Read multiple records as one in Django

Question

everyone, I am in the middle of a grouping of rows of a table Relationship with the same name as one. example- the table will look like

Parent_name .... Childern_name
==============
A Mittal ........ Children 1
-----------------
A Mittal ........ Children 2
-----------------
A Mittal ........ Children 3
-----------------
B Mittal .........children 1
-----------------
B Mittal .........children 2

Now I created an HTML where I want to see only

A Mittal 
B Mittal

For which I have to define in views -

parentnames= Relationship.objects.distinct(Parent_name)

But it's not working kindly help. Is there any other way also to do it?

Answer 1

You can obtain a QuerySet of Parent_names by using .values_list(…) [Django-doc]:

parentnames= Relationship.objects.values_list(
    'Parent_name', flat=True
).distinct()

That being said, by storing the names in the Relationship, you introduce data duplication. It makes it harder to update a name. For example, if A Mittal is renamed to C Mittal, it will require some querying to rename all Parent_names and Child_names where A Mittal is present. Therefore one often makes a dedicated model to store details about the object (like its name), and uses ForeignKeys. This is also more efficient, since by default a ForeignKey will add a database index on the corresponding column.