Question

I would like to create and deploy this function in DB2, but I got stuck. Could you please help me?

Cheers,

My function code:

CREATE FUNCTION getID(NameIn VARCHAR(255),versionIn varchar(255))
 RETURNS varchar(12)
 NOT DETERMINISTIC
 LANGUAGE SQL
 MODIFIES SQL DATA
 NO EXTERNAL ACTION
 BEGIN 
  declare IDOut varchar(12);
  set IDOut = (select mID 
    from mIDHolder 
    where mName = NameIn and version = versionIn);
  IF mappingIDOut IS NULL THEN
    set IDOut = Hex(GENERATE_UNIQUE());
    insert into mIDHolder VALUES (IDOut,NameIn,versionIn);
  END IF;
  RETURN IDOut;
 END

Here is the mIDHolder Table DDL

CREATE TABLE "V"."MIDHOLDER" (
    "MID" VARCHAR(12) FOR SBCS DATA NOT NULL, 
    "MNAME" VARCHAR(255) FOR SBCS DATA WITH DEFAULT NULL, 
    "VERSION" VARCHAR(255) FOR SBCS DATA WITH DEFAULT NULL
)

Answer 1

What version of DB2 for zOS are you using?

Looking at the documentation for CREATE FUNCTION on version 10, it states that MODIFIES SQL DATA is incompatible with ALLOW PARALLEL. And ALLOW PARALLEL is the default when you specify NO EXTERNAL ACTION. I suspect this is your problem.

On the other hand, looking at the documentation for CREATE FUNCTION on version 9.1, I don’t see MODIFIES SQL DATA mentioned as an option anywhere. In fact, if you look at what they say under READS SQL DATA it strongly suggests that statements that modify tables are not allowed in functions at all.

In my experience, function and procedure definitions are terribly finicky, error messages are opaque, and there are big differences between DB2 versions.