【Flask】Sqlalchemy 增删该查操作

### sqlalchemy 增删改查操作， 通过session来进行操作。

# coding:utf-8
# Author: liangjun.

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

HOSTNAME = '127.0.0.1'
PORT = 3306
DATABASE = 'sqlalchemy_first'
USERNAME = 'root'
PASSWORD = '123456'

DB_URI = 'mysql+pymysql://{username}:{password}@{host}:{port}/{dbname}?charset=utf8'.format(
        username=USERNAME, password=PASSWORD, host=HOSTNAME, port=PORT, dbname=DATABASE
)
engine = create_engine(DB_URI)
Base = declarative_base(engine)
Session = sessionmaker(engine)
session = Session()


# 创建ORM模型
class Person(Base):
    __tablename__ = 'person'
    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(length=50))
    age = Column(Integer)

    def __repr__(self):
        return "Person<name:{}, age{}>".format(self.name, self.age)


def add_data():
    p1 = Person(name='saber', age=18)
    p2 = Person(name='slamdunk', age=18)
    # 添加一条
    session.add(p1)
    # 添加多条记录
    session.add(p1, p2)
    session.commit()


def update_data():
    person = session.query(Person).first()
    person.name = 'saber007'
    session.commit()


def search_data():
    # 查找所有
    persons_1 = session.query(Person).all()
    for person in persons_1:
        print person

    # filter_by
    persons_2 = session.query(Person).filter_by(name='saber').all()
    for _p in persons_2:
        print _p

    # filter
    persons_3 = session.query(Person).filter(Person.name == 'saber').all()
    for _p in persons_3:
        print _p

    # get
    # 根据主键查找, 如没有则返回None
    person = session.query(Person).get(1)
    print "---------------get------------------"
    print person

    # first
    # 获取结果集中的第一条
    person = session.query(Person).first()
    print person


def delete_data():
    person = session.query(Person).first()
    session.delete(person)
    session.commit()

if __name__ == "__main__":
    # add_data()
    # search_data()
    # update_data()
    delete_data()