Question

I have models in Django set up as below.

class Pupil(models.Model):
    forename = models.CharField(max_length=30)
    surname = models.CharField(max_length=30)
    dateofbirth = models.DateField()
    year = models.IntegerField()
    class_group = models.CharField(max_length=30)
    email = models.EmailField(blank=True)
    assignments = models.ManyToManyField('Assignment', verbose_name='related assignments')

    def __unicode__(self):
        return u'%s %s' % (self.forename, self.surname)

class Subject(models.Model):
    name = models.CharField(max_length=30)
    level = models.CharField(max_length=30)
    teachers = models.ManyToManyField('Teacher', verbose_name='related teachers')

    def __unicode__(self):
        return self.name

class Teacher(models.Model):
    forename = models.CharField(max_length=30)
    surname = models.CharField(max_length=30)
    email = models.EmailField(blank=True)

    def __unicode__(self):
        return u'%s %s' % (self.forename, self.surname)

class Assignment(models.Model):
    assignment_name = models.CharField(max_length=30)
    date_assigned = models.DateField()
    date_submitted = models.DateField()

    def __unicode__(self):
        return self.assignment_name

When I attempt to add a pupil and attach an assignment to the pupil in the admin, I get a database error –

no such table: homework_pupil_assignments

after reading this I realised this could be due to django not updating changes to my models as when I do manage.py sqlall homework

I see the following:

BEGIN;
CREATE TABLE "homework_pupil_assignments" (
    "id" integer NOT NULL PRIMARY KEY,
    "pupil_id" integer NOT NULL,
    "assignment_id" integer NOT NULL,
    UNIQUE ("pupil_id", "assignment_id")
)
;
CREATE TABLE "homework_pupil" (
    "id" integer NOT NULL PRIMARY KEY,
    "forename" varchar(30) NOT NULL,
    "surname" varchar(30) NOT NULL,
    "dateofbirth" date NOT NULL,
    "year" integer NOT NULL,
    "class_group" varchar(30) NOT NULL,
    "email" varchar(75) NOT NULL
)
;
CREATE TABLE "homework_subject_teachers" (
    "id" integer NOT NULL PRIMARY KEY,
    "subject_id" integer NOT NULL,
    "teacher_id" integer NOT NULL,
    UNIQUE ("subject_id", "teacher_id")
)
;
CREATE TABLE "homework_subject" (
    "id" integer NOT NULL PRIMARY KEY,
    "name" varchar(30) NOT NULL,
    "level" varchar(30) NOT NULL
)
;
CREATE TABLE "homework_teacher" (
    "id" integer NOT NULL PRIMARY KEY,
    "forename" varchar(30) NOT NULL,
    "surname" varchar(30) NOT NULL,
    "email" varchar(75) NOT NULL
)
;
CREATE TABLE "homework_assignment" (
    "id" integer NOT NULL PRIMARY KEY,
    "assignment_name" varchar(30) NOT NULL,
    "date_assigned" date NOT NULL,
    "date_submitted" date NOT NULL
)
;
COMMIT;

I then installed South, following the directions to get up and running with an existing app, in the hope of successfully syncing these tables. No joy.

Can anyone suggest how I can get the database (sqlite3) to reflect the models or point out what I’m doing wrong?

Answer 1

Updated answer for Django migrations without south plugin:

Like T.T suggested in his answer, my previous answer was for south migration plugin, when Django hasn’t any schema migration features.
Now (works in Django 1.9+):

T.T wrote:

You can try this!

python manage.py makemigrations

python manage.py migrate --run-syncdb

---

Outdated for south migrations plugin

As I can see you done it all in wrong order, to fix it up your should
complete this checklist (I assume you can’t delete sqlite3 database
file to start over):

1. Grab any SQLite GUI tool (i.e. http://sqliteadmin.orbmu2k.de/)
2. Change your model definition to match database definition (best approach is to comment new fields)
3. Delete migrations folder in your model
4. Delete rows in south_migrationhistory table where app_name match your application name (probably homework)
5. Invoke: ./manage.py schemamigration <app_name> --initial
6. Create tables by ./manage.py migrate <app_name> --fake (--fake will skip SQL execute because table already exists in your database)
7. Make changes to your app’s model
8. Invoke ./manage.py schemamigration <app_name> --auto
9. Then apply changes to database: ./manage.py migrate <app_name>

Steps 7,8,9 repeat whenever your model needs any changes.