[sqlalchemy] Re: How to get list of relations
Hi, You are missing a compile call before you can iterate properties. try adding: Ah, that is indeed the problem. With that in place, iterate_properties does very nearly what I need. The only problem is that I need to get the name of the relation as well. For now, the following works: [(a,b) for a,b in getattr(obj.mapper, '_Mapper__props').items() if isinstance(b, sqlalchemy.orm.properties.PropertyLoader)] There's probably a better way, but my app is now working. 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: How to get list of relations
Hei Wes and Paul...
On 10/29/07, Wes Duff [EMAIL PROTECTED] wrote:
Hey whats going on.
I am a new sqlalchemist as well but lets see if this helps any.
This is how I am getting a list of all names that corrispond with my
document names class.
names = [ c.name for c in model.Document.select_by(param=param) ]
So I am just collecting all the names from my Document table. I added
select_by(param=param) if you want to find all the names that have to do
with a parameter.
names becomes a list
I hope this helps a little.
I think you misunderstood Paul's question (which I'm also waiting for
response)... :)
What Paul is asking is: given this mapping:
mapper(User, users_table)
mapper(Address, addresses_table, properties={
'user' : relation(User, backref='addresses', lazy=False)
})
We are able to know that Address class has a reference to User class
by introspecting its mapper's properties:
q = session.query(Address)
q.mapper.properties['user']
sqlalchemy.orm.properties.PropertyLoader object at 0x013094D0
However, if the relation is declared this way:
mapper(Address, addresses_table)
mapper(User, users_table, properties={
'addresses' : relation(Address, backref='user', lazy=False)
})
... our introspection gives us:
q = session.query(Address)
q.mapper.properties['user']
Traceback (most recent call last):
File pyshell#42, line 1, in -toplevel-
q.mapper.properties['user']
KeyError: 'user'
But Address actually has a user property... :(
If we need to introspect both Address-user and User-addresses, one
solution is to not use the backref ... :
mapper(User, users_table, properties={
'addresses' : relation(Address, lazy=False)})
mapper(Address, addresses_table, properties={
'user' : relation(User, lazy=False)})
q = session.query(User)
q.mapper.properties['addresses']
sqlalchemy.orm.properties.PropertyLoader object at 0x01313F70
q = session.query(Address)
q.mapper.properties['user']
sqlalchemy.orm.properties.PropertyLoader object at 0x013134F0
BTW, one practical use of this introspection can be found at:
http://trac.turbogears.org/ticket/1582
On Oct 29, 2007 11:21 AM, Paul Johnston [EMAIL PROTECTED] wrote:
Hi,
How do I get a list of the relations a mapper has? I've been using
mapper.properties, but have just realised this doesn't pick up backrefs.
/me too...:)
Any ideas? Thanks,
I also want to know that...
Cheers,
Roger
--~--~-~--~~~---~--~~
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: How to get list of relations
On Oct 30, 2007, at 10:16 AM, Roger Demetrescu wrote: If we need to introspect both Address-user and User-addresses, one solution is to not use the backref ... : use mapper.get_property(name) and mapper.iterate_properties(). I've considered removing properties as a public accessor since it serves no useful purpose. --~--~-~--~~~---~--~~ 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: How to get list of relations
Mike,
use mapper.get_property(name) and mapper.iterate_properties(). I've
considered removing properties as a public accessor since it serves
no useful purpose.
This doesn't work for me - the following code outputs:
[Column('id', Integer(), primary_key=True, nullable=False)]
[Column('val', String(length=None,convert_unicode=False))]
I can do a test case without Elixir if needed, but I don't think that will
change the result.
from sqlalchemy import *
from elixir import *
__metadata__ = MetaData('mssql://./test')
class Paj(Entity):
val = Field(String)
class Bob(Entity):
paj = ManyToOne(Paj, primary_key=True, backref='bob')
silly = Field(Integer)
for a in Paj.mapper.iterate_properties:
print a.columns
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: How to get list of relations
Hi, use mapper.get_property(name) and mapper.iterate_properties (). I've considered removing properties as a public accessor since it serves no useful purpose. Ok, I found a hacky way that does what I need: [(n, getattr(obj, n)) for n in dir(obj) if isinstance(getattr(obj, n), sqlalchemy.orm.attributes.InstrumentedAttribute)] That'll do me for now. 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: How to get list of relations
Hi, Ok, I found a hacky way that does what I need: [(n, getattr(obj, n)) for n in dir(obj) if isinstance(getattr(obj, n), sqlalchemy.orm.attributes.InstrumentedAttribute)] Ooops, not quite what I need. How do I go from a CollectionAttributeImpl to a mapper? 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: How to get list of relations
On Oct 30, 2007, at 11:25 AM, Paul Johnston wrote:
Mike,
use mapper.get_property(name) and mapper.iterate_properties (). I've
considered removing properties as a public accessor since it serves
no useful purpose.
This doesn't work for me - the following code outputs:
[Column('id', Integer(), primary_key=True, nullable=False)]
[Column('val', String(length=None,convert_unicode=False))]
I can do a test case without Elixir if needed, but I don't think
that will change the result.
from sqlalchemy import *
from elixir import *
__metadata__ = MetaData('mssql://./test')
class Paj(Entity):
val = Field(String)
class Bob(Entity):
paj = ManyToOne(Paj, primary_key=True, backref='bob')
silly = Field(Integer)
for a in Paj.mapper.iterate_properties:
print a.columns
what is it youre looking for ? those columns are associated with
ColumnProperty objects associated with your mapper. you want to
filter out and get just the PropertyLoaders, those correspond to
relation().
--~--~-~--~~~---~--~~
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: How to get list of relations
On 10/30/07, Paul Johnston [EMAIL PROTECTED] wrote:
Mike,
use mapper.get_property(name) and mapper.iterate_properties (). I've
considered removing properties as a public accessor since it serves
no useful purpose.
This doesn't work for me - the following code outputs:
[Column('id', Integer(), primary_key=True, nullable=False)]
[Column('val', String(length=None,convert_unicode=False))]
I can do a test case without Elixir if needed, but I don't think that will
change the result.
from sqlalchemy import *
from elixir import *
__metadata__ = MetaData('mssql://./test')
class Paj(Entity):
val = Field(String)
class Bob(Entity):
paj = ManyToOne(Paj, primary_key=True, backref='bob')
silly = Field(Integer)
You are missing a compile call before you can iterate properties.
try adding:
Paj.mapper.compile()
But maybe that should be done automatically in iterate_properties.
for a in Paj.mapper.iterate_properties:
print a.columns
--
Gaëtan de Menten
http://openhex.org
--~--~-~--~~~---~--~~
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: How to get list of relations
Hey whats going on. I am a new sqlalchemist as well but lets see if this helps any. This is how I am getting a list of all names that corrispond with my document names class. names = [ c.name for c in model.Document.select_by(param=param) ] So I am just collecting all the names from my Document table. I added select_by(param=param) if you want to find all the names that have to do with a parameter. names becomes a list I hope this helps a little. On Oct 29, 2007 11:21 AM, Paul Johnston [EMAIL PROTECTED] wrote: Hi, How do I get a list of the relations a mapper has? I've been using mapper.properties, but have just realised this doesn't pick up backrefs. Any ideas? Thanks, 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 -~--~~~~--~~--~--~---
