flask_query
1. 添加一条数据:
art = Artical(title='python',content='开发程序', author='haha')
session.add(art)
session.commit()
2.添加多条数据:
art1 = Artical(title='java',content='开发程序', author='keke')
art2 = Artical(title='C#',content='开发程序', author='jjjj')
session.add_all([art1,art2])
session.commit()
3.查询数据:
# all 查询所有
# data = session.query(Artical).all()
# 通过filter方法来查询数据
# data = session.query(Artical).filter(Artical.title=='python').all()
# for d in data:
# print(d.content)
# print(d.title)
# 通过filter_by()方法来查询数据
# data = session.query(Artical).filter_by(title='python').all()
# for d in data:
# print(d.content)
# print(d.title)
# data = session.query(Artical).first()
# print(data.title)
4.删除数据:
data = session.query(Artical).first()
session.delete(data)
session.commit()
5.更新数据:
data = session.query(Artical).first()
data.title = 'hahah'
session.commit()
6.flask——query:
from sqlalchemy.orm import sessionmaker
from sqlalchemy import func
# 聚合函数
# result = session.query(func.count(Artical.id)).first()
# print(result)
# result = session.query(func.avg(Artical.price)).first()
# print(result)
# result = session.query(func.max(Artical.price)).first()
# print(result)
result = session.query(func.sum(Artical.price)).first()
print(result)
nullable是否为空, nullable=False 不允许为空
unique 是否唯一, 存放的内容 是惟一的
query的可选参数:
func.count() 统计数量