Aliases

An alias is a substitute for the three-part name of a table or view.

An alias can be defined at a local server and can refer to a table or view that is at the current server or a remote server. The alias name can be used wherever the table name or view name can be used to refer to the table or view in an SQL statement.

Suppose that data is occasionally moved from one Db2 subsystem to another. Ideally, users who query that data are not affected when this activity occurs. They always want to log on to the same system and access the same table or view, regardless of where the data resides. You can achieve this result by using an alias for an object name.

An alias can be a maximum of 128 characters, qualified by an owner ID. You use the CREATE ALIAS and DROP ALIAS statements to manage aliases.

Begin general-use programming interface information.

For example, assume that you create an alias with the following statement:

CREATE ALIAS TESTTAB FOR USIBMSTODB22.IDEMP01.EMP;

If a user with the ID JONES dynamically creates the alias, JONES owns the alias, and you query the table like this:

SELECT SUM(SALARY), SUM(BONUS), SUM(COMM)
  FROM JONES.TESTTAB;

End general-use programming interface information.

The object for which you are defining an alias does not need to exist when you execute the CREATE ALIAS statement. However, the object must exist when a statement that refers to the alias executes.

When you want an application to access a server other than the server that is specified by a location name, you do not need to change the location name. Instead, you can use a location alias to override the location name that an application uses to access a server. As a result, a Db2 for z/OS® requester can access multiple Db2 databases that have the same name but different network addresses. Location aliases allow easier migration to a Db2 server and minimize application changes.

After you create an alias, anyone who has authority over the object that the alias is referencing can use that alias. A user does not need a separate privilege to use the alias.