(models.Model):
    class Meta:
        # https://docs.djangoproject.com/en/1.5/ref/models/options/#django.db.models.Options.managed
        managed = False

    a = models.CharField(max_length)
    ....

managed = false > https://docs.djangoproject.com/en/1.5/ref/models/options/#django.db.models.Options.managed

You can then query this using the normal django orm syntax

Or there is similar questions:

Previous stackoverflow question, union in django orm

How can I find the union of two Django querysets?