I have a custom app which I wanted to start using South with. It uses a FK for associating a blog entry from another app (proprietary, not written by me). Problem is when I try to run the initial schemamigration I get an error that some of the blog entry app's fields cannot be frozen. The fields that can't be frozen are fields that uses custom fields extended off of the core fields.
./manage.py schemamigration free --initial
I read South's docs on extending introspection but I don't know where/how to define the introspection rules.
Thanks in advance for any suggestions.
Have you tried the South Field Triple approach instead?
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I spin up a django project. Afterwards, i didn't write models.py but instead I created a database from MySQL command line(independent from django) and created three tables with required columns. Finally i connected my django app with that database successfully. I applied migrations. But now i am confused do i need to write models.py with every field name as in column?
I remember implementing a basic project in which i did write models.py and created database using "python manage.py shell" and then put values using
"from polls.models import Choice, Question"? How do i put data now initially and then using python on some action from UI?
Do i need models.py even for ready made mysql databases?
You do not need to construct models. Some (small) webservers are even completely stateless, and thus do not use a database. But a large part of how Django can help you is based on models.
You can write your own queries, forms, etc. But often by using a ModelForm, Django can for example remove a large amount of boilerplate code. It will make it furthermore less likely that there are mistakes in your code. So although not strictly necessary, the models are usually a keystone in how Django can help you.
You can use the inspectdb [Django-doc] command to inspect the database, and let Django "sketch" the models for you. Usually you will have still some work. Since Django can, for example, not derive that a field is an EmailField, since both a CharField and EmailField look exactly the same at the database side.
You do not need to use inspectdb however. You can construct your own models. If you create your own models, but these exist already at the database side, you might want to set managed = False [Django-doc] in the Meta of your model, to prevent Django from constructing migrations.
I created my database using python manage.py syncdb And I tried to add another attribute to my model called created_date My site gives error. And I deleted my db.sqlite3 file Then reorganize my model Then error went. I want to know is this correct
As the comment says migrations are the way to do this. Native migrations were only introduced in Django 1.7 but, since you're using syncdb, I'm guessing you're using an earlier version.
For earlier versions of Django you need a third-party app called South to handle migrations for you. This will then let you change your database after creation fairly painlessly in most cases.
After you initially create the model and you want to change the fields in the models. If you syncdb ,it replies no fixtures found, meaning to say the models has not recognised the change. One way to solve this is to delete the database and recreate the database but you lose all the data. Is there any other better solution? Thanks...
Use south to help you for models changes. It will automatically detect any changes to models and generate appropriate script to update db schema.
I use South for schema and data migraton for my Django site. I'm happy about using it. One day I converted models.py file to models/__init__py and put some additional models at models/something.py. When I ran python manage.py schemamigration app --auto, I got the Nothing seems to have changed. message despite of the new classes at something.py. If I copied them to the __init__py file, South had recognized the new models. I tried to import everything from something in the top of __init__py, but no change.
It's Django design. Django is not picking your models at all, you need to set app_label in your model's Meta class.
See ticket on Automatically discover models within a package without using the app_label Meta attribute.
I just created all the DB tables from one model with 6 classes.
In one of them I would like to add a NEW field.
I did that and hit: python manage.py syncdb.
But Django won't add that column in that table.
Am I missing something?
How can i add columns/tables AFTER I already created the db in Django.
Thanks!
You need to use a migration tool such as South.
Chapter 10 of the Django book has a section called 'Making Changes to a Database Schema' with a sub-section titled 'Adding Fields'...