Django Migration is not applying the migration changes

Question

Using django 1.7.7 I want to use django\'s migration to add or remove a field. so I modified model.py and ran

python manage.py makemigrations myproj
Migrations f         


        

Answer 1

Similar to Andrew E above but with a few changes especially where you haven't deleted the migrations folder in your quest to resolve the issue

1 - In your intact migration folder just examine the 000*.py files counting from the highest down to initial.py till you find the one where your Model is defined, say 0002_entry.py

2 - python manage.py sqlmigrate app-name 0002 > 0002_sql.txt to capture the SQL commands

3 - Edit this file to ensure there are no hard CR/LFs and the ALTER, CREATE INDEX commands are each on own single line

4 - Log into your DB (I have Postgres) and run these commands

Answer 2

I find Django migrations a bit of a mystery, and tend to prefer external tools (liquibase, for example).

However, I just ran into this "No migrations to apply" problem as well. I also tried removing the migrations folder, which doesn't help.

If you've already removed the migrations folder, here's an approach that worked for me.

First, generate the new "clean" migrations:

$ python manage.py makemigrations foo
Migrations for 'foo':
  dashboard/foo/migrations/0001_initial.py
    - Create model Foo
    - Create model Bar

Then look at the SQL and see if it looks reasonable:

$ python manage.py sqlmigrate foo 0001
BEGIN;
--
-- Create model Foo
--
CREATE TABLE "foo" ("id" serial NOT NULL PRIMARY KEY, ... "created_at" timestamp with time zone NOT NULL, "updated_at" timestamp with time zone NOT NULL);
CREATE INDEX "..." ON "foo" (...);
COMMIT;

Then apply execute that same SQL on your database.

I'm using Postgres but it will be similar for other engines.

One way is to write the content to a file:

$ python manage.py sqlmigrate foo 0001 > foo.sql
$ psql dbname username < foo.sql
BEGIN
CREATE TABLE
CREATE INDEX
COMMIT

Another is pipe the SQL directly:

$ python manage.py sqlmigrate foo 0001 | psql dbname username

Or copy and paste it, etc.