Develop Reference

How to migrate existing table using Django and Python

I need one help. I have one existing mysql table in my localhost database and I need it to migrate using Django and Python. Here is my code:
settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'djangotest',
'USER': 'root',
'PASSWORD': '',
'HOST': '',
'PORT': '',
}
}
I am giving my table structure below.
Person:
id name phone age
models.py:
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models
# Create your models here.
class Person(models.Model):
name = models.CharField(max_length=200)
phone = models.CharField(max_length=15)
age = models.IntegerField()
Actually I am new to Django and Python and here I need to know command which can migrate the existing table.

to create migrations you need to use this command -
python manage.py makemigrations
the above command will create a file inside the migrations folder in your app directory and
to create/update table using the migration file in the database
python manage.py migrate
The above command will create/update a table in your DB.
Django Migration Docmentation
Let me know, if this is what you want!

In reference to akhilsp, I did not have to worry about table names using the _ format. Using the inspectdb command returned a Meta data for whatever the current table name is that I used in my model.
class Meta:
managed = False
db_table = 'malware'

Add --fake option to migrate command:
--fake
Tells Django to mark the migrations as having been applied or unapplied, but without actually running the SQL to change your
database schema.
This is intended for advanced users to manipulate the current
migration state directly if they’re manually applying changes; be
warned that using --fake runs the risk of putting the migration state
table into a state where manual recovery will be needed to make
migrations run correctly.
If you just start django project and didn't have initial migration: comment your Person model, make initial migration, apply it, uncomment Person, make migration for Person and at last migrate Person with --fake option.

You can use inspectdb command from the shell.
python manage.py inspectdb
This will print models corresponding to the current database structure. You copy the required model, make changes like adding validations, and then add other models.
python manage.py makemigrations will create migrations, and
python manage.py migrate will apply those migrations.
N.B: Your table name should be in the format "appname_modelname" where appname is name for django app name (not project name).

python manage.py migrate relation "" does not exist

I have 2 models - Facility and Slot.
class Facility(BaseModel):
name = models.CharField()...
class Slot(BaseModel):
name = models.CharField()...
slot = models.ForeignKey(Facility)
These work perfectly fine.
Now I am adding another model:-
class BlockedSlot(BaseModel):
slots = models.ManyToManyField(Slot)
Now when I run python manage.py makemigrations, it successfully creates a migration file.
But when I run python manage.py migrate, it gives the error - relation "facilities_slot" does not exist.
(models are in facilities.py)
I even tried resetting the db and trying, but it still fails.
I even deleted all the existing migrations and reran makemigrations that generated the 0001_initial.py and again ran migrate, but still fails.

Model Changes Django, Mezzanine, South

My model was
class Author(Page):
dob = models.DateField("Date of birth")
i removed dob field and updated model with:
class Author(Page):
name = models.CharField(max_length = 250)
email = models.EmailField()
Then entered two commands:
python manage.py schemamigration project_name 001_initial--add-field Author.name, Author.email
then this command
python manage.py migrate project_name
you can see attach image : these above commands don't allow me to save changes in models.
Need your assistance!

SOLUTION:
1)Before adding your new field go to command prompt and move to directory where your project or application is . Now write this command before adding fields in models.py file python manage.py schemamigration your_project_or_app_name --initial
2)Now write this command python manage.py migrate your_project_or_app_name --fake 0001 (or whichever migration number it returned - 0001 is you migration number) to set the south database to that state (tables already created).
3)Now go to your models.py file an add your new fields in your models.py file, then in your cmd run this command python manage schemamigration your_project_or_app_name --auto
4)Last step to save changes run this last migrate command python manage.py migrate your_project_or_app_name
Solution Reference :Django & South: Adding new field but DatabaseError occurs "table already exists" by Yuji 'Tomita' Tomita

Django, South, and Guardian: Migrate

I have two users, mh00h1 and mh00h2. I also have modelA that defines the following in my models.py:
class Meta:
permissions = (
('read','read'),
('write','write'),
)
From a shell, I went to set permissions:
>>>> frhde = create modelA instance
>>>> assign_perm('read', mh00h2, frhde)
DoesNotExist: Permission matching query does not exist. Lookup parameters were {'codename': u'read', 'content_type': <ContentType: modelA>}
I realized that South didn't migrate my models after I added class Meta to modelA and confirmed this. Changing read to read2 shows that South does not detect the change.
$ /manage.py schemamigration myapp --auto
Running migrations for myapp:
- Nothing to migrate.
- Loading initial data for myapp.
Installed 0 object(s) from 0 fixture(s)
Running migrations for guardian:
- Nothing to migrate.
- Loading initial data for guardian.
Installed 0 object(s) from 0 fixture(s)
How can I get schematicmigration to correctly update the database, or is there a better way to do this that does not require redoing the whole database?
Thank you.

You can use ./manage.py syncdb --all, or create a signal like in this post.

django south is changing my boolean data on init

To output my database to json file I would usually do
python manage.py dumptdata --indent=4 > mydata.json
However upon executing the following two commands to setup south:
python manage.py schemamigration myproj --initial
python manage.py migrate myproj --fake
I noticed that two of my booleans in mytable for an entry were switched from FALSE to TRUE! I see that from my GUI Web Interface interacting with the database however to more closely compare what changed and got corrupted I'd like to compare json to json but with south enabled I can no longer use the above command as it tells me
Not synced (use migrations):
- myproj
My table that had entries affected is below, I could have more affected data that I have not uncovered.
class MyConfig(models.Model):
name = models.CharField(max_length=64)
myConfigName = models.CharField(max_length=64, unique=True)
myA = models.ForeignKey(MyA)
myB = models.ForeignKey(MyB)
myBoolA = models.BooleanField()
myBoolB = models.BooleanField()
myBoolC = models.BooleanField()
class Meta:
unique_together = ('name', 'myA', 'myB')
def __unicode__(self):
return '%s_%s_%s' % (self.myA.name, self.myB.name, self.name)

schemamigration and migrate --fake don't modify the database. Do you have any initial_data fixture that could be reloaded when migrating? See https://docs.djangoproject.com/en/1.3/howto/initial-data/
Try to migrate with:
python manage.py migrate --no-initial-data
see south doc for more info about options

I don't think that either an --initial or a --fake should alter the database at all, so I'm surprised that it would modify data. In terms of why you're getting the "Not synced (use migrations)" error, I think it's likely because you faked the initial migration.
Try un-migrating the --fake and re-applying the initial migration with
python manage.py migrate --fake zero
python manage.py migrate
Then, you should be able to do the dumptdata