Hi All,

I've been tasked with writing a z/OS C program to read and update a table
(DB/2 v8).  This Table contains a single row with a single column of data.
This program (which will run as a Stored Proc) needs to implement a strategy
for concurrency as the Stored Proc can be called concurrently by several
different users.

The code essentially does the following:

1) Read the current value (eg. "ABCD")
2) Increment the value to the next value (eg. "ABCE")
3) Write the incremented value back to the table

In my code, I'm doing the following:

EXEC SQL
 DECLARE C2 SENSITIVE STATIC SCROLL CURSOR FOR
   SELECT NEXT_MAILBOX_ID FROM BTMFE_MB_NEXT_AVL
     FOR UPDATE OF NEXT_MAILBOX_ID;

EXEC SQL
 OPEN C2;

EXEC SQL
 FETCH FROM C2
   INTO :OLD_MAILBOXID;

// the next value is calculated here and stored in :NEW_MAILBOXID
// the new value is then written back to the table

EXEC SQL
 UPDATE BTMFE_MB_NEXT_AVL
   SET NEXT_MAILBOX_ID = :NEW_MAILBOXID
     WHERE CURRENT OF C2;

EXEC SQL
 CLOSE C2;

It seems a little overkill to use a Cursor for something so simple, but our
DBA recommended we use one.

Everything works as expected, but I'm not sure if concurrency has been
addressesed.

- Do I need to use a SCROLL cursor when the table only has a single record
with a single column?
- How do I ensure that the row is locked during the above activity?

Sorry for the basic questions, but I'm not a database guy.

Thanks in advance.