Alter a table column with auto increment by 1 in derby

I have found an alternate solution, i dropped the column from the database (thanks vels4j) added the column once again from the netbeans derby UI as shown below:

To alter the column to be auto-generated, the code is

ALTER TABLE ISSUERECIPT ALTER IRCODE SET INCREMENT BY 1;

BUT the column must already be defined with the IDENTITY attribute (as written in this documentation).

In most cases (assuming that you too), the primary key column is not set as IDENTITY. Therefore, you may intend to alter the column to IDENTITY, but that is impossible.

The only way is to drop the table and create it again, as written here.