Re: [sqlalchemy] polymorphic inheritance and unique constraints
sorry, i mean i couldn't test it earlier, when i first asked the
question :) it was not another co-worker, lol.
cheers,
richard.
On 04/13/2015 06:30 PM, Mike Bayer wrote:
On 4/13/15 4:59 PM, Richard Gerd Kuesters | Pollux Automation wrote:
well, this didn't work with upstream 1.0 - sorry, I was in another
project and couldn't test it myself.
you're not doing the same thing this user was doing in any case...
Traceback (most recent call last):
File database_test.py, line 46, in module
from plx.db.core import *
File ../src/plx/db/core.py, line 901, in module
UniqueConstraint(ContainerInstance.batch_id,
ContainerAggregation.container_descriptor_id,)
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2464, in __init__
ColumnCollectionMixin.__init__(self, *columns,
_autoattach=_autoattach)
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2393, in __init__
self._check_attach()
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2429, in _check_attach
table.description)
sqlalchemy.exc.ArgumentError: Column(s)
'container_aggregation.fk_container_descriptor_id' are not part of
table 'container_instance'.
I got sqlalchemy from git, today.
sqlalchemy.__version__
'1.0.0'
container_aggretation is a subclass of container_instance. I'm not
using concrete inheritance here, may this be the problem?
anything else, it's Python 2.7.9 + Linux + PostgreSQL 9.4.1.
cheers,
richard.
On 03/24/2015 08:49 PM, Michael Bayer wrote:
are these two separate constraints? I just looked and it seems like they are
distinct.
I just added a fix to 1.0 because someone was hacking around something similar
to this.
The easiest way to get these for the moment is just to create the
UniqueConstraint outside of the class definition.
class Foo(Base):
# …
class Bar(Foo):
# …
UniqueConstraint(Bar.x, Foo.y)
that way all the columns are set up, should just work.
Richard Gerd Kuesters | Polluxrich...@pollux.com.br wrote:
well, understanding better the docs for column conflicts, can i use a
declared_attr in a unique constraint? if yes, my problem is solved :)
On 03/24/2015 10:33 AM, Michael Bayer wrote:
Richard Gerd Kuesters | Pollux
rich...@pollux.com.br
wrote:
hi all!
i'm dealing with a little problem here. i have a parent table and its two
inheritances. there is a value that both children have and must be unique along
either types. is there a way to move this column to the parent and use a
constraint in the child? my implementation is postgres 9.4+ with psycopg2 only.
if this is single table inheritance then the constraint would most ideally
be placed on the parent class.
if you’re trying to make this “magic” such that you can semantically keep
the unique constraints on the child classes, you’d need to build out a
conditional approach within @declared_attr. IMO I think this is an idealized
edge case that in the real world doesn’t matter much - just do what works
(put the col / constraint on the base).
the approach is described at
http://docs.sqlalchemy.org/en/rel_0_9/orm/extensions/declarative/inheritance.html#resolving-column-conflicts
.
You’d need to make this work for both the column and the constraint.
as a simple example (i'm just creating this example to simplify things), this
works:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(bar_id, child1_specific_name,), # works, bar_id is
in MyChild1
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(bar_id, child2_specific_code,), # works, bar_id is
in MyChild2
)
but i would like to do this, if possible:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64
Re: [sqlalchemy] polymorphic inheritance and unique constraints
well, this didn't work with upstream 1.0 - sorry, I was in another
project and couldn't test it myself.
Traceback (most recent call last):
File database_test.py, line 46, in module
from plx.db.core import *
File ../src/plx/db/core.py, line 901, in module
UniqueConstraint(ContainerInstance.batch_id,
ContainerAggregation.container_descriptor_id,)
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2464, in __init__
ColumnCollectionMixin.__init__(self, *columns, _autoattach=_autoattach)
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2393, in __init__
self._check_attach()
File
/home/richard/.pyenv/versions/vpak-pollux-2.7.9/lib/python2.7/site-packages/sqlalchemy/sql/schema.py,
line 2429, in _check_attach
table.description)
sqlalchemy.exc.ArgumentError: Column(s)
'container_aggregation.fk_container_descriptor_id' are not part of table
'container_instance'.
I got sqlalchemy from git, today.
sqlalchemy.__version__
'1.0.0'
container_aggretation is a subclass of container_instance. I'm not using
concrete inheritance here, may this be the problem?
anything else, it's Python 2.7.9 + Linux + PostgreSQL 9.4.1.
cheers,
richard.
On 03/24/2015 08:49 PM, Michael Bayer wrote:
are these two separate constraints? I just looked and it seems like they are
distinct.
I just added a fix to 1.0 because someone was hacking around something similar
to this.
