[sqlalchemy] proxied attribute access
g'day i need to have an attribute with setter/getter, say foo, and so that the underlaying DB/SA-attribute (_foo) to be completely hidden for users of the class - to avoid someone setting/getting it by mistake. is this possible within SA - via new AttributeAccess layer - or else? ciao svil --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SqlAlchemy and Stored Procedures with variables
Rick, On May 19, 4:30 pm, Rick Morrison [EMAIL PROTECTED] wrote: Does the same statement work in an interactive query window, complete with the embedded semicolon you're using? Also, you should be able to use positional parameters instead of named parameters in your call: cur.execute(execute stored_proc 'gra%' ) Note that as of yet there is no SQLAlchemy support for OUT or IN/OUT parameters; currently you can return a single set of results via a SELECT in the stored procedure. Rick The SQL works in our SQL analyzer with or without the named parameter and with the semicolon. We tried it the way you mentioned too, using positional parameters, and got the same error. I apologize for forgetting to mention that in my first post. Any other ideas? I'll look into the OUT parameter that Bayer mentions in his post. Mike --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] existing database/hibernating
Hello Alchemystas,
I have a legacy database, with a self written ORM not to fuss about.
So I want to use a some more intelligent mechanism - sqlalchemy.
I have written a little hibernator, that does nothing more, as to
ask the database for its metadata via sqlalchemy (heron:0.4.2p3-1)
and construct classes of the form:
from sqlalchemy import *
from sqlalchemy.orm import mapper
from dvzrv.db import sAmetaData
class SrvDomainTable(object):
def __init__(self,domain_name=None,srv_id=None):
self.sAtablename = 'srv_domain'
self.sAsrv_domain_table = Table(self.sAtablename, sAmetaData,
autoload=True)
self.sAmapped_srv_domain =
mapper(DVZsrvDomainTable,self.sAsrv_domain_table,primary_key=[self.sAsrv_domain_table.c.domain_name])
self.domain_name = domain_name
self.srv_id = srv_id
I still do not have clue, how to cope with association tables.
The class SrvDomainTable for example is one of those.
The usage of primary key is only to test functionality.
So my question is, will it suffice to use the primary key list
listing all foreign keys -like this:
primary_key=[self.sAsrv_domain_table.c.domain_name,self.sAsrv_domain_table.c.srv_id].
Or do I have to use it like the example in
http://www.sqlalchemy.org/docs/04/mappers.html ?
Regrettably I do not grasp the idea of the example up to now,
left_table = Table('left', metadata,
Column('id', Integer, primary_key=True))
right_table = Table('right', metadata,
Column('id', Integer, primary_key=True))
association_table = Table('association', metadata,
Column('left_id', Integer, ForeignKey('left.id')),
Column('right_id', Integer, ForeignKey('right.id')),
)
mapper(Parent, left_table, properties={
'children':relation(Child, secondary=association_table)
})
mapper(Child, right_table)
because it uses only the parent mapper to some things,
whereas the childmapper is unchanged..
thanks
gregor
--
Gregor Kling
Abteilung ITS, Sachgebiet DVZ
Fachhochschule Giessen
Tel: 0641/309-1292
E-Mail: [EMAIL PROTECTED]
smime.p7s
Description: S/MIME Cryptographic Signature
[sqlalchemy] Re: existing database/hibernating
On May 20, 2008, at 10:56 AM, Gregor Kling wrote:
Hello Alchemystas,
I have a legacy database, with a self written ORM not to fuss about.
So I want to use a some more intelligent mechanism - sqlalchemy.
