[sqlalchemy] Re: Managing transactions from Session using raw_connections
Hi Michael, thanks for your help. Since some of my engines are not bound to mappers I've tried the approach suggested in your previous post to subclass Session so that 'get_bind' would accept an additional 'engine' argument. This works fine with Session.execute() which passes **kw down to the 'get_bind' method, but unfortunately Session.connection() doesn't. Is this omitted intentionally, or could it be added? Thanks a lot, Ralph Here you'd use Session.execute() and Session.connection() to get at the Connection you'd normally get from engine.contextual_connect() (http://www.sqlalchemy.org/docs/orm/session.html#using-sql-expressions...) . execute() and connection() accept a mapper argument for the case where individual engines are associated with individual mappers, and both ultimately call get_bind() which you can override via subclass if desired to accept other kinds of arguments. -- 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.
[sqlalchemy] Re: Trouble detaching all objects with relationships intact
On Dec 6, 5:53 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 6, 2010, at 11:52 AM, Ian Thompson wrote: On Dec 6, 4:49 pm, Ian Thompson quorn...@gmail.com wrote: I've generated a test data set and then want to have all of the created objects and relationships available for reference easily. To avoid possible pollution of this fixture I want to detach the objects from the sessions to avoid them getting any updates applied. To do this I am attempting to load all data via joinedload and then calling session.expunge_all: print assets['test_asset_1'].attributes # OK session.query(Asset).options(joinedload(Asset.asset_attributes)).populate_e xisting().all() session.expunge_all() print assets['test_asset_1'].attributes # ERROR None of the relationships on the objects survive the expunge. sqlalchemy.orm.exc.DetachedInstanceError: Parent instance Asset at ... is not bound to a Session; lazy load operation of attribute 'asset_attributes' cannot proceed (cont...) Is there a correct way to detach all current data from the Session fully loading any relationships? (Small data set so memory is not a concern.) This use case seems like it would be more easily solved using a new Session just for that load. To work with the objects detached, all deferred attributes and lazy-loading relationship attributes which you will need to access would need to either be eagerly loaded (there's now three ways to eagerly load relationship() attributes), or otherwise accessed via obj.attribute before the objects are expunged. Hi Michael, thanks for your reply. I had thought by using joinedload (or eagerload) and populate_existing I would be doing an eager load of the specified relation. Also, in my example I do access the attributes relationship (with a print), then after the expunge the same fails. Is there a way I can ensure the data is preserved after expunging? Thanks Ian -- 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.
[sqlalchemy] Re: Problem with one relation
The relation is OK, one-to-many between Playlist and PlaylisItem. However, PlaylistItem can contain one Playlist or one Layout and that Playlist could be in many PlaylistItems. I know it's weird relation if I already have Playlist as parent of PlaylistItem, but could I get this? Thanks! On Dec 6, 3:51 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 6, 2010, at 2:39 PM, Alvaro Reinoso wrote: Hi all, I have those two classes: class Playlist(rdb.Model): Represents playlist. It may contain playlist items rdb.metadata(metadata) rdb.tablename(playlists) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) pending = Column(pending, Boolean) items = relationship(PlaylistItem, cascade=all, delete, backref=playlists) screens = relationship(Screen, secondary=playlist_screens, backref=playlists) class PlaylistItem(rdb.Model): Represents a playlist of items in Schedule page rdb.metadata(metadata) rdb.tablename(playlist_items) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) runtime = Column(runtime, Integer) layoutId = Column(layout_id, Integer, ForeignKey(layouts.id)) playlistId = Column(playlist_id, Integer, ForeignKey(playlists.id)) layout = relationship(Layout, uselist=False) playlist = relationship(Playlist, uselist=False) One playlist can contain many PlaylistItem and PlaylistItem could contain layout or another playlist. The problem is when adding a PlaylistItem to a Playlist, PlaylistItem automatically gets the id of its parent (playlist_id). How can I avoid this? Thanks in advance! the items collection of Playlist represents a one-to-many reference to a list of PlaylistItems. A PlaylistItem in turn can only be referenced by one parent. The items/playlists relationships therefore manage the playlistId attribute to be the one foreign key represented by this ownership. If a PlaylistItem is capable of having multiple Playlist parents, this relationship should be changed to a many-to-many. Reference on relationship() patterns is athttp://www.sqlalchemy.org/docs/orm/relationships.html#basic-relationa -- 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. -- 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.