The easiest way to get these for the moment is just to create the
UniqueConstraint outside of the class definition.
class Foo(Base):
# …
class Bar(Foo):
# …
UniqueConstraint(Bar.x, Foo.y)
that way all the columns are set up, should just work.
Richard Gerd Kuesters | Pollux rich...@pollux.com.br wrote:
well, understanding better the docs for column conflicts, can i use a
declared_attr in a unique constraint? if yes, my problem is solved :)
On 03/24/2015 10:33 AM, Michael Bayer wrote:
Richard Gerd Kuesters | Pollux
rich...@pollux.com.br
wrote:
hi all!
i'm dealing with a little problem here. i have a parent table and its two
inheritances. there is a value that both children have and must be unique along
either types. is there a way to move this column to the parent and use a
constraint in the child? my implementation is postgres 9.4+ with psycopg2 only.
if this is single table inheritance then the constraint would most ideally
be placed on the parent class.
if you’re trying to make this “magic” such that you can semantically keep
the unique constraints on the child classes, you’d need to build out a
conditional approach within @declared_attr. IMO I think this is an idealized
edge case that in the real world doesn’t matter much - just do what works
(put the col / constraint on the base).
the approach is described at
http://docs.sqlalchemy.org/en/rel_0_9/orm/extensions/declarative/inheritance.html#resolving-column-conflicts
.
You’d need to make this work for both the column and the constraint.
as a simple example (i'm just creating this example to simplify things), this
works:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(bar_id, child1_specific_name,), # works, bar_id is
in MyChild1
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(bar_id, child2_specific_code,), # works, bar_id is
in MyChild2
)
but i would like to do this, if possible:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
# since both child uses bar_id, why not having it on the parent?
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class
Re: [sqlalchemy] Any recommended approach for creating a new dialect?
Mike, I remember an article of yours where you described much of the process of creating a new dialect for SA, for a Java database if I'm not mistaken. I wasn't able to find it, though. :) On 04/08/2015 01:19 AM, Mike Bayer wrote: On 4/7/15 1:59 PM, Ralph Heinkel wrote: Hello dialect experts, what would be the best approach for creating a SqlAlchemy dialect for a new database system? Are there any recipes available for this area, or is the way to go to read code of existing dialects and derive my own dialect from those? I had a first glance at some built-in dialects, and also some in external packages ... it is not always obvious to me why certain classes and methods have been implemented. The obvious thing is to create a subclass of sqlalchemy.enginedefault.DefaultDialect, but how would I know which methods and class attributes to override/implement, except for going through the trial and error approach? And then there are other classes which are implemented in some dialects, like compiler.DDLCompiler, compiler.GenericTypeCompiler, and so on ... where and how would I start best? Any help would be very much appreciated. Start with the README for new dialects: https://bitbucket.org/zzzeek/sqlalchemy/src/44a9820b4e02f65b3884fa2c016efce9663e4910/README.dialects.rst?at=master that will show the guidelines for writing new dialects. Then to see some examples of that layout, take a look at some of the 3rd party dialects listed at: http://docs.sqlalchemy.org/en/latest/dialects/index.html#production-ready Also the sqlalchemy-access dialect is basically something of a demo for the layout, which I basically put there after extracting it from SQLAlchemy main where it had been for many years. It might not be 100% up to date, but mostly follows that guideline and even passed tests at one point, that's at https://bitbucket.org/zzzeek/sqlalchemy-access. The key thing you'll be doing is running the suite tests, which will be part of the test suite within your own dialect. So yes, you start with a fairly plain subclass of DefaultDialect, then you probably want to get a hello world kind of program going where you just see if create_engine and then engine.execute(select * from table) work at all, and then the suite tests should test a lot more. Ciao ciao Ralph -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com mailto:sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com mailto:sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com mailto:sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com mailto:sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] is True vs ==True
there's this: * import sqlalchemy as sa** ** sa.sql.null()** **sqlalchemy.sql.elements.Null object at 0x7f8a70065c50** ** sa.sql.false()** **sqlalchemy.sql.elements.False_ object at 0x7f8a6fb13050** ** sa.sql.true()** **sqlalchemy.sql.elements.True_ object at 0x7f8a70065c50** * so, you can still use __eq__ and pep-8 will not complain, because there's no way to implement is True or is None. then you'll have this: *session.query(Rischio.c.codice).select_from(Rischio).filter(Rischio.c.peso_gruppo == sa.**sql.true()**)* :) On 03/30/2015 10:52 AM, Jose Soares wrote: Hmm! in this case we must distinguish between the python syntax and the sqlalchemy syntax.:-( j On 30/03/2015 12:37, Simon King wrote: On Mon, Mar 30, 2015 at 10:59 AM, Jose Soares jose.soa...