Python中的ORM工具：Peewee

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上一篇文章介绍了Pyhton中的ORM工具：SQLAlchemy。本文延续之前的风格，介绍另一个ORM模块：Peewee，希望通过简单的CRUD示例可以帮助大家快速上手。

环境说明

• python v3.6.5
• peewee v3.7.0
• faker v0.9.1(生成伪造数据)

安装环境

	pip install peewee faker

CRUD示例

同样的，Peewee也支持绝大多数关系型数据库，示例中使用的是PostgreSQL，用法及说明大多已在源代码中注释，请具体参考如下：

from peewee import *
from faker import Factory
from datetime import datetime

# Create an instance of a Database
db = PostgresqlDatabase(database="postgres", host="localhost",
                        port=5432, user="postgres", password="password", )


# Define a model class
class User(Model):
    # If none of the fields are initialized with primary_key=True,
    # an auto-incrementing primary key will automatically be created and named 'id'.
    id = PrimaryKeyField()
    email = CharField(index=True, max_length=64)
    username = CharField(unique=True, max_length=32)
    password = CharField(null=True, max_length=64)
    createTime = DateTimeField(column_name="create_time", default=datetime.now)

    class Meta:
        database = db
        table_name = 'tb_user'
        # If Models without a Primary Key
        # primary_key = False

    def __str__(self) -> str:
        return "User(id：{} email：{} username：{} password：{} createTime: {})".format(
            self.id, self.email, self.username, self.password, self.createTime)


db.connect()
db.drop_tables([User])
db.create_tables([User])

""" CREATE """

# 创建User对象
user = User(email="[email protected]", username="张三", password="zs")
# 保存User
user.save()

# 创建faker工厂对象
faker = Factory.create()
# 利用faker创建多个User对象
fake_users = [{
    'username': faker.name(),
    'password': faker.word(),
    'email': faker.email(),
} for i in range(5)]
# 批量插入
User.insert_many(fake_users).execute()

""" RETRIEVE/GET/FIND """

user = User().select().where(User.id != 1).get()
print(user)
user = User.select().where(User.username.contains("张")).get()
print(user)
count = User.select().filter(User.id >= 3).count()
print(count)
users = User.select().order_by(User.email)
for u in users:
    print(u)

""" UPDATE """

effect_count = User.update({User.username: "李四", User.email: "[email protected]"}).where(User.id == 1).execute()
print(effect_count)

""" DELETE """

effect_count = User().delete_by_id(6)
print(effect_count)
effect_count = User.delete().where(User.id >= 4).execute()
print(effect_count)

参考链接

peewee 3.7.0 documentation

示例源码
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