Re: [sqlalchemy] Re: Managing transactions from Session using raw_connections
when I answered your email I realized we should probably add a bind argument to connection() and execute(), for those cases where you have the actual bind (and the kw, for subclass situations). ticket #1996 On Dec 7, 2010, at 7:32 AM, Ralph Heinkel wrote: Hi Michael, thanks for your help. Since some of my engines are not bound to mappers I've tried the approach suggested in your previous post to subclass Session so that 'get_bind' would accept an additional 'engine' argument. This works fine with Session.execute() which passes **kw down to the 'get_bind' method, but unfortunately Session.connection() doesn't. Is this omitted intentionally, or could it be added? Thanks a lot, Ralph Here you'd use Session.execute() and Session.connection() to get at the Connection you'd normally get from engine.contextual_connect() (http://www.sqlalchemy.org/docs/orm/session.html#using-sql-expressions...) . execute() and connection() accept a mapper argument for the case where individual engines are associated with individual mappers, and both ultimately call get_bind() which you can override via subclass if desired to accept other kinds of arguments. -- 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. -- 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.
Re: [sqlalchemy] Re: Trouble detaching all objects with relationships intact
On Dec 7, 2010, at 7:46 AM, Ian Thompson wrote: On Dec 6, 5:53 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 6, 2010, at 11:52 AM, Ian Thompson wrote: On Dec 6, 4:49 pm, Ian Thompson quorn...@gmail.com wrote: I've generated a test data set and then want to have all of the created objects and relationships available for reference easily. To avoid possible pollution of this fixture I want to detach the objects from the sessions to avoid them getting any updates applied. To do this I am attempting to load all data via joinedload and then calling session.expunge_all: print assets['test_asset_1'].attributes # OK session.query(Asset).options(joinedload(Asset.asset_attributes)).populate_e xisting().all() session.expunge_all() print assets['test_asset_1'].attributes # ERROR None of the relationships on the objects survive the expunge. sqlalchemy.orm.exc.DetachedInstanceError: Parent instance Asset at ... is not bound to a Session; lazy load operation of attribute 'asset_attributes' cannot proceed (cont...) Is there a correct way to detach all current data from the Session fully loading any relationships? (Small data set so memory is not a concern.) This use case seems like it would be more easily solved using a new Session just for that load. To work with the objects detached, all deferred attributes and lazy-loading relationship attributes which you will need to access would need to either be eagerly loaded (there's now three ways to eagerly load relationship() attributes), or otherwise accessed via obj.attribute before the objects are expunged. Hi Michael, thanks for your reply. I had thought by using joinedload (or eagerload) and populate_existing I would be doing an eager load of the specified relation. Also, in my example I do access the attributes relationship (with a print), then after the expunge the same fails. Is there a way I can ensure the data is preserved after expunging? expunge() doesn't affect the data associated with the instances. Its possible the populate_existing() is interfering with the joined load, I'd check the status of asset_attributes right after the query. Thanks Ian -- 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. -- 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.
