Data:

Transaction table with region field (Oracle database-Only read access).
Users table in excel with region field. (I can add this table in secondary database)

LDAP Authentication is used.
Using views(raw SQL query is used), I am showing aggregated data of transaction table.
All users are seeing same data, as there is no filter on the region.
Now, I want to aggregate only those records which login user's region belongs to.
How can these implemented?
My approach:

Create region model
Implement a Foreign Key with transaction tables(Is it possible?)

What is best approach to this scenario?
Please explain clearly in steps.
NOTE: I have solved my problem. Please look my answer. Is there any drawbacks of my approach? (New best approach is appreciated)
I solved this by following below steps.
Steps:

Created a DataFrame of User Table present in excel using Pandas in my views.py.
Captured a login user ID into a variable.
Filtered this User ID in DataFrame and got his/her region and then I have passed this variable to final aggregating query and filtered there.

Short and simple.
Django: how to fetch records only that matches the region belongs to login user?