# databases链接数据库

from sqlalchemy import *
from sqlalchemy.orm import sessionmaker,declarative_base

# 导入.env参数
import os
from dotenv import load_dotenv
load_dotenv( )
DB_USER = os.getenv("DB_USER", "root")
DB_PASSWORD = os.getenv("DB_PASSWORD", "")
DB_HOST = os.getenv("DB_HOST", "localhost")
DB_PORT = os.getenv("DB_PORT", "3306")
DB_NAME = os.getenv("DB_NAME", "student_manage_system")

db_url = f"mysql+pymysql://{DB_USER}:{DB_PASSWORD}@{DB_HOST}:{DB_PORT}/{DB_NAME}?charset=utf8mb4"

engine_all = create_engine(db_url)

Base_all = declarative_base()

Session = sessionmaker(bind=engine_all
                               ,autoflush=False
                               ,autocommit=False)

def get_db():
    db = Session()
    try:
        yield db
    finally:
        db.close()