Re: [sqlalchemy] Re: Problem with one relation
On Dec 7, 2010, at 10:09 AM, Alvaro Reinoso wrote: The relation is OK, one-to-many between Playlist and PlaylisItem. However, PlaylistItem can contain one Playlist or one Layout and that Playlist could be in many PlaylistItems. I know it's weird relation if I already have Playlist as parent of PlaylistItem, but could I get this? If you mean, you want PlaylistItem.playlist to be independent of Playlist.items, just use two different foreign keys and two different relationships. Otherwise I don't really have enough detail here to know what you're asking for. Thanks! On Dec 6, 3:51 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 6, 2010, at 2:39 PM, Alvaro Reinoso wrote: Hi all, I have those two classes: class Playlist(rdb.Model): Represents playlist. It may contain playlist items rdb.metadata(metadata) rdb.tablename(playlists) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) pending = Column(pending, Boolean) items = relationship(PlaylistItem, cascade=all, delete, backref=playlists) screens = relationship(Screen, secondary=playlist_screens, backref=playlists) class PlaylistItem(rdb.Model): Represents a playlist of items in Schedule page rdb.metadata(metadata) rdb.tablename(playlist_items) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) runtime = Column(runtime, Integer) layoutId = Column(layout_id, Integer, ForeignKey(layouts.id)) playlistId = Column(playlist_id, Integer, ForeignKey(playlists.id)) layout = relationship(Layout, uselist=False) playlist = relationship(Playlist, uselist=False) One playlist can contain many PlaylistItem and PlaylistItem could contain layout or another playlist. The problem is when adding a PlaylistItem to a Playlist, PlaylistItem automatically gets the id of its parent (playlist_id). How can I avoid this? Thanks in advance! the items collection of Playlist represents a one-to-many reference to a list of PlaylistItems. A PlaylistItem in turn can only be referenced by one parent. The items/playlists relationships therefore manage the playlistId attribute to be the one foreign key represented by this ownership.If a PlaylistItem is capable of having multiple Playlist parents, this relationship should be changed to a many-to-many.Reference on relationship() patterns is athttp://www.sqlalchemy.org/docs/orm/relationships.html#basic-relationa -- 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. -- 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. -- 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.
[sqlalchemy] table inheritance
Hey,
I have a declarative table called 'Foo':
_Base = declarative_base()
class Foo(_Base):
__tablename__ = 'foo'
__table_args__ = {'mysql_engine': 'InnoDB',
'mysql_charset': 'latin1'}
id = Column(String(64), primary_key=True, autoincrement=False)
stuff = Column(Integer(11), primary_key=True, nullable=False)
Now I create Foo1 that has exactly the same definition but differs
just by the name:
class Foo1(_Base):
__tablename__ = 'foo1'
__table_args__ = {'mysql_engine': 'InnoDB',
'mysql_charset': 'latin1'}
id = Column(String(64), primary_key=True, autoincrement=False)
stuff = Column(Integer(11), primary_key=True, nullable=False)
And I need more of those (FooN with N = 10). The use case is to shard
data across several tables.
To avoid cut/n/pastes, I tried inheritance, meta-class, a type
factory and the like, but everything fails. Whether because I was
reusing the same column class objects or whether because I was
conflicting with SQLALchemy meta-class magic.
Is there any sane way to do this and avoid a crazy copy/paste ?
Cheers
Tarek
--
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Re: [sqlalchemy] table inheritance
This is the entity name recipe, and we have a classical and declarative
version over at http://www.sqlalchemy.org/trac/wiki/UsageRecipes/EntityName .
It's using just the straight type() factory.
You definitely want to use distinct Column objects for each class, this because
a Column object is immediately made to reference its parent Table, for obvious
reasons. Recipes that generate multiple tables from a single set of Column
objects use the copy() method on Column for this purpose. However, you don't
even need to deal with that, since declarative mixins take care of the copy()
stuff for you. I've updated the EntityName example to illustrate taking
advantage of the mixin so check it out.
