Class structure is something like this..
+------+ +------------+ +-------------+
| Bar |--------o| Relation |o - - - - - - | Foo |abstract
+------+ +------------+ +-------------+class
| id | | attrs |o | id |
| name | +------------+ \_________ | name |
+------+ \ \ +-------------+
\ \___^_____ ^
\ | \ |
\ +------------+ +-------------+
\| NoisyFoo | | ColouredFoo |
+------------+ +-------------+
| id | | id |
| decibels | | color |
+------------+ +-------------+
Bar has many Relations
NoisyFoo has many Relations
ColouredFoo has many Relations
Bar many-many NoisyFoos
Bar many-many ColouredFoos
(Bar many-many Foos?)
NoisyFoo and ColouredFoo inherit from Foo
It actually gets more complicated than this because
- Bar and Foo both inherit from a base object.
- All objects have a unique id are connected via Relation objects
- The relation object also contains levels of inheritance
I want to be able to do queries like
1) Given a Bar, find all related Foo objs
2) Given a NoisyFoo or Coloured Foo, find all related Bars
3) For all bars with name matching "%str%" find all NoisyFoos with decibels >
'100'
Im not sure whether it would be better to
a) retain Foo, NoisyFoo and ColouredFoo as a 3 separate tables,
b) flatten to 2 tables, so NoisyFoo and ColouredFoo get their own name column
c) flatten all Foos to 1 Foo table and create a Type column to differentiate.
Questions:
Is it possible to create Foo, NoisyFoo and ColouredFoo as separate tables (a),
then create corresponding DBIx proxy classes for them in such a way that when I
create a new NoisyFoo row, the 'name' value is automatically entered into the
Foo table? And when I retrieve the row it is automatically read in from the Foo
table?
If I were to flatten to 1 table per subclass (b), how would I write a
relationship that enabled me to perform query (1) above; find all Foos for a
given Bar.
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