sqlalchemy的使用三 連接池的使用

from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session
from models import Student,Course,Student2Course

engine = create_engine(
        "mysql+pymysql://root:123456@127.0.0.1:3306/s9day120?charset=utf8",
        max_overflow=0,  # 超過連接池大小外最多創建的連接
        pool_size=5,  # 連接池大小
        pool_timeout=30,  # 池中沒有線程最多等待的時間，否則報錯
        pool_recycle=-1  # 多久之后對線程池中的線程進行一次連接的回收（重置）
    )
SessionFactory = sessionmaker(bind=engine)
session = scoped_session(SessionFactory)


def task():
    """"""
    # 方式一：
    """
    # 查詢
    # cursor = session.execute('select * from users')
    # result = cursor.fetchall()

    # 添加
    cursor = session.execute('INSERT INTO users(name) VALUES(:value)', params={"value": 'wupeiqi'})
    session.commit()
    print(cursor.lastrowid)
    """
    # 方式二：
    """
    # conn = engine.raw_connection()
    # cursor = conn.cursor()
    # cursor.execute(
    #     "select * from t1"
    # )
    # result = cursor.fetchall()
    # cursor.close()
    # conn.close()
    """

    # 將連接交還給連接池
    session.remove()


from threading import Thread

for i in range(20):
    t = Thread(target=task)
    t.start()