Sunday, January 16, 2011

How do you create materialized view in Teradata?

How do you create materialized view in Teradata?
Answer:

There is no such thing as a "materialized view" in Teradata. The equivalent in Teradata would be a join index (or aggregate index) with a corresponding view put on top of it. The command to create one is "CREATE JOIN INDEX...(lots of options)".

Join indices are maintained when the data is maintained. They cannot be accessed directly, but are invoked when the optimizer determines it is beneficial. Even though you cannot invoke a join index directly, you create a view that looks like the join index and in that way, it would be similar to having direct access. However, this approach does not guarantee that the join index will be used.

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