[sqlalchemy] orm query - join on inner query
How can i implement the following query with sqlalchemy.orm objects?
SELECT columns.*
FROM columns AS col
JOIN
(
SELECT object_id, revision
FROM columns
GROUP BY id, revision
HAVING revision = 20
) AS lr ON col.object_id = lr.object_id AND col.revision =
lr.revision;
Non syntactically correct example :
from sqlalchemy import schema, types, orm, create_engine
# Setup everything
engine = create_engine('sqlite://:memory:')
metadata = schema.Metadata(bind=engine)
ColumnsTable = schema.Table('columns'
, schema.Column('id', types.Integer, primary_key=True)
, schema.Column('object_id', types.Integer)
, schema.Column('name', types.String)
, schema.Column('revision', types.Integer)
, metadata)
class ColumnOrm (object):
pass
metadata.create_all()
orm.mapper(ColumnOrm, ColumnsTable)
session = orm.create_session(bind=engine, autocommit=True)
# Now for the query
# lr means latest revision
SELECT columns.*
FROM columns AS col
JOIN
(
SELECT object_id, revision
FROM columns
GROUP BY id, revision
HAVING revision = 20
) AS lr ON col.object_id = lr.object_id AND col.revision =
lr.revision;
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[sqlalchemy] Adding MapperExtensions after Mappers created
How do i add a MapperExtension to a mapper after the mapper has been created with the mapper() function --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Mapped Orm Object Notifier
Hi I've been reading through the documentation and i can't see an existing feature for this. The table i'm working with stores properties about part of my program. I get a record from the session.queryone() function and i pass that around. The record is somewhere in a properties change dialog box and somewhere else as a label. Is there currently a way of having the class sets the label to register a listener with the orm record so that when the record is updated, It notifies the listener which updates the label? Regards, Jar. PS, I was thinking tonight that sqlAchemy would make an awesome content for a university subject. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Mapped Orm Object Notifier
class OrmRecord(object): def _get_column_value(self, name): # return self.__dict__[name] return getattr(self, name) def _set_column_value(self, name, value): val = setattr(self, name, value) self._notify_change_functions() # Return result just because return val def add_change_function(self, instance, function): Add Change Function Add a function to this record that will be modified when this record is changed This function will be called and passed the record it wants to be notified about instance The instance of the object to be called back function The function to be called and passed the instance try: self._change_functions except AttributeError: self._change_functions = weakref.WeakKeyDictionary () self._change_functions[instance] = function def _notify_change_functions(self): try: self._change_functions except AttributeError: return for instance in self._change_functions: self._change_functions[instance](self) self._OrmRecord = OrmRecord print 'Mapped ' + self.schema_table_name + '\n\t' + str (self._OrmRecord) + '\n\t' + str(metadata.tables [self.schema_table_name]) self._mapper = mapper(self._OrmRecord, self._metadata_table) This is the code i put together I set the value of the orm_record using the setter and getter functions above. Anyone know of a more sqlalchemy way of doing it? --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] SQLAlchemy Migrate
Hi All I'm writing a metadata based schema migration tool. As SQLAlchemy doesn't support much schema modification. I will implement a complete set of schema migration functions one way or another for several of the SQLAlchemy supported databases. My question is, Where should these function reside? Options are : 1) Branch SQLAlchemy and make the modifications 2) Branch SQLAlchemy Migrate and make the modifications 3) Write the code and not distribute it cause no one cares. 4) ? Suggestions ? PS, Thanks Michael Bayer, SQLAlchemy is great. --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SQLAlchemy Migrate
Yes, Option 2 - However, From the example documentation, Its doesn't implement everything. Although its most of the way there - So option 2 is looking good to me. On Mar 6, 1:23 am, Lawrence Oluyede l.oluy...@gmail.com wrote: On Thu, Mar 5, 2009 at 10:03 AM, jarrod.ches...@gmail.com jarrod.ches...@gmail.com wrote: I'm writing a metadata based schema migration tool. Keep in mind there are some other projects like http://code.google.com/p/sqlalchemy-migrate/ HTH -- Lawrence Oluyede [eng]http://oluyede.org-http://twitter.com/lawrenceoluyede [ita]http://neropercaso.it-http://twitter.com/rhymes --~--~-~--~~~---~--~~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Create tables with metadata
Hi
I've scoured the documentation and i can't find any info on how to
create a column using metadata.
from sqlalchemy import engine
from sqlalchemy import schema
from sqlalchemy import types
_config_dbengine = engine.create_engine('sqlite:tmp/db')
_config_metadata = schema.MetaData(_config_dbengine, reflect=True)
table = _config_metadata.tables['table_name']
table.append_column(schema.Column('id', types.Integer,
primary_key=True, autoincrement=True))
This is the steps i'm using but the column doesn't get created.
Any ideas?
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[sqlalchemy] Re: Create tables with metadata
Doesn't get created in the database.
How do i add columns to tables already defined in the database after i
have reflected them into the metadata
On Dec 12, 12:59 am, Empty mtr...@gmail.com wrote:
Hi,
On Thu, Dec 11, 2008 at 8:12 AM, jarrod.ches...@gmail.com
jarrod.ches...@gmail.com wrote:
Hi
I've scoured the documentation and i can't find any info on how to
create a column using metadata.
from sqlalchemy import engine
from sqlalchemy import schema
from sqlalchemy import types
_config_dbengine = engine.create_engine('sqlite:tmp/db')
_config_metadata = schema.MetaData(_config_dbengine, reflect=True)
table = _config_metadata.tables['table_name']
table.append_column(schema.Column('id', types.Integer,
primary_key=True, autoincrement=True))
This is the steps i'm using but the column doesn't get created.
Doesn't get created where? In the database? That's not going to happen.
Are you saying it's not included as part of the table definition?
Michael
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