Day4-编写Model
在day3的实战中,我们编写了ORM,在ORM模块里我们编写了Model类,这是一个基类,定义了一些基本的类方法。今天要写的Model是对昨天的Model再进行抽象。我们的网站目标是搭建一个博客,因此我们我们要创建User, Blog和Comment三个不同的model,并初始化三个数据库表。
Models.py:
import time, uuid
from orm import Model, StringField, BooleanField, FloatField, TextField
def next_id(): #随机生成id的方法
return '%015d%s000' % (int(time.time()*1000), uuid.uuid4().hex)
class User(Model):
__table__ = 'users'
id=StringField(primary_key=True, default=next_id, ddl='varchar(50)')
email = StringField(ddl='varchar(50)')
passwd = StringField(ddl='varchar(50)')
admin = BooleanField()
name = StringField(ddl='varchar(50)')
image = StringField(ddl='varchar(500)')
created_at = FloatField(default=time.time)
class Blog(Model):
__table__ = 'blogs'
id = StringField(primary_key=True, default=next_id, ddl='varchar(50)')
user_id = StringField(ddl='varchar(50)')
user_name = StringField(ddl='varchar(50)')
user_image = StringField(ddl='varchar(500)')
name = StringField(ddl='varchar(50)')
summary = StringField(ddl='varchar(200)')
content = TextField()
created_at = FloatField(default=time.time)
class Comment(Model):
__table__ = 'comments'
id = StringField(primary_key=True, default=next_id, ddl='varchar(50)')
blog_id = StringField(ddl='varchar(50)')
user_id = StringField(ddl='varchar(50)')
user_name = StringField(ddl='varchar(50)')
user_image = StringField(ddl='varchar(500)')
content = TextField()
created_at = FloatField(default=time.time)
#测试部分
if __name__== '__main__':
async def test():
await orm.create_pool(loop,user='www-data', password='www-data', db='awesome')
u = User(name='Test', email='[email protected]', passwd='123456780', image='about:blank')
await u.save()
a = await u.findall() #这个要打印才显示出来
print(a)
loop = asyncio.get_event_loop()
loop.run_until_complete(test())
orm.__pool.close() #在关闭event loop之前,首先需要关闭连接池。
loop.run_until_complete(orm.__pool.wait_closed())#在关闭event loop之前,首先需要关闭连接池。
loop.close()
初始化数据库表 schema.sql:
drop database if exists awesome;
create database awesome;
use awesome;
grant select, insert, update, delete on awesome.* to 'www-data'@'localhost' identified by 'www-data';
create table users (
`id` varchar(50) not null,
`email` varchar(50) not null,
`passwd` varchar(50) not null,
`admin` bool not null,
`name` varchar(50) not null,
`image` varchar(500) not null,
`created_at` real not null,
unique key `idx_email` (`email`),
key `idx_created_at` (`created_at`),
primary key (`id`)
) engine=innodb default charset=utf8;
create table blogs (
`id` varchar(50) not null,
`user_id` varchar(50) not null,
`user_name` varchar(50) not null,
`user_image` varchar(500) not null,
`name` varchar(50) not null,
`summary` varchar(200) not null,
`content` mediumtext not null,
`created_at` real not null,
key `idx_created_at` (`created_at`),
primary key (`id`)
) engine=innodb default charset=utf8;
create table comments (
`id` varchar(50) not null,
`blog_id` varchar(50) not null,
`user_id` varchar(50) not null,
`user_name` varchar(50) not null,
`user_image` varchar(500) not null,
`content` mediumtext not null,
`created_at` real not null,
key `idx_created_at` (`created_at`),
primary key (`id`)
) engine=innodb default charset=utf8;
将以上代码保存为sql文件后,在命令行下或者可视化工具中执行该文件即可。
注意:该操作前提是需要提前手动创建名为 awesome 的数据库
小结
至此,我们完成了ORM与Model的编写,像之前所说的,相当于在程序中创建了一个虚拟数据库,在以后的开发中,我们只需要对User Blog Comment三个Model进行操作就可以了,而不需要再去关心他们是如何去与数据库交互的。这就是封装的好处,也是ORM广为采用的原因。