@sferacarta.com wrote: Hi all, While I changed some obsolete syntax as defined in (https://www.python.org/dev/peps/pep-0008/) like (is True instead of ==True) also False and None. I realized that sqlalchemy do not support them What can I do to avoid this behavior? -- print session.query(Rischio.c.codice).select_from(Rischio).filter(Rischio.c.peso_gruppo == True) SELECT caratteristica_rischio.codice AS caratteristica_rischio_codice FROM caratteristica_rischio WHERE caratteristica_rischio.peso_gruppo = true print session.query(Rischio.c.codice).select_from(Rischio).filter(Rischio.c.peso_gruppo is True) SELECT caratteristica_rischio.codice AS caratteristica_rischio_codice FROM caratteristica_rischio WHERE false I don't think you can. SQLAlchemy expressions define an __eq__ method to enable expression == value-style constructs. There is no equivalent hook in Python for the is operator, so there is no way SQLAlchemy could use it. Simon -- Richard Gerd Kuesters Pollux Automation rich...@pollux.com.br mailto:rich...@pollux.com.br | www.pollux.com.br http://www.pollux.com.br •Linhas de Montagem •Inspeção e Testes •Robótica •Identificação e Rastreabilidade •Software para Manufatura -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] Table Views
you can use a select as a mapped object if you want, but i don't know if that's what you're looking for. On 03/26/2015 01:54 PM, Philip Martin wrote: am trying to setup schemas particularly related to financial reference data. The data doesn't change very often, but I want to setup a good schema where changing one table row changes the data in the whole system, but also create table views the most useful aspects of the data reside in one table. For example, say we have something like: -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] polymorphic inheritance and unique constraints
hell yeah! that's exactly what i was looking for :)
is it in the 1.0.0b3 or upstream?
best regards,
richard.
On 03/24/2015 08:49 PM, Michael Bayer wrote:
are these two separate constraints? I just looked and it seems like they are
distinct.
I just added a fix to 1.0 because someone was hacking around something similar
to this.
The easiest way to get these for the moment is just to create the
UniqueConstraint outside of the class definition.
class Foo(Base):
# …
class Bar(Foo):
# …
UniqueConstraint(Bar.x, Foo.y)
that way all the columns are set up, should just work.
Richard Gerd Kuesters | Pollux rich...@pollux.com.br wrote:
well, understanding better the docs for column conflicts, can i use a
declared_attr in a unique constraint? if yes, my problem is solved :)
On 03/24/2015 10:33 AM, Michael Bayer wrote:
Richard Gerd Kuesters | Pollux
rich...@pollux.com.br
wrote:
hi all!
i'm dealing with a little problem here. i have a parent table and its two
inheritances. there is a value that both children have and must be unique along
either types. is there a way to move this column to the parent and use a
constraint in the child? my implementation is postgres 9.4+ with psycopg2 only.
if this is single table inheritance then the constraint would most ideally
be placed on the parent class.
if you’re trying to make this “magic” such that you can semantically keep
the unique constraints on the child classes, you’d need to build out a
conditional approach within @declared_attr. IMO I think this is an idealized
edge case that in the real world doesn’t matter much - just do what works
(put the col / constraint on the base).
the approach is described at
http://docs.sqlalchemy.org/en/rel_0_9/orm/extensions/declarative/inheritance.html#resolving-column-conflicts
.
You’d need to make this work for both the column and the constraint.
as a simple example (i'm just creating this example to simplify things), this
works:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(bar_id, child1_specific_name,), # works, bar_id is
in MyChild1
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(bar_id, child2_specific_code,), # works, bar_id is
in MyChild2
)
but i would like to do this, if possible:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
# since both child uses bar_id, why not having it on the parent?
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child1_specific_name,), # will it
work?
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child2_specific_code,), # will it
work?
)
well, will it work without being a concrete inheritance? :)
best regards,
richard.
--
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Visit
[sqlalchemy] polymorphic inheritance and unique constraints
hi all!
i'm dealing with a little problem here. i have a parent table and its
two inheritances. there is a value that both children have and must be
unique along either types. is there a way to move this column to the
parent and use a constraint in the child? my implementation is postgres
9.4+ with psycopg2 only.
as a simple example (i'm just creating this example to simplify things),
this works:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id),
primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id),
nullable=False)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(bar_id, child1_specific_name,), # works,
bar_id is in MyChild1
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id),
primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id),
nullable=False)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(bar_id, child2_specific_code,), # works,
bar_id is in MyChild2
)
but i would like to do this, if possible:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id),
nullable=False) # since both child uses bar_id, why not having it
on the parent?
