Unity Data Dictionary - Teradata Unity

Teradata® Unity™ User Guide

Product
Teradata Unity
Release Number
16.51
Published
May 2020
Language
English (United States)
Last Update
2020-06-01
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oic1588030762460.ditamap
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dita:id
B035-2520
lifecycle
previous
Product Category
Analytical Ecosystem

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.

When working with a new object or database that was created directly on one or more Teradata systems, a DBA may 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.
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, 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.

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