On Dec 7, 2010, at 10:45 AM, Tarek Ziadé wrote:
Hey,
I have a declarative table called 'Foo':
_Base = declarative_base()
class Foo(_Base):
__tablename__ = 'foo'
__table_args__ = {'mysql_engine': 'InnoDB',
'mysql_charset': 'latin1'}
id = Column(String(64), primary_key=True, autoincrement=False)
stuff = Column(Integer(11), primary_key=True, nullable=False)
Now I create Foo1 that has exactly the same definition but differs
just by the name:
class Foo1(_Base):
__tablename__ = 'foo1'
__table_args__ = {'mysql_engine': 'InnoDB',
'mysql_charset': 'latin1'}
id = Column(String(64), primary_key=True, autoincrement=False)
stuff = Column(Integer(11), primary_key=True, nullable=False)
And I need more of those (FooN with N = 10). The use case is to shard
data across several tables.
To avoid cut/n/pastes, I tried inheritance, meta-class, a type
factory and the like, but everything fails. Whether because I was
reusing the same column class objects or whether because I was
conflicting with SQLALchemy meta-class magic.
Is there any sane way to do this and avoid a crazy copy/paste ?
Cheers
Tarek
--
Tarek Ziadé | http://ziade.org
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Re: [sqlalchemy] table inheritance
On Tue, Dec 7, 2010 at 5:08 PM, Michael Bayer mike...@zzzcomputing.com wrote: This is the entity name recipe, and we have a classical and declarative version over at http://www.sqlalchemy.org/trac/wiki/UsageRecipes/EntityName . It's using just the straight type() factory. You definitely want to use distinct Column objects for each class, this because a Column object is immediately made to reference its parent Table, for obvious reasons. Recipes that generate multiple tables from a single set of Column objects use the copy() method on Column for this purpose. However, you don't even need to deal with that, since declarative mixins take care of the copy() stuff for you. I've updated the EntityName example to illustrate taking advantage of the mixin so check it out. Thanks ! I am always amazed by how fast and accurately you are always answering here, kudos for this. Cheers Tarek -- Tarek Ziadé | http://ziade.org -- 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.
Re: [sqlalchemy] Re: Managing transactions from Session using raw_connections
I hadn't planned any future 0.5 releases, 0.7 is almost ready for betas. What are the incompatibilities you have with 0.6 ? On Dec 7, 2010, at 11:58 AM, Ralph Heinkel wrote: This would be great! Thanks, Michael! (is this also going into the 0.5.x branch - we are not yet able to upgrade to 0.6.x due to incompatibilities...) Ralph On Dec 7, 4:09 pm, Michael Bayer mike...@zzzcomputing.com wrote: when I answered your email I realized we should probably add a bind argument to connection() and execute(), for those cases where you have the actual bind (and the kw, for subclass situations). ticket #1996 On Dec 7, 2010, at 7:32 AM, Ralph Heinkel wrote: Hi Michael, thanks for your help. Since some of my engines are not bound to mappers I've tried the approach suggested in your previous post to subclass Session so that 'get_bind' would accept an additional 'engine' argument. This works fine with Session.execute() which passes **kw down to the 'get_bind' method, but unfortunately Session.connection() doesn't. Is this omitted intentionally, or could it be added? Thanks a lot, Ralph Here you'd use Session.execute() and Session.connection() to get at the Connection you'd normally get from engine.contextual_connect() (http://www.sqlalchemy.org/docs/orm/session.html#using-sql-expressions...) .execute() and connection() accept a mapper argument for the case where individual engines are associated with individual mappers, and both ultimately call get_bind() which you can override via subclass if desired to accept other kinds of arguments. -- 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. -- 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. -- 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.
[sqlalchemy] composite property not working on a mapped select
Hello,
I've been trying to map two tables that have 25 columns each in
addition to
keys. The parent table's (descriptions) column values represent the
key in a
dictionary and the child table's (values) column values represent the
values of
the dictionary.
i.e.:
table 'descriptions':
id SERIAL
description1 Text
description2 Text
...
description25 Text
table 'values':
id SERIAL
descriptions_id INTEGER NOT NULL FOREIGN KEY descriptions.id
value1 Text
value2 Text
...
value25 Text
I wanted to map the join of the descriptions table and the values
table to a
single class and make two composite properties that would represent
the 50
columns.
