Re: No way to ALTER VARIABLE besides CREATE/DROP?

On 16-Dec-2015 21:19 -0600, Justin Dearing wrote:

If I CREATE VARIABLE foo INT DEFAULT 5 it will always be 5 until I do
a SET, but the SET foo = 6; is only scoped to the session.

Yep. But how might one create a variable for which the value is scoped beyond the /session/?

So, its actually not a big deal for my current application because
the variable (a start date for new business rules) should be a
constant, and I'm only going to change it in QA. If the business
rules get delayed, then a CREATE/DROP is fine. However, what if I
had a variable that was a counter of some kind? What if I expected
some job to be constantly changing the value of a global variable
and several other jobs to be periodically SELECT SCHEMA.VARIABLE
FROM SYSIBM.SYSDUMY1? Is DROP/CREATE in a transaction the
appropriate behavior? Is there a risk that the SELECT might occur
when the variable doesn't exist?

Either the term /global/ should be viewed with skepticism, or the perspective of what the term /global/ means relative to /session/ probably needs adjustment; /session/ does not mean inter-process. Global Variable is in some manner, for the ability to share the data, only as similarly /global/ as the Global Temporary Table (GTT). See "Notes" in the CREATE VARIABLE docs:

[https://www.ibm.com/support/knowledgecenter/api/content/ssw_ibm_i_72/db2/rbafzcvariable.htm]
_CREATE VARIABLE_
"The CREATE VARIABLE statement defines a global variable at the application server.
...
_Notes_

_Session scope_: Global variables have a session scope. This means that although they are available to all sessions that are active on the database, their value is private for each session.
..."