Re: Legacy File handling: Switching between files opened read-only and read-write

Hello Darryl,

thanks for your valuable input!


Am 15.04.2020 um 02:53 schrieb DFreinkel <dfreinkel@xxxxxxxxxxxxxxxxx>:

This is confusing
How are you using a ODBC driver in RPG?

I don't. Sorry for being ambiguous. The ODBC-Access to the file(s) is happening from outside the AS/400, from Linux via ODBC.

Are you allocating the files *excl?

How can I tell if I do?

Another way to read a file twice in a rpg program is to use file-a and file-b in the rpg. Rename the record format on the f-spec of one of the files.

Before compiling do a ovrdbf file-b to file-a. Create the pgm interactively to keep the ovrdbf in effect basically the same job.

It should compile.

You can create a cl to compile in batch
- ovrdbf File-b file-a
- crtrpgpgm

Next before running the job
You will need a cl program to
- ovrdbf file-b to file-a
- call your program
-dltovr

Does this do it for you?

Sounds complicated. :-) Honestly, I don't see how this could help. Basically I want to "switch" from read-write to read-only within the RPG program and vice versa, so the table(s) are opened read-write within the Green Screen application for as short as possible, to avoid the locking problem with external ODBC access.

At the moment, I'm using LFs with different file- and record format names pointing to the corresponding PFs. The LFs are opened all the time, while I open the PFs just before DELETE/UPDATE from the Green Screen Application. This is a working solution since the reading routines in RPG are different from the writing ones.

While this basically works, I don't know why this locking issue happens in the first place, and what other, maybe more elegant ways exist to overcome the described issue.

Does this clarify things?

:wq! PoC

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