本文介绍了SqlAlchemy(Flask + Postgres):如何仅更新json字段的特定属性?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个表,其中的一列声明为json,我需要通过将键值添加到json值来更新记录.
I have a table that has one column declared as a json and I need to update records by adding a key-value to the json value.
模型
class User(db.Model): __tablename__ = 'users' loginId = db.Column(db.String(128), nullable=False, primary_key=True) _password = db.Column(db.String(128), nullable=True) views = db.Column(JSON, nullable=True)控制器
@mod_event.route('/view', methods=['POST']) def view(): try: params = request.json loginId = params['dream']['loginId'] users.update().\ where(users.c.loginId==loginId).\ values(views=<query>))假定views中的当前值为{'1001':1} 如果必须将views更新为-
Assume current value in views is {'1001' : 1} What should be the query if views has to be updated to -
- {'1001':2}
- {'1001':1,'1002':1}
如果我不想先查询该值,请更改并更新回来.
if i don't want to query the value first, change and update back.
我很难确定如何在单个查询中执行此操作,请帮忙,谢谢!
I'm having a hard time figuring how to do this in a single query, please help, thanks!
推荐答案如果使用的是JSONB,则可以使用jsonb_set函数
if you are using JSONB, you can use the jsonb_set function
(table .update() .values(views=func.jsonb_set(table.c.views, '{%s}' % '1002', 1)) .where(...))如果您要从其他列插入
(table .update() .values(views=func.jsonb_set(table.c.views, '{%s}' % '1002', other_table.c.other_column.cast(String).cast(JSONB))) .where(...))更多推荐
SqlAlchemy(Flask + Postgres):如何仅更新json字段的特定属性?
发布评论