RE: RPG, RPG400, & SQL

[jpcarr@xxxxxxxxxxxx]

Like Buck said;

Checking for *Null is like

Something like the bathroom on an Airplane.   You don't open the door to
see what/who is in there(is it occupied),
You look at the little sign on the OutSide of the door to know it it is
empty(*NULL) or not.

As Buck said,  It's an attribute of the field,  Nothing to do with the
contents.

D    SalesNull S    4B 0
C/Exec SQL
    C+             Select CustId,
    C+                        CustNam,
    C+                        CustSales
    C+             Into:   :DSCustId,
    C+                        :DSCustName,
    C+                        :DSCustSales :SalesNull
    C+             From Customer  Where CustId = 'ACME'
    C/End-Exec

In this example CustSales is Null capable.  You read the field into your
host variable and read in the flag(SalesNull) into a 4B field.
Check the SalesNull variable to see if it is has a value of -1.
If so then field DSCustSales is *NULL


John


Eric said something that bears repeating:
*NULL is not a value.  It is an attribute.

An amount field can contain 12.95 AND be *NULL at the same time.
You need to check for nullness before you use the field.