I have written a little hibernator, that does nothing more, as to
ask the database for its metadata via sqlalchemy (heron:0.4.2p3-1)
and construct classes of the form:
from sqlalchemy import *
from sqlalchemy.orm import mapper
from dvzrv.db import sAmetaData
class SrvDomainTable(object):
def __init__(self,domain_name=None,srv_id=None):
self.sAtablename = 'srv_domain'
self.sAsrv_domain_table = Table(self.sAtablename, sAmetaData,
autoload=True)
self.sAmapped_srv_domain =
mapper
(DVZsrvDomainTable
,self
.sAsrv_domain_table
,primary_key=[self.sAsrv_domain_table.c.domain_name])
its not going to work if you create the mapper() (and Table) per class
instance (i.e. within __init__), although its not clear to me above
what you're actually doing since I do not know what
DVZsrvDomainTable is, or what its desired relationship is to
SrvDomainTable. It *looks* like the wrong pattern if in fact an
instance of a SrvDomainTable corresponds to a DVZsrvDomainTable
instance. If not, and SrvDomainTable is just created once at the
configurational level, its still a really hard-to-understand way of
doing things :). You might want to look into the declarative
extension which provides a simple pattern for defining classes,
mappers, and tables all at once (and if declarative doesn't work for
you, read the source code to it at least to see a fairly sane way of
doing things).
I still do not have clue, how to cope with association tables.
The class SrvDomainTable for example is one of those.
The usage of primary key is only to test functionality.
So my question is, will it suffice to use the primary key list
listing all foreign keys -like this:
primary_key
=
[self
.sAsrv_domain_table.c.domain_name,self.sAsrv_domain_table.c.srv_id].
assuming you are creating a Mapper to an association table, yes its
typical that the FK columns which connect the two target classes
formulate the primary key for the purposes of mapping (i.e. it
uniquely identifies the row).
left_table = Table('left', metadata,
Column('id', Integer, primary_key=True))
right_table = Table('right', metadata,
Column('id', Integer, primary_key=True))
association_table = Table('association', metadata,
Column('left_id', Integer, ForeignKey('left.id')),
Column('right_id', Integer, ForeignKey('right.id')),
)
mapper(Parent, left_table, properties={
'children':relation(Child, secondary=association_table)
})
mapper(Child, right_table)
this is not what SQLA refers to as an association mapping, this is
just a many-to-many which is somethign different. So im not sure
which pattern you're trying to use. The one with the primary keys on
the mapper is the association object at
http://www.sqlalchemy.org/docs/04/mappers.html#advdatamapping_relation_patterns_association
.
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[sqlalchemy] Re: SqlAlchemy and Stored Procedures with variables
On May 20, 10:13 am, Rick Morrison [EMAIL PROTECTED] wrote: The SQL works in our SQL analyzer with or without the named parameter and with the semicolon. We tried it the way you mentioned too, using positional parameters, and got the same error. I apologize for forgetting to mention that in my first post. Then perhaps you're not connected to the correct database, or it's a permissions issue? The way you're using the DB connection directly, SQLAlchemy is not issuing any SQL of it's own: it's a straight pass-through. I don't think it's a permissions thing...see below... Positional parameters work with pymssql, so I assume you're using pyodbc, correct? I haven't tried calling a stored procedure using pyodbc, anybody on the list have that working? I think we're using pymssql from a Linux box. Is there a way to tell which Python module SQLAlchemy is using? We tried running it with straight pymssql instead and it works in there: code import pymssql db = pymssql.connect(host=ntsql.ourSite.com,user=user,password=pw,database=ourDB) cur = db.cursor() cur.execute(execute sp_EDEN_Vendors @query='gra%';) print cur.fetchall() /code Any other ideas? I'll look into the OUT parameter that Bayer mentions in his post. Well if IN parameters don't work, OUT parameters probably aren't going to work either. If you're using pyodbc, I would try bringing the issue up on the pyodbc list. You're pretty much using the DB-API cursor directly, so it's not interference from SQLA. Crumb. Thanks. Mike --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SqlAlchemy and Stored Procedures with variables
Hi, The SQL works in our SQL analyzer with or without the named parameter and with the semicolon. We tried it the way you mentioned too, using positional parameters, and got the same error. I apologize for forgetting to mention that in my first post. Dunno if this is related, but pyodbc and adodbapi execute each statement in a separate context. This caused a problem with scope_identity, as in the original implementation with pyodbc, scope_identity always returned null. Paul --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Access to AS/400 data
