On 2/13/2014 11:45 AM, Michael Bayer wrote:
So for children above you need to spell out primaryjoin completely which is
primaryjoin=and_(Animal.sire_id == Animal.id_, Animal.dam_id == Animal.id).
Thought I was on the right track but now getting the exception below. Here's
the model:
class
On 2/14/2014 11:50 AM, Michael Bayer wrote:
On Feb 14, 2014, at 12:46 PM, Michael Hipp mich...@redmule.com wrote:
On 2/13/2014 11:45 AM, Michael Bayer wrote:
So for children above you need to spell out primaryjoin completely which is
primaryjoin=and_(Animal.sire_id == Animal.id_
On 2/14/2014 1:51 PM, Michael Bayer wrote:
right this is why reading the docs is better, those have been checked...
remote side for m2o refers to the primary key, so:
The docs says: '...directive is added known as remote_side, which is a Column
or collection of Column objects that indicate
On 2/14/2014 2:34 PM, Michael Bayer wrote:
A basic fact of a self referential relationship is that you're building a tree.
The root of the tree has to be NULL and I'd advise against trying to work
around that.
Now if you wanted to in fact assign the object's own primary key to the foreign
On 2/14/2014 3:36 PM, Michael Bayer wrote:
the django ORM would write an autogenerated primary key value to a foreign
key column at the same time in a single INSERT? What magic might they have
discovered there? (hint: i am sure they don't do that)
Naw. If you recall I was supplying the pkey
I'm trying to do something like this:
class Animal(Base):
__tablename__ = 'animals'
id_ = Column(Integer, primary_key=True)
sire_id = Column(Integer, ForeignKey('animals.id_'))
dam_id = Column(Integer, ForeignKey('animals.id_'))
sire = relationship('Animal',
On 2/13/2014 11:06 AM, Josh Kuhn wrote:
I think you need to use the remote_side argument for the children
relationship, since it's the same table
http://docs.sqlalchemy.org/en/rel_0_9/orm/relationships.html#adjacency-list-relationships
Thanks. I'm just not sure how to specify it when there
On 2/13/2014 11:04 AM, Michael Bayer wrote:
On Feb 13, 2014, at 11:53 AM, Michael Hipp mich...@redmule.com wrote:
I don't see a first_owner relationship defined above, so the above example
is not complete. The approach using foreign_keys is the correct approach to
resolving ambiguity in join
On 2/13/2014 11:45 AM, Michael Bayer wrote:
primaryjoin=and_(Animal.sire_id == Animal.id_, Animal.dam_id == Animal.id)
Thank you. That works great. And thanks for the explanation.
Michael
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Hello,
I have a database in PostgreSQL that is built and updated using Django 1.2 and
I'd like to access it with SA. Are there any quick pointers you could offer to
get me started on the best way to do that (e.g. duplicate Django's models.py in
SA, use reflection, etc.)? The tables have a
Doing a simple query like this, I just want to get a list of the pkeys in the
table:
q = select([mytable.c.id,])
pkey_list = engine.execute(q).fetchall()
What I get back looks like:
[(1,), (2,)]
But what I need is just:
[1, 2]
It's easy enough to make that happen in Python, but was
Is there anything that should be done to close an engine just before
application termination?
I don't see a .close() method but there is a .dispose() method.
Thanks,
Michael
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a==b come out True?
Thanks,
Michael Hipp
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I have an ORM object that gets loaded once during program run and never changes.
sess = Session()
unchanging = sess.query(Unchanging).get(1)
sess.close() # it is now detached
I then need to tell other objects about about it, having a many-to-one
relationship to 'unchanging':
sess1 =
On 2012-02-08 9:50 AM, Michael Bayer wrote:
unchanging = sess1.merge(unchanging, dont_load=True)
Thanks, Michael this seems to do what I need.
But I notice in the docs the kwarg appears to be 'load=False'. Am I looking at
the wrong thing?
