Indicator variables

An indicator variable is a 2-byte integer (short int). An indicator variable array is an array of 2-byte integers (short int). You use indicator variables and indicator variable arrays in similar ways.

Using indicator variables: If you provide an indicator variable for the variable X, when DB2 retrieves a null value for X, it puts a negative value in the indicator variable and does not update X. Your program should check the indicator variable before using X. If the indicator variable is negative, you know that X is null and any value you find in X is irrelevant.

When your program uses X to assign a null value to a column, the program should set the indicator variable to a negative number. DB2 then assigns a null value to the column and ignores any value in X.

Example:

/* Declaration*/
EXEC SQL BEGIN DECLARE SECTION;
char ClsCd[8];
char Bgn[9];
char End[9];
short Day, DayInd, BgnInd, EndInd;
EXEC SQL END DECLARE SECTION;

EXEC SQL FETCH CLS_CURSOR INTO :ClsCd,
:Day :DayInd,
:Bgn :BgnInd,
:End :EndInd;