Using indicator variables with host input variables

When you associate an indicator variable with an input variable, you must explicitly set the indicator variable, using the values in Table 4-3 as a guide.

**Table 4-3: Indicator variable values used with input variable**
Value	Meaning
-1	Treat the corresponding input as a null value.
0	Assign the value of the host variable to the column.

You must supply host language code to test for a null input value and set the indicator variable to -1. This informs Client-Library of a null value. When you set the indicator variable to -1, null is used regardless of the host variable’s actual value.

The following example demonstrates associating an indicator variable with an input variable. The database royalty column is set to a null value because indic is set to -1. Changing the value of indic changes the value of royalty.

exec sql begin declare section;

 CS_SMALLINT     indic;

 CS_INT          royalty;

 exec sql end declare section;

 indic = -1;

 exec sql update titles set royalty = :royalty

     :indic where pub_id = "0736";