/latest/core/schema.html#sqlalchemy.schema.Sequence
Thanks,
Michael Hipp
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On 2012-01-05 1:24 PM, Michael Bayer wrote:
On Jan 5, 2012, at 9:57 AM, Michael Hipp wrote:
Working from the many-many example in the tutorial [1], it has an association
table like this:
post_keywords = Table('post_keywords', Base.metadata,
Column('post_id', Integer, ForeignKey('posts.id
Working from the many-many example in the tutorial [1], it has an association
table like this:
post_keywords = Table('post_keywords', Base.metadata,
Column('post_id', Integer, ForeignKey('posts.id')),
Column('keyword_id', Integer, ForeignKey('keywords.id'))
)
Normally to just empty
On 2011-12-28 10:58 AM, Michael Bayer wrote:
detach(), also nice.
This seems most descriptive of what is actually taking place. I poured over the
docs for some time looking for the detach() method.
Michael
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How important is it to call session.close() when done with a session?
Will things be automatically cleaned-up if all references to a session
go out of scope?
Thanks,
Michael
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On 2011-12-08 4:11 PM, Michael Bayer wrote:
On Dec 8, 2011, at 4:55 PM, Michael Hipp wrote:
I'm getting a dirty indication on a particular ORM object from
session.is_modified(rec, passive=True) and also that same rec shows up in
session.dirty. But I can't figure out where/how it's been
Could someone point me to a doc page that explains how to enforce a
range limit on a Numeric type. I have some monetary values that I want
to force to always be = Decimal('0.00').
Thanks,
Michael
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Can someone help me understand why I can't seem to do a simple left outer join
between these two tables:
q = self.session.query(Car, Invoice.id_)
q = q.outerjoin(Car, Invoice)
sqlalchemy.exc.ArgumentError: Can't find any foreign key relationships between
'cars' and 'cars'.
This works:
Seller = aliased(Dealer)
Buyer = aliased(Dealer)
q = self.session.query(Car, Seller.name, Buyer.name)
q = q.outerjoin((Car.seller, Seller), (Car.buyer, Buyer))
This doesn't:
Seller = aliased(Dealer)
Buyer = aliased(Dealer)
q =
Can someone show me the gist of how to construct an SA query that
produces SQL* of the form
SELECT ARRAY(SELECT ... FROM ... WHERE ...) as array_col
Thanks,
Michael
*
http://www.postgresql.org/docs/8.4/interactive/sql-expressions.html#SQL-SYNTAX-ARRAY-CONSTRUCTORS
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On 11/9/2010 3:55 PM, Gunnlaugur Briem wrote:
select([
func.ARRAY(
select([t.c.value])
.where(t.c.id3)
.as_scalar()
)
.label('array_col')
])
Thank you! That works swimmingly.
I now know why my search didn't turn up anything as it is evidently one of
those If the
On 11/6/2010 12:15 AM, Christopher Grebs wrote:
this is just some specific PostgreSQL behaviour. If there's an error
in a transaction it closes the transaction and nothing can be done
with it anymore. You need to catch such errors and close the session
or at least commit to close the
I'm doing a simple query like this, to get a list of dealers with open invoices:
session.query(Invoice.dealer_id, Dealer.name).
outerjoin((Dealer, Invoice.dealer)).
group_by(Invoice.dealer_id, Dealer.name).
all()
Which produces this SQL:
SELECT invoices.dealer_id AS
On 11/5/2010 2:50 PM, Michael Hipp wrote:
That SQL runs perfectly when given directly to PostgreSQL, but SQLAlchemy is
reporting a DB-API error:
sqlalchemy.exc.InternalError: (InternalError) current transaction is
aborted, commands ignored until end of transaction block
Nevermind. I noticed
If I do this:
item1 = Item() # a new item
self.sess.add(item1)
self.sess.begin(subtransactions=True) # sub transaction
item2 = Item() # another
self.sess.add(item2)
self.sess.rollback() # rollback sub trans
cnt = self.sess.query(Item).count() # how many?
That
On 11/1/2010 10:19 AM, Michael Bayer wrote:
SAVEPOINT. This is the technique the average user wants to use.
Thanks for that.
Pertinent documentation: begin(): When a rollback is issued, the
subtransaction will directly roll back the innermost *real* transaction.
rollback(): This method rolls
On 11/1/2010 11:33 AM, Michael Bayer wrote:
OK I think in this case, as in many others, is that subtransactions are not
an easy to learn feature, hence it is controlled by a flag that is off by default. ...
... for features that aren't intended for typical use
Then perhaps say that. This
On 11/1/2010 3:12 PM, Michael Bayer wrote:
new section:
http://www.sqlalchemy.org/docs/orm/session.html#using-subtransactions
This section now attempts to explain the full purpose and rationale of the
subtransactions feature including an example. Hope it's clear.
