What is Materialised views in Teradata?
JOIN INDEX is a materialized view. Its definition is permanently stored and the data is updated whenever the base tables referred in the join index is updated. JOIN INDEX may contain one or more tables and also contain pre-aggregated data.
How do you create a materialized view?
CREATE MATERIALIZED VIEW defines a materialized view of a query. The query is executed and used to populate the view at the time the command is issued (unless WITH NO DATA is used) and may be refreshed later using REFRESH MATERIALIZED VIEW .
How do I change the view in Teradata?
A current view can be modified using the REPLACE VIEW statement. REPLACE VIEW redefines an existing view or, if the specified view does not exist, it creates a new view with the specified name. Following is the syntax to modify a view. The following example modifies the view Employee_View for adding additional columns.
Can you write to a materialized view?
Materialized views are disc-stored views that can be refreshed. Like views, they are defined by a database query. You can then write other queries against my_view just as you would with a traditional view or database table. You can’t insert data into a materialized view as you can with a table.
What is materialized view in database?
In computing, a materialized view is a database object that contains the results of a query. Whenever a query or an update addresses an ordinary view’s virtual table, the DBMS converts these into queries or updates against the underlying base tables.
Does Teradata support materialized view?
Abstract: Materialized views are implemented as join indexes in Teradata. Teradata supports a variety of join indexes including aggregate join indexes, single-table and multi-table join in- dexes, and sparse join indexes.
What is view and materialized view?
Views are generally used when data is to be accessed infrequently and data in table get updated on frequent basis. On other hand Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.
How do you maintain materialized view we can use?
To maintain materialized views, we can use
- ✅ Triggers.
- Pointers.
- Cascading.
What does replace view do?
REPLACE VIEW statement creates a new view, or re-creates the existing view in Teradata.
What is difference between create and replace view?
The CREATE VIEW statement creates a new view, or replaces an existing one if the OR REPLACE clause is given. If the view does not exist, CREATE OR REPLACE VIEW is the same as CREATE VIEW. If the view does exist, CREATE OR REPLACE VIEW is the same as ALTER VIEW.
What privilege is required for materialized view?
To create a materialized view in another user’s schema: You must have the CREATE ANY MATERIALIZED VIEW system privilege. The owner of the materialized view must have the CREATE TABLE system privilege.
Where is materialized view used?
You can use materialized views to achieve one or more of the following goals: Ease Network Loads. Create a Mass Deployment Environment. Enable Data Subsetting.
