python + SQLAlchemy：使用 Session 对象删除
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/26643727/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
python + SQLAlchemy: deleting with the Session object
提问by Wells
I can't quite figure this out: I'd like to delete all the records from a table on a matching query. Kind of like this.
我不太明白这一点：我想从匹配查询的表中删除所有记录。有点像这样。
engine = sqlalchemy.create_engine(string)
meta = MetaData(bind=engine)
meta.reflect(bind=engine, schema='myschema')
Base = automap_base(metadata=meta)
Base.prepare(engine, reflect=True)
Classes = Base.classes
Session = sessionmaker(bind=engine)
session = Session()
session.delete(plays.record_id == '123')
But that isn't working. What's the idea here? Error I get is:
但这不起作用。这里的想法是什么？我得到的错误是：
error in parsing record ID 020087: Class 'sqlalchemy.sql.elements.BinaryExpression' is not mapped
error in parsing record ID 020087: Class 'sqlalchemy.sql.elements.BinaryExpression' is not mapped
回答by muthan
In SQL Alchemy you are deleting Objects that you get with a query from the database. This you can do in 2 Ways:
在 SQL Alchemy 中，您正在删除通过查询从数据库中获得的对象。您可以通过 2 种方式执行此操作：
Deleting with query (will issue just one DELETEstatement):
使用查询删除（将只发出一个DELETE语句）：
session.query(User).filter(User.id==7).delete()
session.commit()
Deleting object instance returned by a query (will issue 2 statements: first SELECT, then DELETE):
删除查询返回的对象实例（将发出 2 个语句： first SELECT， then DELETE）：
obj=session.query(User).filter(User.id==7).first()
session.delete(obj)
session.commit()
回答by anand tripathi
Delete All Records
删除所有记录
#for all records
session.query(Model).delete()
session.commit()
Deleted Single Row
删除的单行
If you want to delete specific records then try filterclause in the query.
ex.
如果要删除特定记录filter，请在查询中使用try子句。前任。
#for specific value
session.query(Model).filter(Model.id==123).delete()
session.commit()
Delete Single Record by Object
按对象删除单条记录
record_obj = session.query(Model).filter(Model.id==123).first()
session.delete(record_obj)
session.commit()
https://flask-sqlalchemy.palletsprojects.com/en/2.x/queries/#deleting-records
https://flask-sqlalchemy.palletsprojects.com/en/2.x/queries/#deleting-records
