[sqlalchemy] Re: Updating a detached object

[Alvaro Reinoso]

Channel is just type of object. I realize what my problem is. I don't
know why my object isn't saved correctly.

for chan in channels:
if chan.id == channel.id:
 chan = session.merge(channel)
 break

On Sep 13, 2:47 pm, Michael Bayer mike...@zzzcomputing.com wrote:
 On Sep 13, 2010, at 2:31 PM, Alvaro Reinoso wrote:

  Yes, I've done that. I doesn't work either.

                     for chan in channels:
                             if chan.id == channel.id:
                                     chan = session.merge(channel)
                                     break

 i dont understand the context of that code (what's channel) ?

 This is how a basic merge works:

 def merge_new_data(some_xml):
      my_objects = parse_xml(some_xml)

    # at this point, every object in my_objects should
    # have a primary key, as well as every child of every element,
    # all the way down.   Existing primary keys must be fully populated,
    # that's your job.  This is the intricate part, obviously.  But you don't
    # merge anything here, just get the PKs filled in.

    # then you merge the whole thing.   merge() cascades along all
    # relationships.   The rule is simple - if PK is present and exists in the 
 DB, it
    # updates.  otherwise, it inserts.

    for obj in my_objects:
        Session.merge(obj)
    Session.commit()

   # done



  On Sep 13, 2:27 pm, Michael Bayer mike...@zzzcomputing.com wrote:
  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 mike...@zzzcomputing.com 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:

  

[sqlalchemy] Re: Updating a detached object

[Alvaro Reinoso]

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?

Thanks!

On Sep 10, 5:09 pm, Michael Bayer mike...@zzzcomputing.com 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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Re: [sqlalchemy] Re: Updating a detached object

[Michael Bayer]

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 mike...@zzzcomputing.com 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.
 
 -- 
 You received this message because you are subscribed to the Google Groups 
 sqlalchemy group.
 To post to this group, send email to sqlalch...@googlegroups.com.
 To unsubscribe from this group, send email to 
 sqlalchemy+unsubscr...@googlegroups.com.
 For more options, visit this group at 
 http://groups.google.com/group/sqlalchemy?hl=en.
 

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[sqlalchemy] Re: Updating a detached object

[Alvaro Reinoso]

Yes, I've done that. I doesn't work either.

for chan in channels:
if chan.id == channel.id:
chan = session.merge(channel)
break

On Sep 13, 2:27 pm, Michael Bayer mike...@zzzcomputing.com wrote:
 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 mike...@zzzcomputing.com 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.

  --
  You received this message because you are subscribed to the Google Groups 
  sqlalchemy group.
  To post to this group, send email to sqlalch...@googlegroups.com.
  To unsubscribe from this group, send email to 
  sqlalchemy+unsubscr...@googlegroups.com.
  For more options, visit this group 
  athttp://groups.google.com/group/sqlalchemy?hl=en.

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Re: [sqlalchemy] Re: Updating a detached object

[Michael Bayer]

On Sep 13, 2010, at 2:31 PM, Alvaro Reinoso wrote:

 Yes, I've done that. I doesn't work either.
 
   for chan in channels:
   if chan.id == channel.id:
   chan = session.merge(channel)
   break

i dont understand the context of that code (what's channel) ?

This is how a basic merge works:

def merge_new_data(some_xml):
 my_objects = parse_xml(some_xml)

   # at this point, every object in my_objects should
   # have a primary key, as well as every child of every element,
   # all the way down.   Existing primary keys must be fully populated,
   # that's your job.  This is the intricate part, obviously.  But you don't 
   # merge anything here, just get the PKs filled in.

   # then you merge the whole thing.   merge() cascades along all 
   # relationships.   The rule is simple - if PK is present and exists in the 
DB, it 
   # updates.  otherwise, it inserts.

   for obj in my_objects:
   Session.merge(obj)
   Session.commit()

  # done






 
 On Sep 13, 2:27 pm, Michael Bayer mike...@zzzcomputing.com wrote:
 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 mike...@zzzcomputing.com 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