2013/10/16 Peter Cooner <[email protected]>
>
> On Wed, Oct 16, 2013 at 3:17 AM, Lukas Eder <[email protected]> wrote:
>
>>
>>
>> 2013/10/15 Peter Cooner <[email protected]>
>>
>>> Honestly PG inheritance was pretty bad in 8.X, and only started to rock
>>> in 9.X, I'm thinking there isn't a lot of real multiple inheritance in use
>>> out there (that doesn't mean there won't be of course).
>>>
>>
>> Well, a good use case that I could see is to define something mixin types
>> for very common attribute sets, such as DATE_CREATED, DATE_MODIFIED,
>> USER_CREATED, USER_MODIFIED. Such attributes could be declared in a base
>> table / type and then inherited by all relevant tables, which can also
>> inherit from other structures. I'm not particularly experienced with such
>> an ORDBMS way of thinking, but it would certainly be interesting to
>> experiment with that.
>>
>
>
> Hah. Yesterday I accidentally a word. I meant to write "Honestly PG
> inheritance performance was pretty bad in 8.X". Sorry about that.
>
Between the lines, I was actually reading precisely that :-)
> I think you've made an excellent example.
>
> And when I was working in JOOQ on my own inherited tables, I really wanted
> to be able to to do things such as:
>
> Result<BaseRecord> results;
> results = create.selectFrom(Tables.CHILD_TABLE)....
>
> or
>
> BaseRecord br = .... ChildTable ...
>
> But I got over all that pretty quickly because I realized that usually
> what I really needed to do was to push data (or type) from ChildRecord into
> a BaseRecord or from ChildA into ChildB which had the same columns.
>
> Besides that the table classes generated already extend a class so I think
> a different solution is in order.
>
> Which brings me back to mapping...
>
>
>
>> Anyway, I'm wondering if maybe some of those mapping functions in JOOQ
>>> couldn't be the best solution? My brain is fuzzy on the topic, but aren't
>>> the values are kept in a store, might there be a "fast" way to map between
>>> one table type and another? Maybe some sort of internal JOOQ table hinting
>>> would allow for quicker mapping, or re-typing as the case might be...
>>>
>>
>> What do you mean by "those mapping functions" ?
>>
>
> Ah yes, I meant on a result set there are the map() and into(Table<R>)
> functions which map data from one to another.
>
> I guess the point of all this was to say that I can't see a good way for
> JOOQ to do this within the Java type system, so maybe a good helper is more
> useful then a perfect type-safe solution?
>
Hmm, you mean like generating "helper" methods such as:
public class ParentTableRecord {
public ChildTableRecord intoChildTable() {
return into(CHILD_TABLE);
}
}
public class ChildTableRecord {
public ParentTableRecord intoParentTable() {
return into(PARENT_TABLE);
}
}
That would probably be quite useful... I've registered #2782 for this.
https://github.com/jOOQ/jOOQ/issues/2782
Let me know if you see other useful additions.
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