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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