[Engine-devel] Introduce a change to oVirt-engine-core DB

[Mike Kolesnik]

----- Original Message -----
> On 11/15/2011 07:20 AM, Itamar Heim wrote:
> > On 11/15/2011 10:15 AM, Mike Kolesnik wrote:
> >>
> >> In this method, "single table inheritance", the fields which are
> >> not
> >> in the base type are still kept in the same table. This way you
> >> gain
> >> simplicity and order in the DB, while you give up constraints
> >> which
> >> need to be kept at the logic level. It's a tradeoff which I think
> >> would be good in this case, since the amount of different fields
> >> is
> >> small.
> >>
> >> The differnet types simply map to certain fields that they need,
> >> much
> >> like a view on the table.
> >>
> >>>
> >>> looking at the fields different right now, i think a single table
> >>> would
> >>> be fine. in the future splitting entity specific fields could be
> >>> revisited.
> >>>
> >>
> >> Of course this whole thing can be undone without much work if
> >> somewhere along the road we deicde that it wasn't a good idea.
> >
> > doesn't have to be undone. you could also just spin off the columns
> > which aren't shared by the two entities.
> > anyway - i think we are agreeing
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> What problem is this attempting to solve?  I understand that it is
> not
> aesthetically pleasing to have the two split out but unless this is
> causing undue complexity in the code (which doesn't seem to be the
> case
> due to the abstractions) is causing performance problems or is making
> further development difficult I'm tempted to say leave it as it is.

The main benefit I see is keeping it DRY.
This will help us manage the DB structure more easily (less tables and mapping tables which all just duplicate each other).
I don't think this change is something that heavy that it's not worth doing, and for me keeping it DRY is an advantage, just as you would refactor code to do the same.

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Regards,
Mike