fastapi Tortoise-ORM、SQLAlchemy、peewee使用orm查询user数据表里面admin用户的例子

好的，以下是使用三个不同 ORM 查询 `user` 表中 `admin` 用户的例子：

### 1. 使用 Tortoise-ORM

from tortoise.queryset import QuerySet
from tortoise.contrib.pydantic import pydantic_model_creator
from tortoise import Tortoise, fields, run_async


class User(models.Model):
    id = fields.IntField(pk=True)
    username = fields.CharField(max_length=50)
    password = fields.CharField(max_length=50)

    class Meta:
        table = "user"

async def main():
    await Tortoise.init(db_url='sqlite://db.sqlite3', modules={'models': ['__main__']})
    await Tortoise.generate_schemas()

    user_schema = pydantic_model_creator(User, exclude=('id',))
    queryset: QuerySet[User] = User.filter(username='admin')
    results = await user_schema.from_queryset_single(queryset)
    print(results)

    await Tortoise.close_connections()

run_async(main())

### 2. 使用 SQLAlchemy

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class User(Base):
    __tablename__ = 'user'

    id = Column(Integer, primary_key=True)
    username = Column(String(50))
    password = Column(String(50))

    def __repr__(self):
        return f"<User(username='{self.username}', password='{self.password}')>"

engine = create_engine('sqlite:///db.sqlite3')
Session = sessionmaker(bind=engine)

def main():
    session = Session()

    user = session.query(User).filter(User.username == 'admin').first()
    print(user)

    session.close()

if __name__ == '__main__':
    main()

### 3. 使用 peewee

from peewee import SqliteDatabase, Model, CharField, IntegerField

db = SqliteDatabase('db.sqlite3')

class User(Model):
    username = CharField(max_length=50)
    password = CharField(max_length=50)

    class Meta:
        database = db
        table_name = 'user'

def main():
    db.connect()
    db.create_tables([User])

    user = User.select().where(User.username == 'admin').first()
    print(user)

    db.close()

if __name__ == '__main__':
    main()

注意：以上三个例子都是基于 SQLite 数据库的。如果使用其他数据库，请参考相应 ORM 的文档进行配置。