Hi,
Is there a way of telling if a table is inherited from another table
and which tables it inherits from in the Metadata?
Further to this, Is there a way of telling which column definitions
come from which table?
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Is there a way of telling if a table is inherited from another
table and which tables it inherits from in the Metadata?
inheritance is not really sql notion... so
a) look at the mapper.inherits (towards root) and/or
mapper.polymorphic_itereator() (towards leafs)
b) see if table's primary
A good question. I think we agree that both ways can work well...
Usually, I do prefer the less OO style. In your example, a pure
mapping class and business logic in a user manager.
The main reason is that what you call OO style seems to enforce a
lot of arbitrary decisions.
For example, when
i would bundle them into one... but would probably split on another
level. adding items to a user may well be posessions... so it
depends. That might well be a model of User with related stuff, which
is mapped to database in another way (one2many or Relator object/m2m
or whatever), and is
Hi,
I am a new sqlalchemy user. I'm a bit confused by the behavior of the
Numeric data type. Consider the following code:
from sqlalchemy import *
db = create_engine('sqlite:///test.db')
metadata = MetaData()
table = Table('thetable',metadata,Column('x',Numeric(scale=3)),Column
('y',Float))
Its possible that SQLite doesn't respect the scale argument. I'd look
at the full SQL generated to ensure its what you'd expect, then check
sqlite's documentation on this.
Thomas wrote:
Hi,
I am a new sqlalchemy user. I'm a bit confused by the behavior of the
Numeric data type. Consider
SQLite has no concept of fixed decimal types. Take a look at
http://www.sqlite.org/datatype3.html for what is supported.
It might be possible to make an effective TypeDecorator using the decimal
module introduced in Python 2.4. In fact that would probably make a good
recipe for the SQLAlchemy
Hi there,
I've got a crappy legacy database that has a _rowid and an id column
(they have totally separate meanings. In my orm, I want 'id' to map to
_rowid and 'document_id' to map to id in the table. Easy enough -- I
set it up like this:
mapper(Document, documents, properties={
Thanks, I'll look at that but it doesn't sound very concrete.
IE using a foreign key to see if somethings inherited.
Question 1
From the sqlalchemy mapper configuration, PostGreSQLs version of
inheritence sounds like the concrete variary, as it automatically
joins the tables together with a
I'll look into a) do the mappers pick up foreign key constraints and
the polymorphic/inherited details from the metadata when their created
or do you have to specify them? - As a last resort i can query the
data dictionary.
Question 1
From the sqlalchemy mapper configuration, PostGreSQLs version
On Tuesday 14 April 2009 00:13:10 Jarrod Chesney wrote:
I'll look into a) do the mappers pick up foreign key constraints
and the polymorphic/inherited details from the metadata when their
created or do you have to specify them?
both, if ambigious u have to specify manualy.
dunno about the
mapper(Document, documents, properties={
'document_id': documents.c.id, # document_id ORM property
In the past, I have successfully mapped these properties using
synonym, but this time I'm confused because I'm not sure how to
define the synonym to a different column name. How do I
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