I have also been using Dieter's routines, but only for running quick
queries under STRSQL.
for this I would recommend SQuirreL (running on Windows or Linux), it's Freeware and JDBC based and could connect to Oracle and AS/400 (some sort of WebQuery, but it works!) and has very nice features (generating Scripts, copying Tables cross systems...)
I have found JDBCR4 a little easier to use, as I have more control over the
data types (Everything is char, and I get to decide what to convert it to).
SAP/Oracle data can be a little pain to process. Many of the numeric
data are stored as Varchar, and there are also some DB2 incompatible data
This would be no problem with ArdGate too, just cast the columns to what ever you want in your SQL statement running against oracle. For conversion purposes you could cast to char and reuse quite a lot of your code. But I would recommend to do the needed conversions with the SQL statement.