Re: Using BLOBs with several DBMS

> My question is: how can i create a table with one BLOB field, in a DBMS
> independent way?
>
> I am using PostgreSQL7.1 and Oracle 8 but I want to make it be able to work
> with other DBMSs.

It is difficult, because:

* Different versions of SQL use different names for the BLOB type.

* Some DBMS don't support blobs at all.

* Some DBMS treat blobs differently to other SQL types and
require you to use special APIs to access them.

* Not all JDBC drivers support the JDBC 2.0 Blob APIs. Of those
that do, many implement them in part only.

Given this mess, you've got two choices:

* Define a Java interface for all of your database interactions.
Create a different implementation for each DBMS you plan to support,
complete with embedded SQL statements, table schemas, etc.

* Define wrapper classes for JDBC, and try to isolate the DBMS
differences in "adapters". This (more or less) allows you to
share SQL statements / table schemas across DBMS, but it is
kind of hard getting the wrapper / adapter APIs right.

-- Steve