On Fri, May 16, 2008 at 3:18 PM, Carlos Hanson [EMAIL PROTECTED] wrote: On Fri, May 16, 2008 at 10:49 AM, Jim Steil [EMAIL PROTECTED] wrote: Carlos Hanson wrote: On Fri, May 16, 2008 at 8:14 AM, Michael Bayer [EMAIL PROTECTED] wrote: On May 16, 2008, at 10:55 AM, Carlos Hanson wrote: On Fri, May 16, 2008 at 6:13 AM, Jim Steil [EMAIL PROTECTED] wrote: Hi: Can anyone tell me if it is possible to access data on an AS/400 through SQLAlchemy? -Jim It's possible if you use db2 connect to make your connection to the iSeries. See http://code.google.com/p/ibm-db/. The support group is [EMAIL PROTECTED] Right now, the as/400 is listed as a Future supported database [1], but there have been some reports from people getting it working. You might want to make your needs known on the support list also follow up with your IBM rep. [1] http://code.google.com/p/ibm-db/wiki/README I'm connecting to an AS/400 using pyodbc, so I am sure that I can do it through SQLAlchemy. If I have a chances to test it, I'll post my success. But if you get an ODBC connection set up, the re should be no problem. well, connecting is just the beginning. to take advantage of SQLA, you would also want an AS/400 dialect that knows how to render SQL in the way an AS/400 likes. Im not familiar with anyone working on an AS/ 400 dialect at the moment. I only know of the DB2 dialect which is a separate project (but maybe ask on their list since they work for IBM). This is a good point. I have to create aliases to a file/member combination to select data. I guess I wouldn't expect SQLAlchemy to implement that by default, since most every other database uses tables. Right... but there's no reason you can't drop down to the db-api level for one-off things like partitioning data with members. Once the alias is created, it can be treated like any other table. -ken --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SqlAlchemy and Stored Procedures with variables
I think we're using pymssql from a Linux box. Is there a way to tell which Python module SQLAlchemy is using? We tried running it with straight pymssql instead and it works in there: The MSSQL module does an auto-detect of the supported DB-API modules and uses the first one that imports without error. The sequence for the 0.4 series is [pyodbc, pymssql, adodbapi]. You can force module selection by using a 'module=' keyword argument to the create_engine call. Crumb. Thanks. Here's another: http://rcrumb.com/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SqlAlchemy and Stored Procedures with variables
We should really be using the ODBC sanctioned syntax for procedure call, which is still unsupported by pyodbc, AFAIK. ODBC on *nix is over 10 years old at this point, you'd think we'd have a better story to tell by now, jeez. Dunno if this is related, but pyodbc and adodbapi execute each statement in a separate context. This caused a problem with scope_identity, as in the original implementation with pyodbc, scope_identity always returned null. I thought the original impetus for scope_identity was not multiple execution contexts, but rather things being fouled up for some users where they had nested INSERTs being done via a trigger on the mapped table, and the brain-dead SELECT @@identity_insert wasn't able to pluck out the correct PK. Was there another reason I'm missing? Jason, how are coming on the dialect refactor? Things are heating up out here --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: proxied attribute access
[EMAIL PROTECTED] wrote: g'day i need to have an attribute with setter/getter, say foo, and so that the underlaying DB/SA-attribute (_foo) to be completely hidden for users of the class - to avoid someone setting/getting it by mistake. is this possible within SA - via new AttributeAccess layer - or else? Yep. There are examples in examples/custom_attributes plus more in test/orm/extendedattr.py and test/orm/instrumentation.py. Also doc in sqlalchemy.orm.attributes. (You'll need to consult the source on that one until we get a doc generator that can extract attribute docstrings.) --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] 64-bit postgres produces: This SchemaItem is not connected to any Engine
Hi there, I am building a zope/plone site that uses sqlalchemy (collective.lead). on two systems I am developping on everything works fine, a third one that has 64 bit linux installed (all systems use SuSE 10.3) I get an traceback: Module ruagaero.intradevcontent.db.db, line 22, in _setup_tables Module sqlalchemy.schema, line 166, in __call__ Module sqlalchemy.schema, line 70, in get_engine InvalidRequestError: This SchemaItem is not connected to any Engine how can I fix that? thanks for your help robert --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: existing database/hibernating
