Adding, deleting, checking and modifying MySQL database

Then my last article continues: MySQL database operation

In the previous article, we created a data table.
Now we need to add, delete, query, and modify data to the data table

One, create a session

Create a session object; similar to the cursor in pymysql, detect the position of our sql statement

from sqlalchemy.orm import sessionmaker
base.metadata.create_all(db)
s = sessionmaker(bind = db)
session = s()

Single statement insertion

# 二、单条语句插入
user = User(id = 1,name = "zhangsan",addree = "beijing",age = 20)
session.add(user)
session.commit()

Multiple inserts

    session.add_all([
    User(id = 2,name = "lisi",addree = "chaoyangqu",age = 23),
    User(id = 3,name = "lisi",addree = "chaoyangqu",age = 23),
    User(id = 4,name = "lihua",addree = "chaoyangqu",age = 26)]
    )
    session.commit()

Query all data

    result = session.query(User).all()
    for r in result:
        print(r.name,r.age)

Query a single piece of data

    result = session.query(User).get(1)
    print(result.name,result.age)

Conditional query

    result = session.query(User).filter_by(name = "zhangsan")
    for i in result:
        print(i.name)
        print(i.age)

change the data

    result = session.query(User).get(1)
    print(result.age)
    result.age = 20
    session.commit()
    print(result.age)

delete data

    result = session.query(User).get(1)
    session.delete(result)
    re = session.query(User).all()

The complete code:

import sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
#创建链接
#mysql://scott:tiger@hostname/dbname
db = sqlalchemy.create_engine("mysql://root:root@localhost/sqlorm")


#创建基类
base = declarative_base((db))

#创建数据表
class User(base):
    __tablename__ = 'user'
    id = sqlalchemy.Column(sqlalchemy.Integer,primary_key = True)
    name = sqlalchemy.Column(sqlalchemy.String(32))
    addree = sqlalchemy.Column(sqlalchemy.String(32))
    age = sqlalchemy.Column(sqlalchemy.Integer)
    
class UserInfo(base):
    __tablename__ = 'userinfo'
    id = sqlalchemy.Column(sqlalchemy.Integer,primary_key = True)
    phone = sqlalchemy.Column(sqlalchemy.String(11))
    user = sqlalchemy.Column(sqlalchemy.Integer,sqlalchemy.ForeignKey('user.id'))

if __name__=="__main__":
    # 一、创建会话
    #创建一个会话对象;类似pymysql中的游标,检测我们的sql语句位置
    base.metadata.create_all(db)
    s = sessionmaker(bind = db)
    session = s()
    
    

    # 二、单条语句插入
    # user = User(id = 1,name = "zhangsan",addree = "beijing",age = 20)
    # session.add(user)
    # session.commit()
    
    # 三、多条语句插入
    # 多条语句的插入,使用add_all()方法，数据用列表形式
    # session.add_all([
    # User(id = 2,name = "lisi",addree = "chaoyangqu",age = 23),
    # User(id = 3,name = "lisi",addree = "chaoyangqu",age = 23),
    # User(id = 4,name = "lihua",addree = "chaoyangqu",age = 26)]
    # )
    # session.commit()
    
    
    #四、查询所有的数据
    #惰性特质
    # result = session.query(User).all()
    # for r in result:
    #     print(r.name,r.age)
    
    # 五、查询单条数据
    # get()方法使用主键查询,参数输入id
    # result = session.query(User).get(1)
    # print(result.name,result.age)
    
    #六、条件查询
    # result = session.query(User).filter_by(name = "zhangsan")
    # for i in result:
    #     print(i.name)
    #     print(i.age)
    
    # 七、修改数据,首先使用get()获取数据,然后直接使用.加字段名的方法修改
    # result = session.query(User).get(1)
    # print(result.age)
    # result.age = 20
    # session.commit()
    # print(result.age)

    # 八、删除数据
    # result = session.query(User).get(1)
    # session.delete(result)
    # re = session.query(User).all()