Re: [OJB-developers] EqualToColumnCriteria an Aliases

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

Hi Jakob,

On Saturday 18 May 2002 10:09, Jakob Braeuchi wrote:
> > the column name translation should be performed only in SqlStatment and
> > SqlGenerator. Do you agree?
>
> definitely yes.
>
> EqualToColumnCriteria is a special case because it explicetely uses the
> column name (_not_ the field name) on the right side of  =.
> this column name should imho not be translated.
> i'm not shure about the left side of =. if EqualToColumnCriteria is only
> used in MtoNCriteria we could leave the column names on both sides
> untranslated.
1) EqualToColumnCriteria can be created without MtoNCriteria via 
Criteria.addEqualToColumn(). In this case I believe that the field name 
should be used rather than column name, user shouldn't use column names in 
Java code at all, they should appear once in repository.xml.
I agree with you that such method should be named addEqualToField rather that 
addEqualToColumn. 
BTW, why there is no addGreaterThanColumn method, and so on?

2) I believe that MtoNCriteria should be refactored, maybe even removed, but 
I haven't looked into this issue deeply yet. SqlStatement is able to handle 
M:N relations and there are testcases showing that, so there is absolutely 
no need to do this work twice and to introduce MtoNCriteria for that, and 
then to process MtoNCriteria as a very special case in SqlStatement.

> what we definitely need to translate is an optional table name (ie.
> T_PERSON.FNAME ) here T_PERSON should be replaced by the alias leading to
> A0.FNAME.
There is no 1:1 mapping between table names and aliases, one table may appear 
several times with different aliases.

Regards,
 Oleg