Thank you, looks
I have a model that looks something like this:
TRANS_CODES = ( 'SellCar', 'BuyCar', 'BuyFee', 'SellFee',
'Gas/Fuel', 'Detail', 'Wash/Vac', 'Trans/Hauling',
'Service/Repair', 'DraftFee', 'Misc', 'Cash',
'CheckPaid', 'CheckRcvd', 'FloorPlan', 'Draft')
class Trans(Base):
__tablename__
On 8/24/2010 9:47 PM, Michael Bayer wrote:
Michael Hipp wrote:
How do I make a copy of an orm object such that modifications to the
copy do not affect the original?
The mapped object has a member _sa_instance_state that you basically
don't want to transfer to your new object.You want
On 10/16/2010 12:52 PM, Michael Bayer wrote:
On Oct 16, 2010, at 1:02 PM, Michael Hipp wrote:
On 8/24/2010 9:47 PM, Michael Bayer wrote:
Michael Hipp wrote:
How do I make a copy of an orm object such that modifications to the
copy do not affect the original?
The mapped object has a member
On 10/16/2010 1:55 PM, Michael Bayer wrote:
On Oct 16, 2010, at 2:03 PM, Michael Hipp wrote:
On 10/16/2010 12:52 PM, Michael Bayer wrote:
On Oct 16, 2010, at 1:02 PM, Michael Hipp wrote:
On 8/24/2010 9:47 PM, Michael Bayer wrote:
Michael Hipp wrote:
How do I make a copy of an orm object
If I have a column defined like this:
qty = Column(Numeric, nullable=False, default=Decimal('1'))
When is the default applied? At commit()?
Michael
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On 10/15/2010 5:30 PM, Michael Hipp wrote:
If I have a column defined like this:
qty = Column(Numeric, nullable=False, default=Decimal('1'))
When is the default applied? At commit()?
Nevermind. Finally found it in the docs, appears it happens at INSERT time.
Thanks,
Michael
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On 9/22/2010 10:27 AM, Michael Bayer wrote:
Michael, thanks so much for taking the time to compose a very thorough answer.
If you could indulge a few clarifications/suggestions ...
So here, the value of None for car.auction, merges into the session which
becomes a pending change. The
On 8/26/2010 8:55 PM, Mike Conley wrote:
On Thu, Aug 26, 2010 at 4:21 PM, Michael Hipp mich...@hipp.com
mailto:mich...@hipp.com wrote:
Is there a way to set 'echo' at any time? Everything I can find sets it
when the engine is created and doesn't seem to change it afterward.
You can
On 9/22/2010 11:21 AM, Michael Hipp wrote:
new = Car()
new.id_ = old.id_
new = sess.merge(new)
new.auction = old.auction # do this *after* merge
sess.commit()
This seems to work and ...
Bah. I spoke too soon - it just doesn't throw an exception. But without
explicitly setting
On 9/22/2010 5:24 PM, Michael Bayer wrote:
Here's the problem. The term a blank record is meaningless.
Well, no, it's not. It's exactly what I get when I do new=Item() and commit().
It's very well defined, precise, and repeatable.
Trying to make other tools guess this for you seems to be
On 9/20/2010 10:54 AM, Michael Hipp wrote:
On 9/20/2010 10:09 AM, Michael Hipp wrote:
On 9/20/2010 9:38 AM, Michael Hipp wrote:
Scratch that ... found this message:
http://www.mail-archive.com/sqlalchemy@googlegroups.com/msg18598.html
which says I should be able to do a 'SIMILAR TO' construct
I need to empty an item (row). I thought to do this:
new = Item() # create a new empty object
new.id_ = old.id_ # copy certain other fields also
self.session.expunge(old)
self.session.add(new)
self.session.commit()
But it seems SA still tries to save it with an INSERT. (I
On 9/21/2010 7:23 AM, Michael Bayer wrote:
On Sep 21, 2010, at 8:12 AM, Michael Hipp wrote:
On 9/20/2010 10:54 AM, Michael Hipp wrote:
On 9/20/2010 10:09 AM, Michael Hipp wrote:
On 9/20/2010 9:38 AM, Michael Hipp wrote:
Scratch that ... found this message:
http://www.mail-archive.com
On 9/21/2010 7:31 AM, Michael Hipp wrote:
I need to empty an item (row). I thought to do this:
new = Item() # create a new empty object
new.id_ = old.id_ # copy certain other fields also
self.session.expunge(old)
self.session.add(new)
self.session.commit()
But it seems SA still tries to save
On 9/21/2010 8:17 PM, Michael Bayer wrote:
It definitely does not attempt an INSERT if id_ is set to a non-None value,
assuming that row already exists in the DB, without something else in your
model/usage causing that to happen.If id_ is None or the given id_ doesn't
exist in the DB, you
On 9/20/2010 9:38 AM, Michael Hipp wrote:
Scratch that ... found this message:
http://www.mail-archive.com/sqlalchemy@googlegroups.com/msg18598.html
which says I should be able to do a 'SIMILAR TO' construct which is perhaps
somewhat more lightweight than a full regexp.
