What is a materialized view refresh group?
A refresh group refreshes all materialized views in the group together. By creating a refresh group and including both the employee and salary materialized views, the data integrity between the materialized views is maintained. Refresh groups are created and maintained using the dbms_refresh package.
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What is a materialized view refresh group?
A refresh group refreshes all materialized views in the group together. By creating a refresh group and including both the employee and salary materialized views, the data integrity between the materialized views is maintained. Refresh groups are created and maintained using the dbms_refresh package.
How do I schedule a materialized view to refresh?
To schedule a refresh for the materialized view, next to Repeats, select the Time Interval: Daily, Weekly, or Monthly. From the Select days menu, select Every weekday, or Every day. Specify the hour of the day.
How does a materialized view refresh work?
By default, a Complete Refresh is running within one transaction. At the beginning of a Complete Refresh, the old data of the materialized view is deleted, Then, the new data is inserted by running the underlying SQL query. During this time, users can still use the materialized view and see the old data.
How do you check if materialized view is refreshed or not?
select * from dba_refresh;select * from dba_refresh_children; select * from sys. v_$mvrefresh; Then below query to find the status of job.
Why materialized view is used?
Materialized views are basically used to increase query performance since it contains results of a query. They should be used for reporting instead of a table for a faster execution.
How do you populate a materialized view?
How it works.
- First, specify the view_name after the CREATE MATERIALIZED VIEW clause.
- Second, add the query that gets data from the underlying tables after the AS keyword.
- Third, if you want to load data into the materialized view at the creation time, use the WITH DATA option; otherwise, you use WITH NO DATA .
Can we create view on top of materialized view?
You can create more than one materialized view for the same base table.
Does view refresh automatically?
Yes, they are updated, every time you use them.
What are materialized views in SQL?
A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views. Collectively these objects are called master tables (a replication term) or detail tables (a data warehousing term).
What happens when I refresh a materialized view?
When you refresh the Materialized Views in a refresh group, all of the Materialized Views in that group will be refreshed to the same consistent point and time. If they are not refreshed, the data in an Materialized View will become “stale” and will not reflect the data as it looks in the target table.
What happens when a refresh group is placed in a view?
Warning! – When a materialized view is placed in a refresh group, it will be refreshed at the interval set in the group, not in the materialized view. For example, if a materialized view is created with a refresh interval of 3 mins and is then placed in a refresh group with an internal of 5 mins,…
What are the limitations of a refresh group?
There are a few practical limitations on refresh groups. The number of materialized views that can be in one refresh group is limited by the time required to execute the refresh. If a refresh group is created with 100 replicated materialized views, the time it takes to refresh the 100 views will probably be prohibitive.
What is a refresh group in Salesforce?
A refresh group refreshes all materialized views in the group together. By creating a refresh group and including both the employee and salary materialized views, the data integrity between the materialized views is maintained. Refresh groups are created and maintained using the dbms_refresh package.
