Re: Multiple EO classes inheriting from one abstract superclass?
Re: Multiple EO classes inheriting from one abstract superclass?
- Subject: Re: Multiple EO classes inheriting from one abstract superclass?
- From: David Avendasora <email@hidden>
- Date: Thu, 6 Aug 2009 17:29:17 -0400
On Aug 6, 2009, at 4:10 PM, Andrew R. Kinnie wrote:
Greetings:
I have four tables in a database, which are materialized views from
an oracle db. All four share 12 columns, which are basically
numerical values.
I have 4 components which display repetitions based on these four
tables. I have these inheriting from one abstract superclass
containing the calculations on the 12 values.
It seemed to me logical, and very object oriented to have these 4 eo
tables inherit from 1 abstract superclass containing the 12 shared
attributes.
I modeled this and checked the "Abstract" checkbox in Entity
Modeler. I did not select a source table as this class is supposed
to be abstract.
The problem is, Entity Modeler wants me to have a primary key for
the abstract eo superclass, but the 4 subclasses have different
primary keys representing different foreign keys from their source
tables. Some of these keys are multiple foreign keys from multiple
source tables (i.e. the eo is essentially a join)
If I let Entity Modeler set a primary key of "id" and delete the
inherited "id" primary keys from the subclasses (leaving the
previously existing primary keys, just pointing the subclass eos to
the new superclass), I get an SQL error because the tables are
missing an id column.
Any ideas? It there a way to do this? Or do I need to write the
code 4 times in both the component and the eos?
Hey Andrew,
I thought about this on the way home today, and I think this is a case
of while they appear to be subclasses, they are indeed separate
classes just with several attributes (all but the PK) in that are the
same. This is pretty odd from an OO-point-of-view, but it is taking a
view to coerce the actual tables into something seemingly related in
the first place.
Unfortunately it looks like you will be duplicating the code in
several places, unfortunately. :-(
Dave
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