Can someone show me
On 9/20/2010 10:09 AM, Michael Hipp wrote:
On 9/20/2010 9:38 AM, Michael Hipp wrote:
Scratch that ... found this message:
http://www.mail-archive.com/sqlalchemy@googlegroups.com/msg18598.html
which says I should be able to do a 'SIMILAR TO' construct which is perhaps
somewhat more lightweight
On 9/20/2010 10:57 AM, Michael Bayer wrote:
On Sep 20, 2010, at 11:54 AM, Michael Hipp wrote:
On 9/20/2010 10:09 AM, Michael Hipp wrote:
On 9/20/2010 9:38 AM, Michael Hipp wrote:
Scratch that ... found this message:
http://www.mail-archive.com/sqlalchemy@googlegroups.com/msg18598.html
which
On 9/14/2010 2:23 PM, Michael Hipp wrote:
Is it possible to use a regexp in a like() clause? Or some other way to achieve
something similar?
Can anyone suggest an approach to search a field with a regexp?
Thanks,
Michael
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Is it possible to use a regexp in a like() clause? Or some other way to achieve
something similar?
Thanks,
Michael
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Is there a way to set 'echo' at any time? Everything I can find sets it when
the engine is created and doesn't seem to change it afterward.
Thanks,
Michael
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On 8/24/2010 9:47 PM, Michael Bayer wrote:
Michael Hipp wrote:
How do I make a copy of an orm object such that modifications to the
copy do not affect the original?
x = MyObject()
for a in dir(myoldobject):
if not a.startswith('_'):
setattr(x, a, getattr
I'm holding an orm object that will have changes made to it. Once done it will
be passed to the business logic layer that will have to make decisions from the
before and after state of the object...
What's the best way to get an object, save its state ('before'), modify it
('after) without
On 8/24/2010 1:51 PM, Michael Bayer wrote:
On Aug 24, 2010, at 2:08 PM, Michael Hipp wrote:
I'm holding an orm object that will have changes made to it. Once done it will
be passed to the business logic layer that will have to make decisions from the
before and after state of the object
I'm trying to do exactly what is described here:
http://www.sqlalchemy.org/docs/mappers.html#adjacency-list-relationships
But I'm using declarative. Here's what I have but it fails with the exception
below:
class Option(Base):
__tablename__ = 'options'
id_ = Column(Integer,
On 8/21/2010 6:00 PM, Michael Bayer wrote:
On Aug 21, 2010, at 5:16 PM, Michael Hipp wrote:
How do I make this work with declarative?
If you were to use string literals with remote_side here, its the full expression would
be a string, i.e. remote_side=Option.id_. But that's not needed here
On 8/19/2010 5:24 AM, Chris Withers wrote:
Michael Hipp wrote:
SQLAlchemy seems pretty smart about updating only the changed columns
in an orm object...
If I have an orm object. Something changes one of the columns. Just
before I commit() the session, is there a way to tell which columns
SQLAlchemy seems pretty smart about updating only the changed columns in an orm
object...
If I have an orm object. Something changes one of the columns. Just before I
commit() the session, is there a way to tell which columns will be updated vs
those that are unchanged?
Any way to ascertain
The little diddly below is comparing performance of orm access vs sql
expression language.
