On Sep 13, 2010, at 2:13 PM, Alvaro Reinoso wrote:
> If I merge the updated channel like you can see in this piece of code
> it's working:
>
> def insertXML(channels, strXml):
> """Insert a new channel given XML string"""
> channel = Channel()
> session = rdb.Session()
>
> channel.fromXML(strXml)
> fillChannelTemplate(channel, channels)
> for item in channel.items:
> if item.id == 0:
> item.id = None
> break
> session.merge(channel)
>
> for chan in channels:
> if chan.id == channel.id:
> chan.items.append(item)
> break
>
> My problem is I'm using channels, it's a list of channels which I save
> it in HTTP session object. The channels list is a detached object
> which I get using joinload option. So in this case, I update the
> object correctly in database, but It isn't persistent in channels if I
> do this:
>
> for chan in channels:
> if chan.id == channel.id:
> chan.items.append(item)
> break
>
> Do you have any idea how I can solve this problem? or another
> approach?
here:
> session.merge(channel)
use the return value of merge():
channel = session.merge(channel)
the returned channel plus all children is the fully merged result.
>
> Thanks!
>
> On Sep 10, 5:09 pm, Michael Bayer <[email protected]> wrote:
>> On Sep 10, 2010, at 2:57 PM, Alvaro Reinoso wrote:
>>
>>
>>
>>> Hello guys,
>>
>>> I have this table:
>>
>>> class Channel(rdb.Model):
>>> rdb.metadata(metadata)
>>> rdb.tablename("channels")
>>
>>> id = Column("id", Integer, primary_key=True)
>>> title = Column("title", String(100))
>>> hash = Column("hash", String(50))
>>> runtime = Column("runtime", Float)
>>
>>> items = relationship(MediaItem, secondary="channel_items",
>>> order_by=MediaItem.position, backref="channels")
>>
>>> I have a list of channels, but they are detached objects. I get them
>>> using joinedload option because I maniputale those objects sometimes.
>>> When I do that, I update the object.
>>
>>> This time, I'm trying to add a new item to a detached channel object.
>>> This is the code:
>>
>>> def insertXML(channels, strXml):
>>> """Insert a new channel given XML string"""
>>> channel = Channel()
>>> session = rdb.Session()
>>> result = ""
>>
>>> channel.fromXML(strXml)
>>> fillChannelTemplate(channel, channels)
>>> if channel.id == 0:
>>> session.add(channel)
>>> session.flush()
>>> channels.append(channel)
>>> else:
>>> for chan in channels:
>>> if chan.id == channel.id:
>>> chan.runtime = channel.runtime
>>> chan.modified = datetime.date.today()
>>
>>> for item in channel.items:
>>> if item.id == 0:
>>> chan.items.append(item)
>>
>>> session.merge(chan)
>>
>>> The item is inserted in the database, but It doesn't create the
>>> relation in channel_items.
>>
>>> Besides, I get this error:
>>
>>> FlushError: New instance <Channel at 0xb75eeec> with identity key
>>> (<class 'zeppelinlib.channel.ChannelTest.Channel'>, (152,)) conflicts
>>> with persistent instance <Channel at 0xb598dec
>>
>> anytime you have that error you should be using merge() to merge state into
>> that which is already existing, the return value from merge() is then what
>> you need to use for your new state. I see you tried using merge earlier
>> but your issue is not clear.
>
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