DJANGO using SQLSERVER how do I trigger the procedures? - sql-server

Question

I'm using SQLSERVER as a database in a DJANGO project in college and I need to trigger my triggers and procedures through DJANGO, I've been looking for a few days to do this and I can not, can anyone help me?

Answer 1

In case anyone else ends up on this page, this is how I managed to do this... my interpretation of the question is how to have actions on the database trigger functions on the database end. My database backend is PostgreSQL but SQL being a standard, queries for MySQL and others should be about the same).
The solution is relatively simple. Once you do your first
python manage.py makemigrations
python manage.py migrate
Head over to your database manager of choice and look up the SQL query that generated the table on which you wish to have your trigger.
For example, your public.auth.users table creation query might look like this:
CREATE TABLE public.auth_user
(
id integer NOT NULL DEFAULT nextval('auth_user_id_seq'::regclass),
password character varying(128) COLLATE pg_catalog."default" NOT NULL,
last_login timestamp with time zone,
is_superuser boolean NOT NULL,
username character varying(150) COLLATE pg_catalog."default" NOT NULL,
first_name character varying(30) COLLATE pg_catalog."default" NOT NULL,
last_name character varying(150) COLLATE pg_catalog."default" NOT NULL,
email character varying(254) COLLATE pg_catalog."default" NOT NULL,
is_staff boolean NOT NULL,
is_active boolean NOT NULL,
date_joined timestamp with time zone NOT NULL,
CONSTRAINT auth_user_pkey PRIMARY KEY (id),
CONSTRAINT auth_user_username_key UNIQUE (username)
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;
Let's say you want to have a trigger to change the last_name of every new record to the value "Trump" (without quotation marks). The code to create your trigger function would look like this (N.B. the RAISE NOTICE lines just echo information to the SQL terminal for debugging. You can comment them out by adding a double dash in the front of them like --RAISE NOTICE 'id = % ', NEW.id;):
CREATE OR REPLACE FUNCTION trumpisizer() RETURNS trigger AS $$
BEGIN
RAISE NOTICE 'last_name = % ', NEW.last_name;
NEW.last_name = 'Trump';
RAISE NOTICE 'last_name = % ', NEW.last_name;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
Now you need to bind your function to your table. This SQL query to do so is this:
CREATE TRIGGER trumpist BEFORE INSERT ON auth_user FOR EACH ROW EXECUTE PROCEDURE trumpisizer();
Now load up your django app and create a new user. Every new user's last_name will be changed to the new value.

Answer 2

Slightly off topic advice, so please forgive me.
Why not use Flask. The power of Django is largely working within its framework. You build your database with models.py. You perform migrations through the framework and you leverage it for data operations with custom middleware or signals.
If you have a db that already does a lot of the heavy lifting for you, then it might be easier to work with less of a "batteries included" framework like Django and use flask or bottle. This would be especially true if it's for a college project where it doesn't require enterprise features or stability. Might be easier to hack and slash through some less well defined framework. If its towards the end of the semester, learning Django might be a tall order.

Answer 3

I'm just going to answer the question, but can tell you from experience, you're probably headed down some paths that are far off what would be considered best practices. You may want to do a little bit more digging if this is going to become a permanent project; if its a learning exercise, that's cool too!
On to the answer: Django is written in Python. You can trigger stored procedures in SQL Server from Python using pyodbc. To use SQL Server with Django's ORM, you'll want to use a Django engine, such as django-pyodbc-azure (install with pip install django-pyodbc-azure) which will also install pyodbc. If you're running Django on Linux or Mac, you'll also need a SQL Server compatible ODBC driver, such as the MS ODBC driver or FreeTDS (for up-to-date details on installing drivers on Linux: https://pyphilly.org/django-and-sql-server-2018-edition/)
Good luck.