Below I stared to do a prototype of this and ran into a problem with
composite
properties not working on mapped join (select alias). I never got
around to
making the dictionary I planned.
And I know that the design of the descriptions table and values table
is not
the best but it's what I have to work with at this point.
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, mapper, relationship,
composite
from sqlalchemy.schema import Table, Column, MetaData, ForeignKey
from sqlalchemy.sql import select
from sqlalchemy.types import Integer, Text
engine = create_engine('sqlite:///')
session = sessionmaker(bind=engine, autocommit=True)()
metadata = MetaData(engine)
# Tables
descriptions_table = Table('descriptions', metadata,
Column('id', Integer, primary_key=True),
Column('d1', Text),
Column('d2', Text),
)
values_table = Table('values', metadata,
Column('id', Integer, primary_key=True),
Column('description_id', Integer, ForeignKey('descriptions.id'),
nullable=False),
Column('v1', Text),
Column('v2', Text),
)
desc_values = select(
[values_table, descriptions_table.c.d1, descriptions_table.c.d2],
descriptions_table.c.id == values_table.c.description_id
).alias('descriptions_values')
# Classes
class Descriptions(object):
pass
class Values(object):
pass
class CustomValues(list):
def __init__(self, *args):
self.extend(args)
def __composite_values__(self):
return self
# Mappers
mapper(Descriptions, descriptions_table, properties={
'values': relationship(Values, lazy='dynamic'),
'custom_descriptions': composite(CustomValues,
descriptions_table.c.d1,
descriptions_table.c.d2),
})
mapper(Values, desc_values, properties={
'custom_descriptions': composite(CustomValues, desc_values.c.v1,
desc_values.c.v2),
})
# Testing
metadata.create_all()
engine.echo = True
descriptions = Descriptions()
descriptions.custom_descriptions = CustomValues('Color', 'Number')
values1 = Values()
values1.custom_values = CustomValues('Red', '5')
values2 = Values()
values2.custom_values = CustomValues('Blue', '1')
descriptions.values.append(values1)
descriptions.values.append(values2)
session.add(descriptions)
session.flush()
# Output
2010-12-07 13:32:04,933 INFO sqlalchemy.engine.base.Engine.0x...e690
BEGIN (implicit)
2010-12-07 13:32:04,933 INFO sqlalchemy.engine.base.Engine.0x...e690
INSERT INTO descriptions (d1, d2) VALUES (?, ?)
2010-12-07 13:32:04,933 INFO sqlalchemy.engine.base.Engine.0x...e690
('Color', 'Number')
2010-12-07 13:32:04,934 INFO sqlalchemy.engine.base.Engine.0x...e690
INSERT INTO values (description_id, v1, v2) VALUES (?, ?, ?)
2010-12-07 13:32:04,934 INFO sqlalchemy.engine.base.Engine.0x...e690
(1, None, None)
2010-12-07 13:32:04,934 INFO sqlalchemy.engine.base.Engine.0x...e690
INSERT INTO values (description_id, v1, v2) VALUES (?, ?, ?)
2010-12-07 13:32:04,935 INFO sqlalchemy.engine.base.Engine.0x...e690
(1, None, None)
2010-12-07 13:32:04,935 INFO sqlalchemy.engine.base.Engine.0x...e690
COMMIT
From this ouput we can see that v1 and v2 are not being set, they are
being
left at None, but descriptions.custom_descriptions IS being set
properly.
I'm hoping it's just something I missed.