Michael Bayer wrote: from sqlalchemy import * from sqlalchemy.orm import mapper from dvzrv.db import sAmetaData class SrvDomainTable(object): def __init__(self,domain_name=None,srv_id=None): self.sAtablename = 'srv_domain' self.sAsrv_domain_table = Table(self.sAtablename, sAmetaData,autoload=True) self.sAmapped_srv_domain = mapper(SrvDomainTable,self.sAsrv_domain_table,primary_key=[self.sAsrv_domain_table.c.domain_name]) its not going to work if you create the mapper() (and Table) per class instance (i.e. within __init__), It was a typo. It should be all SrvDomainTable. But why shouldn't it work, I already do the test and it does. Could you please be more specific about this ? [self.sAsrv_domain_table.c.domain_name,self.sAsrv_domain_table.c.srv_id]. assuming you are creating a Mapper to an association table, yes its typical that the FK columns which connect the two target classes formulate the primary key for the purposes of mapping (i.e. it uniquely identifies the row). So this is the intended way to map a table which only connects to tables with the usage of FKs ? this is not what SQLA refers to as an association mapping, this is just a many-to-many which is somethign different. It could be that I misunderstand the intention of SA in relation to association mapping. What I want, is to map the association table (the table which connects two tables, that has only 2 keys - the foreign keys) to an object the same as i do with the rest of the tables; which all have nomrally an *explicit* pk. As I run into an error in relation of a missing pk, I tried to cope with that.In addition I found some post (anywhere), which handled this with adding this primary_key=[]-thing for those classes. So because I have not used SA before, there might be some gaps of understanding ;-) greetings gregor --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: (scoped_session.)commit() not doing anything
Finally solved the problem. It was caused by the incorrect way I used Session -- Previously the _q object is central initialized and shared, problem went away after I create per object instance. Jerry On May 19, 11:00 pm, jerryji [EMAIL PROTECTED] wrote: Hi, This commit()-not-doing-anything problem is driving me crazy :( All my other commits in the same code base are working perfectly, it's just this one. My Session is a scoped_session -- Session = scoped_session( sessionmaker(autoflush=True, transactional=True, ...)) A debug goes -- (Pdb) list 277 import pdb; pdb.set_trace() 278 - item_property = itemproperty_q.filter_by( 279 a_itemid=a_itemid, b_itemid=b_itemid, 280 propertyid=propertyid, 281 userid=userid).first() 282 item_property.fav_itemid = fav_itemid 283 model.Session.commit() (Pdb) n /item.py(279)compare() - a_itemid=a_itemid, b_itemid=b_itemid, (Pdb) n /item.py(280)compare() - propertyid=propertyid, (Pdb) n /item.py(281)compare() - userid=userid).first() (Pdb) n So far so good, generates lots of output from the select statement. The next statement sets item_property.fav_itemid to 10002 from None -- /item.py(282)compare() - item_property.fav_itemid = fav_itemid (Pdb) list 277 import pdb; pdb.set_trace() 278 item_property = itemproperty_q.filter_by( 279 a_itemid=a_itemid, b_itemid=b_itemid, 280 propertyid=propertyid, 281 userid=userid).first() 282 - item_property.fav_itemid = fav_itemid 283 model.Session.commit() (Pdb) item_property.fav_itemid (Pdb) fav_itemid 10002 But then the next Session.commit() statement does _nothing_ -- (Pdb) n /item.py(283)compare() - model.Session.commit() (Pdb) item_property.fav_itemid 10002 (Pdb) n /item.py(254)compare() I spent much time ripping the mapped table into an IPython session and saw it working fine -- In [82]: item_property.fav_itemid = 10002 In [83]: Session.commit() ...executes the update statement What could have gong wrong? _Many_ thanks in advance! Jerry --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: 64-bit postgres produces: This SchemaItem is not connected to any Engine
robert rottermann wrote: Hi there, I am building a zope/plone site that uses sqlalchemy (collective.lead). on two systems I am developping on everything works fine, a third one that has 64 bit linux installed (all systems use SuSE 10.3) I get an traceback: Module ruagaero.intradevcontent.db.db, line 22, in _setup_tables Module sqlalchemy.schema, line 166, in __call__ Module sqlalchemy.schema, line 70, in get_engine InvalidRequestError: This SchemaItem is not connected to any Engine 0.3.x? could be an attempt in '_setup_tables' to autoload tables without a database configured to load from. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: existing database/hibernating
