AW: [OJB-developers] Let's fix the testsuite!

[Mahler T. <tho...@it...>]

Hi Oleg,

> -----Ursprungliche Nachricht-----
> Von: =D0=ED=E5=FA =CF=EA=E7 [mailto:on...@uk...]
> Gesendet: Mittwoch, 29. Mai 2002 10:42
> An: obj...@so...
> Betreff: Re: [OJB-developers] Let's fix the testsuite!
>=20
>=20
> Hi Thomas,
>=20
> I am afraid I was not clear enough, actually I proposed two=20
> alternatives, and you commented only the first one, see below.
>=20

sorry, I missed that it were two separate suggestions.

> -----Original Message-----
> From: Thomas Mahler <tho...@ho...>
> To: Oleg Nitz <on...@uk...>
> Date: Tue, 28 May 2002 23:05:59 +0200
> Subject: Re: AW: [OJB-developers] Let's fix the testsuite!
>=20
> > > I see. To achieve this we should either=20
>=20
> 1)
> > > remember the original state of the m:n relation=20
> You commented this one, and I agree that it requires locks.
>=20
> > > or=20
>=20
> 2)
> > > to read the set of all indirection instances from the=20
> > > database in storeMtoNImplementor(), then compare them against=20
> > > the current set of indirection instances in memory,=20
> > > then insert/delete the two differences of two sets.=20
> > > Then there is no need in multiple database lookups.
> This approach is almost as simple as yours.
> First we execute=20
> SELECT fk_for_items FROM indirect_table WHERE fk_for_this=3D?
> and put then into the set1
> The identities for the current m:n collection we put into set2
> Then we calculate "set1 minus set2" and DELETE  these records
> Then we calculate "set2 minus set1" and INSERT  these records
>=20

I agree, this is also quite simple and will eliminate superfluous =
DELETEs !
This is even better than my idea.

cheers,

Thomas

> > A much simpler aproach:
> > before inserting entries for a given relation in=20
> storeMtoNImplementor(),=20
> > just delete all existing entries.
> > This way we
> > - can avoid exception caused by failing inserts,
> > - won't need to track object state to detect removed entries.
> > Overhead should be rather small we'll need to execute only=20
> one DELETE=20
> > statement.
> You are right, we need to execute only one DELETE statement,=20
> but every time we will execute 1 DELETE and many INSERTs,=20
> even if nothing changed.
> With my 2nd approach we will execute 1 SELECT and the number=20
> of DELETEs and INSERTs that is really necessary, i.e. zero if=20
> nothing changed.
> And in general this approach seems more careful :)
> Do you agree?
>=20
> Oleg
>=20
> _______________________________________________________________
>=20
> Don't miss the 2002 Sprint PCS Application Developer's Conference
> August 25-28 in Las Vegas -- =
http://devcon.sprintpcs.com/adp/index.cfm
>=20
> _______________________________________________
> Objectbridge-developers mailing list
> Obj...@li...
> https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
>=20