How Do DataAdapters Handle Output Parameters Correctly

[jehugaleahsa]

Hello:

I am trying to implement a "connected" database library. By connected
I mean that I don't use DataTable anywhere.

What I have noticed is that OracleDataAdapters can somehow map an
output parameter from Oracle and either create a DataReader for
ExecuteReader or a scalar for ExecuteScalar. (In fact, this is the way
I have temporarily gotten it to work in my code).

I was wondering what magic is being used to make this happen.

My guess is that this is Oracle-dependent code. My guess is that, for
the ref cursor, Oracle sees that it is a stored procedure and then
loops through the parameters and chooses the first output/return value
that is a ref cursor. This seems heavy duty.

Moreover, it would seem if there are multiple output parameters and
you are filling a dataset it will generate a reader for each and fill
each table.

Here is another question. I am trying to keep my library as DBMS-
independent as possible. I was wondering how MS SQL and MySQL handle
result sets from stored procedures. Oracle uses ref cursors, for
example.

Thanks!