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id),
primary_key=True)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child1_specific_name,),
# will it work?
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id),
primary_key=True)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child2_specific_code,),
# will it work?
)
well, will it work without being a concrete inheritance? :)
best regards,
richard.
--
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Re: [sqlalchemy] polymorphic inheritance and unique constraints
thanks again, Mike!
just a question: to make the constraint in the parent, shouldn't i move
other columns that composes the constraint to the parent too?
cheers,
richard.
On 03/24/2015 10:33 AM, Michael Bayer wrote:
Richard Gerd Kuesters | Pollux rich...@pollux.com.br wrote:
hi all!
i'm dealing with a little problem here. i have a parent table and its two
inheritances. there is a value that both children have and must be unique along
either types. is there a way to move this column to the parent and use a
constraint in the child? my implementation is postgres 9.4+ with psycopg2 only.
if this is single table inheritance then the constraint would most ideally
be placed on the parent class.
if you’re trying to make this “magic” such that you can semantically keep
the unique constraints on the child classes, you’d need to build out a
conditional approach within @declared_attr. IMO I think this is an idealized
edge case that in the real world doesn’t matter much - just do what works
(put the col / constraint on the base).
the approach is described at
http://docs.sqlalchemy.org/en/rel_0_9/orm/extensions/declarative/inheritance.html#resolving-column-conflicts.
You’d need to make this work for both the column and the constraint.
as a simple example (i'm just creating this example to simplify things), this
works:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(bar_id, child1_specific_name,), # works, bar_id is
in MyChild1
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(bar_id, child2_specific_code,), # works, bar_id is
in MyChild2
)
but i would like to do this, if possible:
class MyParent(Base):
foo_id = Column(Integer, Sequence('foo_id_seq'), primary_key=True)
foo_name = Column(Unicode(64), nullable=False)
foo_type = Column(Integer, nullable=False)
bar_id = Column(Integer, ForeignKey(AnotherEntity.bar_id), nullable=False)
# since both child uses bar_id, why not having it on the parent?
__mapper_args__ = {
polymorphic_on: foo_type,
polymorphic_identity: 0
}
class MyChild1(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
child1_specific_name = Column(Unicode(5), nullable=False)
child1_baz_stuff = Column(Boolean, default=False)
__mapper_args__ = {
polymorphic_identity: 1
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child1_specific_name,), # will it
work?
)
class MyChild2(MyParent):
foo_id = Column(Integer, ForeignKey(MyParent.foo_id), primary_key=True)
child2_specific_code = Column(UUID, nullable=False)
child2_baz_stuff = Column(Float, nullable=False)
__mapper_args__ = {
polymorphic_identity: 2
}
__table_args__ = (
UniqueConstraint(MyParent.bar_id, child2_specific_code,), # will it
work?
)
well, will it work without being a concrete inheritance? :)
best regards,
richard.
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[sqlalchemy] auto column naming (declarative)
hi all! i remember bumping into this somewhere, but now that i need it, i can't find. Murphy ... well, here's the question: * the company i work have a certain convention on naming columns in the database level, like dt_ for datetime, u_ for unicode, ut_ for unicodetext, and so on. the question is, can't I use a event listener to do this by my own? a type is bound to a format, it's quite simple dict. example: ... last_update = Column(dt_last_update, DateTime, on_update=func, default=func) ... To: ... last_update = Column(DateTime, on_update=func, default=func) # dt_last_update is automatically created since it's a DateTime type (at the database level only) ... best regards, richard. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
Re: [sqlalchemy] auto column naming (declarative)
thanks Mike! i'll be hooking up to this event. i remember using a working example of this a while ago, that's why i questioned :) but there's no problem creating one from scratch :) best regards, richard. On 03/23/2015 01:39 PM, Michael Bayer wrote: the before_parent_attach() event could do this, sure. Might be a little tricky: http://docs.sqlalchemy.org/en/rel_0_9/core/events.html?highlight=before_parent_attach#sqlalchemy.events.DDLEvents.before_parent_attach Richard Gerd Kuesters | Pollux rich...@pollux.com.br wrote: hi all! i remember bumping into this somewhere, but now that i need it, i can't find. Murphy ... well, here's the question: * the company i work have a certain convention on naming columns in the database level, like dt_ for datetime, u_ for unicode, ut_ for unicodetext, and so on. the question is, can't I use a event listener to do this by my own? a type is bound to a format, it's quite simple dict. example: ... last_update = Column(dt_last_update, DateTime, on_update=func, default=func) ... To: ... last_update = Column(DateTime, on_update=func, default=func) # dt_last_update is automatically created since it's a DateTime type (at the database level only) ... best regards, richard. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
