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From Jakob Braeuchi <jbraeu...@gmx.ch>
Subject Re: Proposal to support ESCAPE for Like-Criteria
Date Sat, 21 Feb 2004 19:44:17 GMT
hi antonio,

Antonio Gallardo wrote:

> Larry Streepy dijo:
> 
>>Certainly, the Platform interface would have to be extended, and I know
>>that's a pain.  But, it is the most "correct" solution.
> 
> 
> +1
> 
> OJB also abstract the DB Engine. I guess, because currently we don't need
> to care about the specific SQL syntax of the DB Engine we use. Also I

that's only true as long as we stick to 'standard' features :(

> believe we can "magically" switch from one database to another just by
> changing the <jdbc-connection-descriptor>. If OJB will allow some specific
> DB Engine dependencies, then we will lose this nice feature of OJB.

that's what it already does. you can use any dbms-specific function in a where 
clause and ojb will just pass it to the dbms.

jakob
> 
> I think the best we can do is to extend the specific MS Acces classes to
> "convert" as requiered to follow the current OJB approach.
>
> Best Regards,
> 
> Antonio Gallardo
> 
> 
> 
>>Thanks,
>>Larry.
>>
>>
>>>-----Original Message-----
>>>From: Michael Mogley [mailto:mmogley@adelphia.net]
>>>Sent: Saturday, February 21, 2004 9:38 AM
>>>To: OJB Developers List
>>>Subject: Re: Proposal to support ESCAPE for Like-Criteria
>>>
>>>I was just thinking the same thing.  My understanding is the Platform
>>>interface was created to solve just this type of problem.  Though it
>>>doesn't
>>>currently have a method to get the escape character.
>>>
>>>Michael
>>>
>>>----- Original Message -----
>>>From: "Larry Streepy" <larry@staffmix.com>
>>>To: "'OJB Developers List'" <ojb-dev@db.apache.org>
>>>Sent: Saturday, February 21, 2004 9:29 AM
>>>Subject: RE: Proposal to support ESCAPE for Like-Criteria
>>>
>>>
>>>
>>>>I would argue that specialized handling of the wildcard characters
>>>
>>>belongs
>>>
>>>>in the DB-specific classes.  One of the goals (at least in my mind) is
>>>
>>>that
>>>
>>>>OJB makes it fairly easy to move between database platforms without
>>>
>>>massive
>>>
>>>>changes to your application.  The proposal below breaks that paradigm
>>>
>>>by
>>>
>>>>requiring DB-specific handling for something as simple as wildcard
>>>
>>>handling.
>>>
>>>>I know I get no real vote, but take this as a plea to move this
>>>
>>>handling
>>>
>>>>into the DB-specific layers.
>>>>
>>>>Thanks.
>>>>Larry.
>>>>
>>>>
>>>>
>>>>>-----Original Message-----
>>>>>From: Jakob Braeuchi [mailto:jbraeuchi@gmx.ch]
>>>>>Sent: Saturday, February 21, 2004 6:44 AM
>>>>>To: OJB Developers List; Nase.Paul@mayo.edu
>>>>>Subject: Proposal to support ESCAPE for Like-Criteria
>>>>>
>>>>>hi all,
>>>>>
>>>>>i had a long discussion with paul r. nase about like criteria
>>>
>>>containing
>>>
>>>>>escaped
>>>>>wildcards (example: first name like 'h%\%' escape '\' looks for
>>>
>>>firstname
>>>
>>>>>starting with 'h' and ending with '%'). for details see:
>>>>>
>>>>>  http://article.gmane.org/gmane.comp.jakarta.ojb.user/12505
>>>>>
>>>>>ojb currently does not properly support escaping of wildcards. while
>>>>>experimenting with this feature i found that we have some dbms-
>>>
>>>dependent
>>>
>>>>>problems:
>>>>>
>>>>>1.) escape character \ is the default in mysql so escape '\' is not
>>>>>accepted.
>>>>>we'd need '\\'
>>>>>2.) replacing wildcards *, ? by %, _ does not work for ms-access.
>>>>>3.) escaping wildcards is different in ms-access
>>>>>
>>>>>so i propose to use a manual escaping in like-criteria without
>>>
>>>replacing
>>>
>>>
>>>>>wildcards. the user will have to provide the escape clause for the
>>>
>>>like-
>>>
>>>>>criteria:
>>>>>
>>>>>addLike(attribute, criteria, escapeClause);
>>>>>ie:
>>>>>addLike("firstname", "h%\\%", "escape '\\'");
>>>>>
>>>>>ms_access: addLike("firstname", "h*[*]");
>>>>>
>>>>>the escape clause will be appended to the like-clause when building
>>>
>>>the
>>>
>>>>>sql.
>>>>>i'll implement a dedicated LikeCriteria to support escaping.
>>>>>
>>>>>what do you think about this ?
>>>>>
>>>>>jakob
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>
>>>>
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>>>>
>>>
>>>
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>>
>>
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>>
> 
> 
> 
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