On May 20, 2008, at 12:15 PM, Gregor Kling wrote: its not going to work if you create the mapper() (and Table) per class instance (i.e. within __init__), It was a typo. It should be all SrvDomainTable. But why shouldn't it work, I already do the test and it does. Could you please be more specific about this ? the mapper links itself to the class. additionally, the mapper compiles itself and places instrumentation upon the class that receives events and tracks history. Its not valid to create another primary mapper for the same class without explcitily removing the first one - it will raise an error. There's a lot of dependencies set up at the class level, and things would break very badly if they were re-created uniquely on different instances of the same class. Primary mapper construction is also a fairly expensive process in comparison with whats appropriate for object instantiation. [self .sAsrv_domain_table.c.domain_name,self.sAsrv_domain_table.c.srv_id]. assuming you are creating a Mapper to an association table, yes its typical that the FK columns which connect the two target classes formulate the primary key for the purposes of mapping (i.e. it uniquely identifies the row). So this is the intended way to map a table which only connects to tables with the usage of FKs ? its typical since the set of foreign keys defines uniqueness for the row. We are looking here for a natural primary key, which you can see defined at http://en.wikipedia.org/wiki/Primary_key . But from what you've mentioned below, you aren't actually mapping to the association table, it's used only within a many-to-many relation(). So the explicit specification of primary key doesn't apply in that case. this is not what SQLA refers to as an association mapping, this is just a many-to-many which is somethign different. It could be that I misunderstand the intention of SA in relation to association mapping. What I want, is to map the association table (the table which connects two tables, that has only 2 keys - the foreign keys) to an object the same as i do with the rest of the tables; which all have nomrally an *explicit* pk. this is a plain many-to-many relation. The example in the docs for many-to-many applies, and no mapper for this specific table is needed; its sent along as secondary to a relation(). As I run into an error in relation of a missing pk, I tried to cope with that.In addition I found some post (anywhere), which handled this with adding this primary_key=[]-thing for those classes. So because I have not used SA before, there might be some gaps of understanding ;-) since theres no mapper needed for the secondary table, no primary key argument is specified either. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: 64-bit postgres produces: This SchemaItem is not connected to any Engine
thanks jason, jason kirtland schrieb: robert rottermann wrote: Hi there, I am building a zope/plone site that uses sqlalchemy (collective.lead). on two systems I am developping on everything works fine, a third one that has 64 bit linux installed (all systems use SuSE 10.3) I get an traceback: Module ruagaero.intradevcontent.db.db, line 22, in _setup_tables Module sqlalchemy.schema, line 166, in __call__ Module sqlalchemy.schema, line 70, in get_engine InvalidRequestError: This SchemaItem is not connected to any Engine 0.3.x? could be an attempt in '_setup_tables' to autoload tables without a database configured to load from. I am usin 0.4.6 the same confuguration works on 32 bit linux robert --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: 64-bit postgres produces: This SchemaItem is not connected to any Engine
robert rottermann wrote: thanks jason, jason kirtland schrieb: robert rottermann wrote: Hi there, I am building a zope/plone site that uses sqlalchemy (collective.lead). on two systems I am developping on everything works fine, a third one that has 64 bit linux installed (all systems use SuSE 10.3) I get an traceback: Module ruagaero.intradevcontent.db.db, line 22, in _setup_tables Module sqlalchemy.schema, line 166, in __call__ Module sqlalchemy.schema, line 70, in get_engine InvalidRequestError: This SchemaItem is not connected to any Engine 0.3.x? could be an attempt in '_setup_tables' to autoload tables without a database configured to load from. I am usin 0.4.6 the same confuguration works on 32 bit linux The get_engine function in that traceback don't exist in the 0.4 series. Is it possible you're picking up another (maybe system) SA installation instead of 0.4.6? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] mapper extension
