python第三方庫之Django學(xué)習(xí)筆記二

Java3y 發(fā)布于2019-07-30 14:35 / 3095人閱讀

摘要：上一節(jié)項目框架已經(jīng)搭建完畢，現(xiàn)在開始連接數(shù)據(jù)庫，創(chuàng)建數(shù)據(jù)庫設(shè)置默認安裝了數(shù)據(jù)庫打開文件數(shù)據(jù)庫引擎數(shù)據(jù)庫的名字小貼士如果你選擇，數(shù)據(jù)庫是以文件的形式生成，要設(shè)置成絕對路徑創(chuàng)建表結(jié)構(gòu)創(chuàng)建模型激活模型執(zhí)行命令執(zhí)行成功后目錄結(jié)構(gòu)如下圖

上一節(jié)項目框架已經(jīng)搭建完畢，現(xiàn)在開始連接數(shù)據(jù)庫，創(chuàng)建model

1、數(shù)據(jù)庫設(shè)置
python默認安裝了sqlite數(shù)據(jù)庫

打開文件：dayang/settings.py

ENGINE – 數(shù)據(jù)庫引擎

     "django.db.backends.sqlite3", 
     "django.db.backends.postgresql", 
     "django.db.backends.mysql",
     "django.db.backends.oracle".

NAME – 數(shù)據(jù)庫的名字

小貼士：如果你選擇sqlite，數(shù)據(jù)庫是以文件的形式生成，name要設(shè)置成絕對路徑

By default, INSTALLED_APPS contains the following apps, all of which come with Django:

django.contrib.admin – The admin site. You’ll use it shortly.

django.contrib.auth – An authentication system.

django.contrib.contenttypes – A framework for content types.

django.contrib.sessions – A session framework.

django.contrib.messages – A messaging framework.

django.contrib.staticfiles – A framework for managing static files.

These applications are included by default as a convenience for the common case.

Some of these applications make use of at least one database table, though, so we need to create the tables in the database before we can use them. To do that, run the following command:
manage.py migrate # 創(chuàng)建表結(jié)構(gòu)

2、創(chuàng)建模型

3、激活模型
That small bit of model code gives Django a lot of information. With it, Django is able to:

Create a database schema (CREATE TABLE statements) for this app.
Create a Python database-access API for accessing Question and Choice objects.
But first we need to tell our project that the polls app is installed.

執(zhí)行命令：manage.py makemigrations polls
# By running makemigrations, you’re telling Django that you’ve made some changes to your models (in this case, you’ve made new ones) and that you’d like the changes to be stored as a migration.

執(zhí)行成功后目錄結(jié)構(gòu)如下圖：

Now, run migrate again to create those model tables in your database:

remember the three-step guide to making model changes:

Change your models (in models.py).
Run python manage.py makemigrations to create migrations for those changes
Run python manage.py migrate to apply those changes to the database.