create model instance

[djangoer]

A quick newbie question,

is there any way that can create a default instance (a pre-specified
instance) in the database once the model is created. In other words,
when we first run the syncdb(or set up the website), an pre-defined
instance is created.

For example, we have a Book model,

class Book(models.Model):
author = models.CharField(maxlength = 50)
title = models.CharField(maxlength = 50)

When the website is first setup, we would like to have one default
"Book" instance in the DB, say Book("John.Smith","COMPUT101").

Your help is greatly appreciated.

[Chris Czub]

http://www.djangoproject.com/documentation/models/fixtures/

What you are looking for is an initial_data fixture. You need to serialize the default instance of the model you want as JSON and save it in initial_data.json and then it should prepopulate when you run syncdb.

[djangoer]

thanks very much Chris.

I googled and also find some related articles.

http://www.djangoproject.com/documentation/0.96/models/fixtures/
http://code.djangoproject.com/wiki/Fixtures

However, when I tried to reset and syncdb, I always had error
messages.

1.$ python manage.py reset myapp
Type 'yes' to continue, or 'no' to cancel: yes
Error: myapp couldn't be reset. Possible reasons:
* The database isn't running or isn't configured correctly.
* At least one of the database tables doesn't exist.
* The SQL was invalid.
Hint: Look at the output of 'django-admin.py sqlreset myapp'. That's
the SQL this command wasn't able to run.
The full error: ERROR: constraint
"reference_id_id_refs_id_4d6e9d1fab032af2" does not exist

2.$ python manage.py syncdb
Loading 'initial_data' fixtures...
Installing json fixture 'initial_data' from '/home/myproject/myapp/../
myapp/fixtures'.
Problem installing fixture '/home/myproject/myapp/../myapp/fixtures/
initial_data.json': ['This value must be either True or False.']

Please advise. Thanks much!

"Chris Czub" <chris.c...@gmail.com> wrote:
> http://www.djangoproject.com/documentation/models/fixtures/
>
> What you are looking for is an initial_data fixture. You need to serialize
> the default instance of the model you want as JSON and save it in
> initial_data.json and then it should prepopulate when you run syncdb.
>