SqlAlchemy and PostgreSql datetime update

Question

I have a PostgreSql table in which I want to update an attribute of type timestamp with timezone (I tried also without timestamp but it does not work). I'm using SqlAlchemy session for that purpose.

I fetch an existing record, and update it with a current timestamp:

from model import Table
from dbconf import session

t=session.query(Table).filter(Table.id==1).first()
t.available=datetime.now()
session.add(t)
session.commit()

After this command nothing change in the database. What am I doing wrong?

Miro K. · Accepted Answer · 2014-05-07 17:56:32Z

4

I can assume that you have model of this table, you should add there new update method like this:

class table(Base):
    __tablename__ = 'table'

    id = Column(Integer, primary_key=True)
    available = Column(DateTime)
    asd = Column(Unicode(255))


    def update(self, available=None, asd = None):  #etc.
        if available:
            self.available = available
        if asd:
            self.asd = asd

and updating happens then like this:

import transaction
with transaction.manager:
    t=session.query(Table).filter(Table.id==1).first() #search the object what you want to update
    t.update(available=datetime.now()) #you can update only one or several cell like this

edited May 7, 2014 at 17:56

answered May 7, 2014 at 10:12

Miro K.

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2 Comments

Miro K. Over a year ago

looks like thats it. but update should work without it too, only reason to use transaction is that, when something goes wrong, every changes made to db inside of transaction.manager, is rollbacked. So it's extra protection.

c0dezer019 Over a year ago

There shouldn't be any need for this. Either doing it where he currently tries to update to it and doing it here are going to be one in the same :/

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