I suspected that something like that was a possibility. If that is the 
case, then you may as well use one of the binary types, because using 
JAVA_OBJECT doesn't get you anything at all.

On Wednesday, October 2, 2002, at 07:21  PM, Michael Bartmann wrote:

> Stephen Coy wrote:
>
>> Hi,
>>
>> Currently, if the jdbctype of a database column is one of the above 
>> types, the data is explicitly serialized by JBoss 3.x.
>>
>> I've been researching this over the last few days and it seems to me 
>> that the materialisation/dematerialisation of these types is really 
>> in the domain of the JDBC drivers, and should be accessed using the 
>> various set/getObject calls only.
>
> I had problems with that approach when the following conditions all 
> were true
> - I used ear-scoped classloading.
> - the JDBC driver was loaded outside (even before creation of) the 
> ear-scope (Which is the case for CMP).
> - the classes of the objects to be deserialized were not available 
> outside the ear-scope.
> - the JDBC-driver even if invoked in a thread from the ear-scope did 
> not honour the TCL.
>
> This obviously failed. We must consider this when delegating work to 
> the JDBC driver
>
> Just my 2Cent,
> Michael Bartmann
>
>>
>>
>> If the application programmer wants/needs to have their data 
>> explicitly serialised, then they should elect to use one of the 
>> binary jdbc types.
>>
>> The presence of the STRUCT type seems pointless at the moment, 
>> because java.sql.Struct is not serialisable and there is no method of 
>> mapping its content to an EJB attribute,  although we could probably 
>> do some clever stuff with it later.
>>
>> The use of STRUCT and JAVA_OBJECT is often coupled with the use of a 
>> DBMS's abstract datatype system. Oracle, for example, needs to be 
>> able to map JAVA_OBJECT to a type previously defined in the schema. 
>> It does not permit, for example, a JAVA_OBJECT to be stored in a BLOB 
>> column or a RAW(n) column.
>>
>> I want to remove STRUCT altogether, and remove JAVA_OBJECT and OTHER 
>> from the "binary data types" umbrella. At the moment, it's hidden the 
>> fact that hsqldb mappings are missing for java.math.BigDecimal, 
>> java.sql.Time and java.sql.Date - they just get serialised out as 
>> binary data.
>>
>> -----
>> Steve Coy



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