n is either 1 or 0. The default value is 0.
When DDLNo307 is enabled (n = 1), when an attempt is made to CREATE a primary key constraint to a table through DDL, and a primary key constraint already exists for that table, InterSystems IRIS® data platform suppresses the SQLCODE -307 error.
Changing This Parameter
On the SQL page of the Management Portal (System Administration > Configuration > SQL and Object Settings > SQL), select Ignore redundant DDL statements to suppress redundant SQLCODE errors.
You can also change DDLNo307 with the Config.SQL class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).