Creating Generators (Embedded SQL Guide)
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A generator is a monotonically increasing or decreasing numeric value that is inserted in a field either directly by a SQL statement in an application or through a trigger. Generators are often used to produce unique values to insert into a column used as a primary key.
To create a generator to use in an application, use the following CREATE GENERATOR
syntax:
EXEC SQL CREATE GENERATOR name;
The following statement creates a generator, EMP_NO_GEN
, to specify a unique employee number:
EXEC SQL CREATE GENERATOR EMP_NO_GEN; EXEC SQL COMMIT;
Once a generator is created, the starting value for a generated number can be specified with SET GENERATOR
. To insert a generated number in a field, use the InterBase library GEN_ID()
function in an assignment statement. For more information about GEN_ID()
, CREATE GENERATOR
, and SET GENERATOR
, see the Data Definition Guide.