FastAPI+SQLAlchemy数据库连接
目录
配置数据库连接
python
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# db.py
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
DATABASE_URL = "mysql+pymysql://root:7997@localhost/fastapidemo"
engine = create_engine(
DATABASE_URL,
pool_size=10, # 设置连接池大小
max_overflow=20, # 设置连接池最大溢出连接数量
pool_timeout=30, # 设置连接超时时间
pool_recycle=1800, # 设置连接的回收时间
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
创建表模型
python
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from sqlalchemy import Column, Integer, String, ForeignKey, Table
from sqlalchemy.orm import DeclarativeBase, relationship
class Base(DeclarativeBase):
__abstract__ = True # 标记为抽象基类，防止直接创建表
@classmethod
def get_all(cls, session):
return session.query(cls).all()
book_press = Table('book_press', Base.metadata,
Column('book_id', Integer, ForeignKey('book.id'), primary_key=True),
Column('press_id', Integer, ForeignKey('press.id'), primary_key=True))
class Book(Base):
__tablename__ = 'book'
id = Column(Integer, primary_key=True, autoincrement=True)
title = Column(String(15), nullable=False, unique=True)
author_id = Column(Integer, ForeignKey('author.id'))
author = relationship('Author', backref='books', cascade='all,delete')
press = relationship('Press', backref='books', secondary=book_press)
class Author(Base):
__tablename__ = 'author'
id = Column(Integer, primary_key=True, autoincrement=True)
name = Column(String(15), nullable=False, unique=True)
age = Column(Integer, nullable=False)
class Press(Base):
__tablename__ = 'press'
id = Column(Integer, primary_key=True, autoincrement=True)
name = Column(String(15), nullable=False, unique=True)
if __name__ == '__main__':
from db import engine
Base.metadata.create_all(engine)
创建alembic迁移文件
安装+初始化
bash
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pip install alembic
bash
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alembic init alembic
python
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# env.py
from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
# 导入你的 Base 和模型
from module import Base, Book, Author, Press
config = context.config
# 默认None 替换成你的Base
target_metadata = Base.metadata
# 其他配置...
编辑alembic.ini
ini
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# alembic.ini
sqlalchemy.url = mysql+pymysql://root:7997@localhost/fastapidemo
迁移数据库
bah
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alembic revision --autogenerate
alembic upgrade head
视图函数查询
python
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# main.py
from fastapi import FastAPI, Request, Depends
from pydantic import BaseModel
from sqlalchemy.orm import Session
from db import SessionLocal
from orm import Author
app = FastAPI()
session = SessionLocal()
def get_db():
db = SessionLocal()
try:
yield db
finally:
db.close()
class Item(BaseModel):
pass
@app.get("/api/")
async def root(db: Session = Depends(get_db)):
# 直接用session查询
res = db.query(Author).all()
# 调用模型类的方法查询
res2 = Author.get_all(db)
print(res[0].name)
print(res2[0].name)
return {f"作者名：{res[0].name},{res2[0].name}"}