Steve Nelson
Jamie Jackson wrote:
> Say I've modeled the inheritance in this manner (table per class):
> http://www.agiledata.org/essays/mappingObjects.html#MapEachClassTo
> able
>
> I'm having a tough time figuring out how to join a (subclass's) table
> whose name comes from a column value.
>
> Assuming this is the right way to go about it, how would I join the
> Person superclass to the Employee subclass?
>
> Person
> ------------------------------------------
> ID Name Type
> 1 Jamie Jackson Employee <-- used in join
> ------------------------------------------
>
> Employee
> ------------------------------------------
> ID Salary
> 1 1000000.00
> ------------------------------------------
>
> I can't just do...
> SELECT t1.Name, t2.Salary
> FROM Person t1 LEFT JOIN Employee t2 t1.Id = t2.Id
> WHERE t1.ID = 1 ^^^^^^^^
> ... Since I don't know the ("Employee") table name until after a
> query.
>
> Is there a SQL (preferably vanilla) trick to doing this dynamic join
> in a single query, or do I have to use multiple queries (or sprocs)?
>
> Alternatively, should I wimp out and use views (which would likely be
> reused for reporting)?
>
> Thanks,
> Jamie
>
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