[OJB-developers] Re: SqlStatement

[Oleg N. <on...@uk...>]

Hi Jakob,

On Thursday 16 May 2002 08:52, Jakob Braeuchi wrote:
> i have a problem with ms-access (to support it is an ojb feature) and joins
> using the current version of SqlStatement.
>
> SELECT DISTINCT A0.id,A0.idPerson,A0.nummer,A0.saldo FROM tabKonto A0 INNER
> JOIN tabPerson A1 ON A0.idPerson=A1.id INNER JOIN tabTelefon A2 ON
> A1.id=A2.idPerson WHERE (A0.saldo>?) AND A2.tel_nr LIKE ?
>
> this is perfect for mysql but ms-access needs ( ) around nested joins :
>
> SELECT DISTINCT A0.id,A0.idPerson,A0.nummer,A0.saldo FROM (tabKonto A0
> INNER JOIN tabPerson A1 ON A0.idPerson=A1.id) INNER JOIN tabTelefon A2 ON
> A1.id=A2.idPerson WHERE (A0.saldo>?) AND A2.tel_nr LIKE ?
>
> i've attached a fixed SqlStatement that works with mysql and ms-access, but
> i've NOT tested it with hsql and others.
> could you please have a look at it ?
The way you insert parenthesis doesn't look natural for me, 
it doesn't express the tree structure of joins :)
I'd prefer to return to the original way and to use join syntax without 
parenthesis for HSQL and MySQL only. 
I've committed my verion. Please, let me know what you think.

> when tryinig to understand your code, i saw that you make heavy use of
> instance variables.
> this is undoubtably perfect for performance, but i think it will complicate
> future refactorings.
> i prefer parameter passing (ie: for stmt in appendTableWithJoins()  ).
I agree, actually I usually prefer to use parameter passing and I tell to 
others the same things that you told to me :)
And BTW I am not sure that instance variables are better for performance :)
I just tried to make the source code as simple as possible.
I will remove several instance variables.

Thanks,
 Oleg