|Oracle9i OLAP Developer's Guide to the OLAP DML
Release 2 (9.2)
Part Number A95298-01
Developing Programs, 6 of 12
When an OLAP DML program returns a value, it is called a user-defined function. You can use it in commands and expressions.
A user-defined function contains a
RETURN command followed by an expression.
RETURN command returns a single value when the program terminates.
When you create a user-defined function, you define the program with a data type or dimension name, using the following syntax of the
datatype argument specifies the data type of the value to be returned by the program when it is called as a function.
dimension argument specifies the name of a dimension whose value the program returns when it is called as a function. The return value will be a single value of the dimension, not a position (integer). The dimension must be defined in the same analytic workspace as the program. The value that is returned by the program has the data type that is specified in the definition. If you specify a dimension name, then the program returns a value of that dimension.
The return expression in the program should match the data type that is specified in its definition. If the data type of the return value does not match the data type that is specified in its definition, then the value is converted to the data type in the definition.
If you do not specify a data type for the program, then the return value is converted to the data type that is required by the caller.
User-defined functions can accept arguments. A user-defined function returns only a single value. However, if you supply an argument to a user-defined function in a context that loops over a dimension (for example, in a
REPORT command), then the function returns results with the same dimensions as its argument.
You must declare the arguments using the
ARGUMENT command within the program, and you must specify the arguments in parentheses following the name of the program.
"Passing Arguments" for more information about using arguments with programs.
Suppose your analytic workspace contains a variable called
units.plan, which is dimensioned by the
month dimensions. The variable holds integer data that indicates the number of product units that are expected to be sold.
Suppose also that you define a program named
units_goals_met. This program is a user-defined function. It accepts three dimension-value arguments that specify a given cell of the
units.plan variable, and it accepts a fourth argument that specifies the number of units that were actually sold for that cell. The program returns a Boolean value to the calling program. It returns
YES when the actual figure comes up to within 10 percent of the planned figure; it returns
NO when the actual figure does not.
The definition of the
units_goals_met program is listed below.
DEFINE units_goal_met PROGRAM BOOLEAN LD Tests whether actual units met the planned estimate "Program Initialization ARGUMENT userprod TEXT ARGUMENT userdist TEXT ARGUMENT usermonth TEXT ARGUMENT userunits integer VARIABLE answer boolean TRAP ON errorlabel PUSH product district month "Program Body LIMIT product TO userprod LIMIT district TO userdist LIMIT month TO usermonth IF (units.plan - userunits) / units.plan GT .10 THEN answer = NO ELSE answer = YES "Normal Exit POP product district month RETURN answer "Abnormal Exit errorlabel: POP product district month SIGNAL errorname errortext END
To execute the
units_goal_met program and store the return value in a variable called
success, you can use an assignment statement.