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[sqlalchemy] Re: Problem with one relation
Yes, that's what I want. I already have the two relations that I want.: One is in Playlist, items = relationship(PlaylistItem, cascade=all, delete, backref=playlists). If I understand properly, this allows Playlist to contain PlaylistItems And the another one is in PlaylistItem, playlist = relationship(Playlist, uselist=False). This one is the one that allows the PlaylistItem to contain objects of Playlist type. (Or at least, that's what I'd like it to be). This shouldn't be pointing to its Playlist parent, but to a different Playlist (which this item contains, because a Playlist can contain other Playlists inside) I guess for that I'd need another ForeignKey(playlists.id), but I don't really know how to differentiate this ForeignKey from the one that is pointing to its parent Playlist object (or record). Thank you for your help, btw On Dec 7, 10:16 am, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 7, 2010, at 10:09 AM, Alvaro Reinoso wrote: The relation is OK, one-to-many between Playlist and PlaylisItem. However, PlaylistItem can contain one Playlist or one Layout and that Playlist could be in many PlaylistItems. I know it's weird relation if I already have Playlist as parent of PlaylistItem, but could I get this? If you mean, you want PlaylistItem.playlist to be independent of Playlist.items, just use two different foreign keys and two different relationships. Otherwise I don't really have enough detail here to know what you're asking for. Thanks! On Dec 6, 3:51 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Dec 6, 2010, at 2:39 PM, Alvaro Reinoso wrote: Hi all, I have those two classes: class Playlist(rdb.Model): Represents playlist. It may contain playlist items rdb.metadata(metadata) rdb.tablename(playlists) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) pending = Column(pending, Boolean) items = relationship(PlaylistItem, cascade=all, delete, backref=playlists) screens = relationship(Screen, secondary=playlist_screens, backref=playlists) class PlaylistItem(rdb.Model): Represents a playlist of items in Schedule page rdb.metadata(metadata) rdb.tablename(playlist_items) id = Column(id, Integer, primary_key=True) title = Column(title, String(50)) runtime = Column(runtime, Integer) layoutId = Column(layout_id, Integer, ForeignKey(layouts.id)) playlistId = Column(playlist_id, Integer, ForeignKey(playlists.id)) layout = relationship(Layout, uselist=False) playlist = relationship(Playlist, uselist=False) One playlist can contain many PlaylistItem and PlaylistItem could contain layout or another playlist. The problem is when adding a PlaylistItem to a Playlist, PlaylistItem automatically gets the id of its parent (playlist_id). How can I avoid this? Thanks in advance! the items collection of Playlist represents a one-to-many reference to a list of PlaylistItems. A PlaylistItem in turn can only be referenced by one parent. The items/playlists relationships therefore manage the playlistId attribute to be the one foreign key represented by this ownership. If a PlaylistItem is capable of having multiple Playlist parents, this relationship should be changed to a many-to-many. Reference on relationship() patterns is athttp://www.sqlalchemy.org/docs/orm/relationships.html#basic-relationa -- 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. -- 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. -- 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.
Re: [sqlalchemy] Failing test - SQLAlchemy 0.5.8, python 2.7.0
On Thursday, November 25, 2010 02:29 am, Michael Bayer wrote well I'd just take those tests out of 0.5 , I'm not sure if theres any other way to affect the outcome of nosetests without modifying SQLA code or tests directly. I finally had time to resolve this. Link to my patch (just for tracking purposes): http://pkgs.fedoraproject.org/gitweb/?p=python-sqlalchemy0.5.git;a=blob;f=python-sqlalchemy0.5- py27.patch;h=6946e846f1430bb9d7dc1137eea9afa8e7eb822e;hb=HEAD If anyone has less awkward solution, please let me know. Regards, Martin On Nov 24, 2010, at 8:17 PM, Martin Bacovsky wrote: On Thursday, November 25, 2010 01:41 am, Michael Bayer wrote there might be some dictionary ordering dependencies in those tests, which will not behave consistently across