I have 2 databases on 2 different servers (say A & B).
I have some crawlers that use API functions to write data to database (A). Some of this data are new and others are just updates to previous rows. If some new rows are added to (A) I want to add id of these new rows to (B).
I want this to happen in real time without full scan of (A) iteratively. I want something like a trigger in (A) to send new ids to (B). How should I do write this trigger?(If you think there is a better solution, please help me)
you can do it by using django signals. Signals means just like trigger. if you want do any operation while creating updating deleting models. you can use signals. django reference reference example
suppose you have two models named:
class A(models.Model):
name = models.CharField(max_length=128)
class B(models.Model):
a = models.ForeignKey(A)
save this file in your app/signals.py
from django.db.models.signals import post_save
from .models import A,B
def create_b(sender, instance, created, *args, **kwargs):
if created:
B.objects.create(a=instance)
post_save.connect(create_b, sender=A)
and inorder to work this signals properly you have to call it in apps config.
and in app.py file copy this
class ProductConfig(AppConfig): #this will be different
name = 'product' # this will be different based on your app name
#copy below lines only
def ready(self):
from .signals import *
and in your app's __init__.py file include this line
default_app_config = "product.apps.ProductConfig"