Aliases
An alias is an alternative name for an object such as a module, table or another alias. It can be used to reference an object wherever that object can be referenced directly.
An alias cannot be used in all contexts; for example, it cannot be used in the check condition of a check constraint. An alias cannot reference a declared temporary table but it can reference a created temporary table.
Like other objects, an alias can be created, dropped, and have comments associated with it. Aliases can refer to other aliases in a process called chaining as long as there are no circular references. Aliases do not require any special authority or privilege to use them. Access to the object referred to by an alias, however, does require the authorization associated with that object.
If an alias is defined as a public alias, it can be referenced by its unqualified name without any impact from the current default schema name. It can also be referenced using the qualifier SYSPUBLIC. Public aliases can be used only in SQL statements and with the LOAD utility.
Synonym is an alternative name for alias.
For more information, refer to Aliases for database objects.