platforms. if they fail with 0.6.5 as well, let me know and we'll file a ticket. There aren't any 0.5 releases planned. Thanks for the quick response. With 0.6.5 I didn't noticed this issue, but I need to use 0.5.x because of some dependences. I suspect dictionary ordering too, but it seems to be somewhere in statement compiler which I don't feel like to touch ;). I'll rather try to add some workaround in the tests. Regards, Martin On Nov 24, 2010, at 7:06 PM, Martin Bacovsky wrote: Hi, I'm trying to build SqlAlchemy 0.5.8 (Linux, python 2.7.0). From time to time some of the tests fail. - the sources are always the same - so far the only affected tests were those testing compilation of statements with joined tables - the orderning of the tables in the from clause seems to be random - sometimes match the expected stmt sometimes not - it also seems that on different machines different tests tend to fail :O. Excerpt from buildlog showing the behaviour is attached. Does anyone have met this issue? Any idea how to deal with it? For the sake of completeness I add that there was also test failing on @profiling.function_call_count which I fixed by adding expected numbers for python 2.7. But I don't expect it is related. Regards, Martin nosetests ... .. .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... .. ... ...F.. ... . == FAIL: test.sql.test_select.SelectTest.test_binds -- Traceback (most recent call last): File /usr/lib/python2.7/site-packages/nose/case.py, line 186, in runTest self.test(*self.arg) File /builddir/build/BUILD/SQLAlchemy-0.5.8/lib/sqlalchemy/test/testing.py , line 368, in safe return fn(*args, **kw) File /builddir/build/BUILD/SQLAlchemy-0.5.8/test/sql/test_select.py, line 1193, in test_binds self.assert_compile(stmt, expected_named_stmt, params=expected_default_params_dict) File
Re: [sqlalchemy] composite property not working on a mapped select
its a bug, and theres a new ticket http://www.sqlalchemy.org/trac/ticket/1997
with a small patch.
I would suggest maybe not using composites for this for now. Most of what
composite does you can accomplish using descriptors:
class Value(object):
@property
def custom_values(self):
return CustomValue(self.v1, self.v2)
@custom_values.setter
def custom_values(self, value):
self.v1 = value.v1
self.v2 = value.v2
I considered replacing the mechanism of composite with the above type of thing
in 0.7 but there were still some edge cases that composites seem to have.
On Dec 7, 2010, at 1:54 PM, Will wrote:
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, mapper, relationship,
composite
from sqlalchemy.schema import Table, Column, MetaData, ForeignKey
from sqlalchemy.sql import select
from sqlalchemy.types import Integer, Text
engine = create_engine('sqlite:///')
session = sessionmaker(bind=engine, autocommit=True)()
metadata = MetaData(engine)
# Tables
descriptions_table = Table('descriptions', metadata,
Column('id', Integer, primary_key=True),
Column('d1', Text),
Column('d2', Text),
)
values_table = Table('values', metadata,
Column('id', Integer, primary_key=True),
Column('description_id', Integer, ForeignKey('descriptions.id'),
nullable=False),
Column('v1', Text),
Column('v2', Text),
)
desc_values = select(
[values_table, descriptions_table.c.d1, descriptions_table.c.d2],
descriptions_table.c.id == values_table.c.description_id
).alias('descriptions_values')
# Classes
class Descriptions(object):
pass
class Values(object):
pass
class CustomValues(list):
def __init__(self, *args):
self.extend(args)
def __composite_values__(self):
return self
# Mappers
mapper(Descriptions, descriptions_table, properties={
'values': relationship(Values, lazy='dynamic'),
'custom_descriptions': composite(CustomValues,
descriptions_table.c.d1,
descriptions_table.c.d2),
})
mapper(Values, desc_values, properties={
'custom_descriptions': composite(CustomValues, desc_values.c.v1,
desc_values.c.v2),
})
# Testing
metadata.create_all()
engine.echo = True
descriptions = Descriptions()
descriptions.custom_descriptions = CustomValues('Color', 'Number')
values1 = Values()
values1.custom_values = CustomValues('Red', '5')
values2 = Values()
values2.custom_values = CustomValues('Blue', '1')
descriptions.values.append(values1)
descriptions.values.append(values2)
session.add(descriptions)
session.flush()
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