When I run it with number=1 I get a 5.8x advantage for sql. When I run it 10
times I get a 2.7x advantage. The actual numbers are, respectively:
1.47375132
0.25630808
5.45569524
1.96911144
Is this a
I'm doing something like this where each Item has 2 ForeignKeys to Dealer for
buyer and seller:
seller = dealers.alias('seller')
buyer = dealers.alias('buyer')
engine.execute(select([items, seller.c.name, buyer.c.name]).fetchall()
When I do this the seller and buyer name end up in the
On 8/16/2010 5:12 PM, Conor wrote:
On 08/16/2010 04:47 PM, Michael Hipp wrote:
I'm doing something like this where each Item has 2 ForeignKeys to
Dealer for buyer and seller:
seller = dealers.alias('seller')
buyer = dealers.alias('buyer')
engine.execute(select([items, seller.c.name
I'm obviously missing some key concept as regards the management of sessions.
This seemingly simple usage fails:
def get_new():
sess = Session()
new = Something() # new orm object
sess.add(new)
sess.commit()
sess.close()
return new
new = get_new() # request a new
, at 12:53 PM, Michael Hipp wrote:
I'm obviously missing some key concept as regards the management of
sessions. This seemingly simple usage fails:
def get_new():
sess = Session()
new = Something() # new orm object
sess.add(new)
sess.commit()
sess.close()
return new
new = get_new() # request a new
On 8/14/2010 2:29 PM, Michael Bayer wrote:
The approach above may be fine for your needs but I wouldn't encourage it. The
demarcation of transaction boundaries shouldn't be an ad-hoc thing IMO and
granular functions shouldn't be deciding whether or not they are setting up a
transaction.
On 8/6/2010 9:04 PM, Michael Hipp wrote:
Can someone help me figure out why I keep getting the error below. Here
are my 3 models. It's a simple many-one on banks-dealer and reps-dealer.
class Dealer(Base):
__tablename__ = 'dealers'
id_ = Column(Integer, primary_key=True)
reps = relationship
Can someone help me figure out why I keep getting the error below. Here
are my 3 models. It's a simple many-one on banks-dealer and reps-dealer.
class Dealer(Base):
__tablename__ = 'dealers'
id_ = Column(Integer, primary_key=True)
reps = relationship('Rep', order_by='Rep.lname',
On 8/4/2010 10:03 PM, Mike Conley wrote:
On Wed, Aug 4, 2010 at 9:39 PM, Michael Hipp mich...@hipp.com
mailto:mich...@hipp.com wrote:
Can someone tell me why this code won't create any tables? The
tables are defined in another file that calls declarative_base().
I presume
On 8/5/2010 8:26 AM, Mike Conley wrote:
On Thu, Aug 5, 2010 at 6:29 AM, Michael Hipp mich...@hipp.com
mailto:mich...@hipp.com wrote:
On 8/4/2010 10:03 PM, Mike Conley wrote:
Thanks. But by the time I'm done there will be at least a dozen of
those otherfiles. Which one do I get
Can this be made to work?
session = Session()
rec = MyModel() # create a record
session.close()
# Sometime later
session = Session()
rec.name = Fred # modify the record
session.commit() # try to save modified record
session.close()
Does the session have to be global to this
On 8/5/2010 11:03 AM, Michael Bayer wrote:
On Aug 5, 2010, at 11:54 AM, Michael Hipp wrote:
Can this be made to work?
session = Session()
rec = MyModel() # create a record
session.close()
# Sometime later
session = Session()
rec.name = Fred # modify the record
session.commit
Hello, a couple of really basic questions ...
1) How do I write a query beforehand that will be evaluated later at some other
place in the code? (Note that the session hopefully won't exist until that
later time.) Also, certain parameters may need to be passed to the query at
eval time (e.g.
Can someone tell me why this code won't create any tables? The tables
are defined in another file that calls declarative_base().
I presume the problem is that it doesn't know which tables to create. If
so, how do I tell it what tables to create?
Base = declarative_base()
database =
This is a really dumb noob question...
I know how to create an engine, a Session, and a session.
I see how to do session.close().
How do I close the engine?
(i.e. How do I close all connections to the database cleanly so my application
can exit and not leave the database server hanging?)
this by using a field like 'edit_sequence' which is an
incrementing sequence where the value in the db must match that in the UPDATE.
Does SA have such a feature or something like it?
Thanks,
Michael Hipp
Heber Springs, Arkansas, USA
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