常用的filter操作符
下面的这些操作符可以应用在filter函数中
equals:
query.filter(User.name == 'ed')
not equals:
query.filter(User.name != 'ed')
LIKE:
query.filter(User.name.like('%ed%'))
IN:
query.filter(User.name.in_(['ed', 'wendy', 'jack']))
works with query objects too:
query.filter(User.name.in_(
session.query(User.name).filter(User.name.like('%ed%'))
))
NOT IN:
query.filter(~User.name.in_(['ed', 'wendy', 'jack']))
IS NULL:
query.filter(User.name == None)
alternatively, if pep8/linters are a concern
query.filter(User.name.is_(None))
IS NOT NULL:
query.filter(User.name != None)
alternatively, if pep8/linters are a concern
query.filter(User.name.isnot(None))
AND:
use and_()
from sqlalchemy import and_
query.filter(and_(User.name == 'ed', User.fullname == 'Ed Jones'))
or send multiple expressions to .filter()
query.filter(User.name == 'ed', User.fullname == 'Ed Jones')
or chain multiple filter()/filter_by() calls
query.filter(User.name == 'ed').filter(User.fullname == 'Ed Jones')
OR:
from sqlalchemy import or_
query.filter(or_(User.name == 'ed', User.name == 'wendy'))
MATCH:
query.filter(User.name.match('wendy'))
增加数据
arricle = Article(title="aaa",content="bbb")
db.session.add(arricle)
db.session.commit()
查询数据
result = Article.query.filter(Article.title=='mark').first()
print(result.content)
1. query是从db.Model中继承来的
2. query.filter(Article.title=’xx’)过滤条件
3. first()取出查询结果的第一条数据 实际上就是一个Article对象
4. .all()是查询到的所有结果 是一个Article对象数组
修改数据
1. 查询到要改的数据 拿到Article对象
2. 更新 article1.title=’new title’
3. db.session.commit()
result = Article.query.filter(Article.title=='success').first()
old_title = result.title
result.title = 'success2018'
db.session.commit()
删除
1. 查出要删除的数据 拿到Article对象
2. db.session.delete(article)
3. db.session.commit()
result = Article.query.filter(Article.title=='success2018').first()
db.session.delete(result)
db.session.commit()
