Django note2

·User model

The User model is already defined inside a built-in app named auth, which is listed in our INSTALLED_APPS configuration under the namespace django.contrib.auth.

·models

-in models.py ,each class will be transformed into database tables.

-Each field is represented by instances（实例） of django.db.models.Field subclasses (built-in Django core) and will be translated into database columns.（转换为数据表中的一列）

-use

python manage.py makemigrations

python manage.py sqlmigrate boards 0001

创建sql语句

python manage.py migrate

创建表

-create new object

board = Board(name='Django', description='This is a board about Django.')

To persist this object in the database, we have to call the save method:

board.save()

-special attribute

Every Django model comes with a special attribute; we call it a Model Manager. You can access it via the Python attribute objects

Board.objects.all() Board.objects.get() Board.objects.create()