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From Bill Leng <wl...@metatomix.com>
Subject Re: Toruqe supports BLOB ????
Date Mon, 04 Aug 2003 18:02:31 GMT
Add to Geoff's comment. It is confirmed that it works with datadirect's 
jdbc driver for Oracle. Oracle's thin jdbc driver does not work.

Geoff Fortytwo wrote:

> If you're using oracle than it isn't possible to use blobs with torque. 
> (except possibly if you use a driver that's not from Oracle. but that 
> isn't confirmed)
> 
> At 10:40 AM 8/4/2003, you wrote:
> 
>> Dear List and Torque Developers,
>>
>> Not much activity on this list is there??  :)
>>
>> The http://db.apache.org/torque/dtd/database_3_1.dtd  indicates that BLOB
>> are a valid torque data type.
>>
>> It possible to save an image to a blob with the current version ? Could
>> someone give a small example. We have done this using BC4J and with 
>> JDBC on
>> its own, does the current version of torque help me?
>>
>> Kind regards,
>>
>>
>> Ben bookey.
>>
>>
>> ----- Original Message -----
>> From: "Michel Beijlevelt / Lucka" <mbe@lucka.nl>
>> To: "Apache Torque Users List" <torque-user@db.apache.org>
>> Sent: Monday, August 04, 2003 2:42 PM
>> Subject: Re: different internal variable names
>>
>>
>> > Howdy,
>> >
>> > the opinion about  tight or loose coupling is also influenced by the
>> > frequency of changes in the RDBMS schema.
>> >
>> > If my application is - through Torque - tightly coupled with the RDBMS,
>> > it will almost certainly fail with an exception upon a moderately
>> > significant change in the RDBMS. Which is good, because it will
>> > precisely pinpoint the change, and makes 'sure' (well, fairly sure that
>> > is :-) that my appliction only runs against the RDBMS that is was
>> > designed for and none other.
>> >
>> > But I agree, having the possibility of  making Torque more loosely
>> > coupled from the RDBMS would be a nice feature. It could be implemented
>> > by allowing specifying aliases for db objects in the XML schema
>> > definition which does seem to be fairly simple to implement, but 
>> maybe a
>> > more sophisticated abstraction layer isn't that hard to make either.
>> >
>> > gr. Michel
>> >
>> >
>> > Manske, Michael wrote:
>> >
>> > >hi,
>> > >
>> > >i knew that such a discussion would come up and it depends on the 
>> point
>> of
>> > >view of each indivual user. :)
>> > >
>> > >
>> > >
>> > >>I don't know, I think I would Torque rather see more tightly coupled
>> > >>with the RDBMS and dump the XML schema entirely.
>> > >>
>> > >>
>> > >if you have control over database structure and changes of the 
>> database
>> > >structure, then you will
>> > >perhaps prefer a strict coupling. But if not (like me), you will 
>> always
>> > >prefer loose coupling to be more independent of changes made by 
>> another
>> dev
>> > >team.
>> > >
>> > >
>> > >
>> > >>My RDBMS already has a schema, which would be the metadatabase in the
>> > >>systems tables. So why create another definition in XML of the same
>> > >>database and tables?
>> > >>
>> > >>
>> > >If you have to support different RDBMS the metadescription in some
>> "system
>> > >tables" will get useless.
>> > >
>> > >
>> > >
>> > >>Torque's capability of abstraction of the RDBMS-specific
>> > >>isssues comes
>> > >>in quite handy here. The process could be automated by having Torque
>> > >>generate the XML definition from a JDBC conncection, and then
>> > >>generate
>> > >>the om from that XML, but I haven't tried that yet.
>> > >>
>> > >>
>> > >Thats what i'm talking about, we are working with torque this way 
>> because
>> we
>> > >have to deal
>> > >with a couple of already existing databases.
>> > >And yes, torques abstraction is somewhat of handy - thats why we 
>> use it.
>> :-)
>> > >
>> > >Loose coupling means among other things to hide the physical database
>> > >structure completely from the objects, which have to access the 
>> database.
>> A
>> > >layer (like torque) will then act as mediator between objects and
>> database.
>> > >So if you would have problematic identifiers like "short", you 
>> would be
>> > >easily able to map them to another name, which could then be used 
>> in java
>> > >objects, e.g. map "short" to "short_descr".
>> > >There is already some kind of support for this but at the moment it 
>> isn't
>> > >suitable at all.
>> > >
>> > >I guess torque is so popular because of his abilities to generate 
>> more or
>> > >less useable code and the usage of a xml schema at runtime 
>> (respectively
>> at
>> > >application startup) would possibly be contradictory to the 
>> generator BUT
>> it
>> > >would also provide more independency from used database structure.
>> > >
>> > >I'm not sure wheter this is a mainly intention of torque but i 
>> would be
>> glad
>> > >if the devs would expand
>> > >support for loose coupling (at least for mapping of table/column 
>> names to
>> > >java names) in future versions...
>> > >
>> > >regards,
>> > >Michael
>> > >
>> > >PS: pros and cons of loose coupling will always be a matter of opinion
>> > >
>> >
>> >
>> >
>> > ---------------------------------------------------------------------
>> > To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
>> > For additional commands, e-mail: torque-user-help@db.apache.org
>> >
>> >
>>
>>
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> 
> 
> 
> ---------------------------------------------------------------------
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-- 
Bill Leng
Metatomix, Inc.
Tel: (901)261-8911
Fax: (901)261-8901


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