如何将查询转换为Django ORM查询

Question

I am trying to figure out how I can convert the following query into a Djangon ORM query. I am using Django 2.1 Python 3.5 on windows, I am trying to run the query against a Oracle database

SELECT m.msg_no, q.seq, To_Char(m.date_created,'yyyy/mm/dd hh24:mi:ss'), To_Char(SYSDATE,'yyyy/mm/dd hh24:mi:ss'), q.name, Round((round(SYSDATE - m.date_created,6)*1440),1) AS msg_age  
FROM message m
INNER JOIN queue q ON m.queue = q.seq
WHERE m.date_created >= (SYSDATE - 13/24)
AND m.status1 = 0 
AND m.direction = 0;

I have two models, would like to know how to best, the tables Message and Queue are relate by Queue primary key SEQ and Message foreign key QUEUE, so SEQ == QUEUE in Message table:

from django.db import models

# Create your models here.
class Queue(models.Model):
  SEQ = models.IntegerField(primary_key=True,)
  NAME = models.CharField(max_length = 50)
  INPUT_DRIVER = models.IntegerField()
  OUTPUT_DRIVER = models.IntegerField()
  DIRECTION = models.IntegerField()
  ORIGINATOR = models.IntegerField()
  DESTINATOR = models.IntegerField()
  PRIORITY = models.IntegerField()
  INPUTEXEC = models.CharField(max_length = 100)
  OUTPUTEXEC = models.CharField(max_length = 100)
  USERID = models.CharField(max_length = 8)
  TMSTAMP = models.DateTimeField(max_length = 7)
  QUEUE_TYPE = models.CharField(max_length = 16)

  class Meta:
      db_table = "QUEUE"

# 
class Message(models.Model):
  MSG_NO = models.IntegerField(primary_key=True,)
  MSG_TYPE = models.IntegerField()
  DIRECTION = models.IntegerField()
  SESSION_NO = models.IntegerField()
  SEQUENCE_NO = models.IntegerField()
  REF_SESSION = models.IntegerField()
  REF_SEQUENCE = models.IntegerField()
  ACKTIME = models.DateTimeField(max_length = 7)
  ACKNAKSTATUS = models.IntegerField()
  PRIORITY = models.CharField(max_length = 1)
  DELIVMONITOR = models.IntegerField()
  OBSOLESCENCE = models.IntegerField()
  DISPOSITION = models.IntegerField()
  TRAILER = models.IntegerField()
  BYPASSED = models.IntegerField()
  RESPONSE_QUEUE = models.IntegerField()
  SOURCE_QUEUE = models.IntegerField()
  QUEUE = models.IntegerField()
  QUEUE_PRIORITY = models.IntegerField()
  DATE_CREATED = models.DateTimeField(max_length = 7)
  DATE_ROUTED = models.DateTimeField(max_length = 7)
  INPUT_FILE = models.IntegerField()
  OUTPUT_FILE = models.IntegerField()
  STATUS1 = models.IntegerField()
  STATUS2 = models.IntegerField()
  STATUS3 = models.IntegerField()
  USERID = models.CharField(max_length = 8)
  TMSTAMP = models.DateTimeField(max_length = 7)

  class Meta:
      db_table = "MESSAGE"

Answer 1

If you want to use Djangos ORM to build that query, you should use the relationship fields .

First, I suggest you change the field to this:

QUEUE = models.ForeignKey(to=Queue, on_delete=models.PROTECT)

And then try something like this:

import datetime
from django.utils import timezone as tz

now = tz.now()
filter_date = now - datetime.timedelta(hours=...something...)

qs = Message.objects.filter(
    STATUS1=0, DIRECTION=0, DATE_CREATED__gte=filter_date)

You may want to look into QuerySet.annotate() .

This still needs to be tweeked to fit your exact query, but my answer should but you on the right course to figure it out.