Passive routing sessions can access objects on the Teradata systems to which they are routed. It is not necessary to add or manage objects for passive routing sessions. Managed routing sessions can only access objects that are managed on the systems to which they are routed. This means the objects must exist in the Unity data dictionary, which monitors the object definitions and placement.
Under normal operation, Unity automatically maintains the data dictionary. As clients create new objects, the objects are automatically added to the Unity data dictionary. As objects are dropped, they are removed from the data dictionary.
After executing a data dictionary scan to find where an object exists, the DBA must decide on which system to manage the object. The DBA can allow the object to be managed on all the systems on which the object exists or, if the objects are not yet synchronized, only a single system out of the set can be used. Controlling where an object or database is managed can be done using the Unity UI or the unityadmin command line. When deploying applications to use managed routing, a DBA changes where the application database is managed.
For best practice, start with managing the lowest level of a database hierarchy first, by selecting where to manage the databases containing staging and base tables. Then progress upwards to any dependent databases containing application views.
You can decide where to manage objects individually or at the database level. When deploying a new application to Unity, work at the database level.
unityadmin> help database manage; Command: DATABASE MANAGE {<database> [ON <tdpid> [, <tdpid>, ...]]} [REASON '<reason>'] Description: Changes the managed location of all objects in the specified database to the specified systems. unityadmin> DATABASE MANAGE dbtest on db1;