What are the clusters? What are their
advantages?
Oracle clusters - Dec 03, 2008 at 15:00 PM by Rajmeet Ghai
What are the clusters? What are their advantages?
A cluster contains data from one or more tables. All these tables have one or
more columns in common. All the rows from all the tables that share the same
cluster key.
Example: cluster named workers with the cluster key column department, a cluster
size of 512 bytes, and storage parameter values
CREATE CLUSTER workers
(department NUMBER(4))
SIZE 512
STORAGE (initial 100K next 50K);
Advantages:
-
Clusters can speed up join queries.
-
Storage is saved since storing the field or fields comprising the Cluster Key
are stored once instead of multiple times.
-
Clustering does not does not affect the relational model (table schemas).
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