使用 django 模型进行复杂查询

Question

I created a view in my database model with 6 joins and 10 columns, and at the moment it shows around 86.000 rows. I try to query all the rows by objects.all() and then filter according to user interaction (form data sent by POST and then choosing appropriate.filter(*args) querying) After that I tried to get the length of the queryset by using count() since this method doesnt evaluate the query. But since views don't have indexes on the columns, the count() method takes to long.

I searched for the solution of materializing the view but that isn't possible in mysql.

Then I searched for a solution that might be able to replace the initial.all() by just using the 6 joins and filtering arguments in django rather than creating a view, so the indexes would still be available. But I couldn't find a solution to that problem.

Or maybe combining every row from the view with another table so I can use the index of the other table for faster querying?:

SELECT * FROM View LEFT JOIN Table ON (View.id = Table.id)

I appreciate every answer

Answer 1

Try this below:

from django.db import models

# I think below is your table structure
class Table(models.Model):
    pass

class View(models.Model):
    table = models.ForeignKey(to=Table)

qs = View.objects.select_related('table').filter(table__isnull=True)
for iterator in qs:
    print(qs)

Thanks !