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SQL Anywhere 11.0.1 » UltraLite - C and C++ Programming » Application Development » Developing applications using Embedded SQL » Using host variables


Using indicator variables

An indicator variable is a C variable that holds supplementary information about a particular host variable. You can use a host variable when fetching or putting data. Use indicator variables to handle NULL values.

An indicator variable is a host variable of type short int. To detect or specify a NULL value, place the indicator variable immediately following a regular host variable in a SQL statement.


For example, in the following INSERT statement, :ind_phone is an indicator variable.

   VALUES (:employee_number, :employee_name,
   :employee_initials, :employee_phone:ind_phone );
Indicator variable values

The following table provides a summary of indicator variable usage:

Indicator value Supplying value to database Receiving value from database
0 Host variable value Fetched a non-NULL value.
-1 NULL value Fetched a NULL value

Using indicator variables to handle NULL