I am looking for a hook after a instance has been created, attribute populated and any initialization done. I have found populate_instance in the MapperExtension. It look like to close thing. Adding a hook to MapperExtension for after instance is created, populated, and any initialization by the orm be great. I am assuming that that lazy loading go thought this interface also. Is there any public api to handle the populating of the attributes and do any initialization that might happen when I return EXT_STOP ? The idea would be to do the work of populate_instance and let my framework do the initialization it needs. The goal is to have a chance to do more initialization for my framework after sqlachemy has load any instance from the orm. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] ShardedSession and id_chooser
Some of my tables (in a web application using Pylons) will eventually need to be partitioned to separate shards, but some tables won't. For example, imagine that I'd like to partition a Users table across 3 different databases, while leaving others just on one master database. I've read the ShardedSession docs a few times. The shard_chooser() callable is straightforward, and thanks to the example [1], I think I understand how to use query_chooser(); but I need a pointer about how to use id_chooser() properly. The docs describe id_chooser as this: a function which can return a list of shard ids which apply to a particular instance identifier, but that seems unclear to me. Say I issue the following queries: 1) Session.query(User).filter_by(id=4) 2) Session.query(UnrelatedTable).filter_by(id=567) 3) Session.query(UserProfiles).filter_by(user_id=4) # where UserProfiles is mapped to a User class In the first query, the id_chooser would simply return the proper shard, since I know that I'm querying for a User. The second query searches for a completely unrelated (non-sharded) table; how would I inspect the id_chooser()'s query parameter to determine that it's searching for a user? Lastly, in the third query above, which only indirectly wants to find a User class, which shard callable would be invoked and how do I make sure it finds the right shard for the associated User? A related question: Should I use a separate Session to separate the sharded tables from the non-sharded ones, in the case where I would not need to aggregate queries between the two sessions? If I were doing this in plain SQL, I'd probably just connect to all of the databases, and then manually choose which instance to perform individual queries on (query aggregation between shards doesn't need to happen much in my current project). Apologies in advance if my questions are confusing; I'm having trouble grasping whether it's feasible to use the ORM for this or if it would be simpler/clearer to take a more manual approach. [1]: http://www.sqlalchemy.org/trac/browser/sqlalchemy/trunk/examples/sharding/attribute_shard.py --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] in not implemented for queries?
Hi, Just wanted to check: I am seeing a NotImplementedError (v 0.4.6 on Linux w Python 2.5) when I try to query some objects with the filter in. Does that mean that the feature is not implemented, or is it more likely an error in my code (eg somehow I'm calling a base class; Address.email_address.in_ does appear in the ORM tutorial, which makes me wonder whether it is supported)? If this is unsupported, what's the best approach? Just loop over the various instances myself? My code looks like: query = session.query(Measurement) query = query.filter(Measurement.time_series.in_(time_series)) where Measurement is a mapped class, and time_series is both a list of TimeSeries instances (another mapped class) and a Measurement attribute that is mapped via a relation. If it's relevant - Measurement is actually a base class for joined table inheritance (the time series key col is in the base class table). The trace looks like: File /home/andrew/projects/isti/kpi-pilot-2/repository-tool/src/ isti/reptool/core/actions/readonly.py, line 96, in _no_undo Measurement.time_series.in_(time_series)) File /usr/lib64/python2.5/site-packages/sqlalchemy/sql/ expression.py, line 1220, in in_ return self.operate(operators.in_op, other) File /usr/lib64/python2.5/site-packages/sqlalchemy/orm/ attributes.py, line 56, in operate return op(self.comparator, *other, **kwargs) File /usr/lib64/python2.5/site-packages/sqlalchemy/sql/ operators.py, line 47, in in_op return a.in_(*b) File /usr/lib64/python2.5/site-packages/sqlalchemy/sql/ expression.py, line 1220, in in_ return self.operate(operators.in_op, other) File /usr/lib64/python2.5/site-packages/sqlalchemy/sql/ expression.py, line 1181, in operate raise NotImplementedError() NotImplementedError Finally, thanks for this library - it's an excellent piece of software. The first ORM/SQL lib that I've felt really works well. Cheers, Andrew --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
