what is database command?

When user log on to the teradata system he is placed in a database ,
which is used while creating the user.

To access objects in this database , he can access by using name

If wants to access objects in other databases then he has
to prefix object name with database name.

Instead of doing that , he can use database command to change into
a particular database and access all objects by their names.

Syntax : database ;

Ex: database salesdb;