The results of a migration D6+ADO+MS.SS => D6+ADO+Oracle

On my request for help concerning backend migration from MS SQL Server to Oracle (see article 3513: D6+ADO+MS.SS => D6+ADO+Oracle ????) I received just one reaction from Bob Dole. Bob told me 'If you've kept your design SQL-92 compliant, everything should work fine'.

I went to my client (7000 Km away!) expecting only some problems with date fields. However .....

Oracle before version 9i is not SQL-92 compliant at all. Oracle does not support the join syntax, but uses a funny notation with a plus sign in the WHERE condition. The Oracle guys did their job so mediocre, that they did not even enable the parser to adapt SQL-92 syntax to their own the funny notation.

In Oracle 9i the product has grown up a bit and joins are now SQL-92 compliant.

The second problem was, that Oracle - including Oracle 9i - does not know the integer datatype. Of course you can use number, but you can bet, that you will have situations where you have to change your source because the presence of a decimal point is a problem.

For the rest ( that is after convincing my client, that there Oracle 8 software should be upgraded to Oracle 9i and after changing all the integer fields into number fields (also in the MS SQL server database, because I want to maintain a single version ) my app did run smoothly on bothe backends.

However, if I get a new client who is not willing to switch to 9i I have to rewrite all my SQL-joins in that funny Oracle style (what idiot did invent this notation?) and have a switch for using the funny SQL Select when Oracle < 9i is the backend and the SQL 92 compliant Select otherwise.  

I hope this story helps people who plan to design software for MS SQL Server and Oracle using ADO.