n is either 1 or 0. The default value is 0.
When DDLNo311 is enabled (n = 1), when an attempt is made to ADD a foreign key, even if a key of that name already exists, InterSystems IRIS® data platform suppresses the SQLCODE -311 error.
For further details, refer to the ALTER TABLE command.
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 DDLNo311 with the Config.SQLOpens in a new window 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).