Data Dictionary | Teradata Unity - 17.00 - Unity Data Dictionary - Continuous Availability - Teradata Unity

Teradata® Unity™ User Guide

Product
Continuous Availability
Teradata Unity
Release Number
17.00
Published
September 2020
Language
English (United States)
Last Update
2020-09-15
dita:mapPath
fmz1594836948704.ditamap
dita:ditavalPath
qqk1595871525984.ditaval

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.

Unity data dictionary is maintained automatically. As clients create new objects, the objects are added to the Unity data dictionary. As objects are dropped, they are removed from the data dictionary.

When working with a new object or database created directly on one or more Teradata systems, you can manually run a data dictionary scan. When a new system is added to the Unity environment, a complete scan of the system and its objects is run automatically, to inventory all the objects that exist on the system. When you add a system, you can skip the full system scan using the NOSCAN option with the SYSTEM ADD command from unityadmin.
If you do not see the database you want to scan on the Databases screen, perform a full system scan from the Systems screen.

After executing a data dictionary scan to find where an object exists, you can manage the object on all the systems on which the object exists or on a single system of the set, if the objects are not yet synchronized. Controlling where an object or database is managed can be done using Unity UI or the unityadmin command line. When deploying applications to use managed routing, you can change where the application database is managed.

For best practice, start with managing the lowest level of a database hierarchy by selecting where to manage the databases containing staging and base tables. Then progress upwards to any dependent databases containing application views.

You can choose where to manage objects individually or at the database level. When deploying a new application to Unity, work at the database level.

You can also change where a database is managed at the unityadmin prompt:
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;