When your application attaches to one or more databases, SQL
    associates the databases with a set of aliases (database
    handles). In CONNECT, DISCONNECT, or SET CONNECT statements,
    you refer to this association as the connection name. You can
    specify the connection name as a parameter marker from dynamic
    SQL, a host language variable from a precompiled SQL program,
    a parameter from an SQL module language module, or a string
    literal.

    The set of databases that you can attach or detach as one unit
    is called the database environment. Within an application, all
    of the databases declared in all the modules form the default
    database environment for that application at run time. For more
    information about connections, see the CONNECT.