Re: Need to determine which version of a file a program has to work with

On 3/4/11 10:54 AM, Charles Wilt wrote:

I've got a need for a program that can work on two different
versions of a file. Specifically, in one version of the file a
particular field is 10a, in the other it's 7p00.

The program will be using SQL, so level checks aren't an issue. But
I still need to know which version I'm dealing with so I know which
statement to run.

We've come up with the following methods to determine which version
of the field is available
1) IBM API's

Already using SQL, so why go to a non-SQL API? I actually had long ago written a ColumnExists procedure to resolve similar [the old TABLE was missing the field] for a utility upgrade\conversion, using the List Fields (QUSLFLD) API. As I recall the biggest negative for me was that the API was one of those requiring User Space APIs versus allocated storage; i.e. creating a named object that is either remains in QTEMP for reuse or is deleted each time, and for what value.?

2) SQL Describe

Already using SQL, seems good to go. No external *UsrSpc as storage location. If there is a prepared statement with the column, consider describing the statement instead of the TABLE when that might be better to limit the data.

3) Looking at SYSCOLUMNS

Why run a query?

Any pros/cons to the above?

Does anybody have any additional ideas?

Perhaps... Is there really any requirement to know the difference? There is implicit casting between the two types, and explicit casing is legitimate to get a consistent type into the non-SQL program variables.

Regards, Chuck