Specifying informational constraints on nicknames

To improve the performance of queries on remote data sources, you can add informational constraints to nicknames. However, the federated server does not enforce or check the constraints.

About this task

Restrictions

After you define informational constraints on a nickname, you can only alter the column names for that nickname after you remove the informational constraints.

About this task

For relational data sources, you can specify informational constraints when you alter a nickname.

For non-relational data sources, you can specify informational constraints when you create a nickname or alter a nickname.

Procedure

To specify informational constraints on a nickname from the command line, issue the CREATE NICKNAME statement or the ALTER NICKNAME statement with the appropriate constraint attributes.