What are snapshots? What are materialized views & where do we use them? What is a materialized view log?
ETL (extract, transform, and load) Testing Interview Questions
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5. What are snapshots? What are materialized views & where do we use them? What is a materialized view log?
- Snapshots are copies of read-only data of a master table.
- They are located on a remote node that is refreshed periodically to reflect the changes made to the master table.
- They are replica of tables
- Views are built by using attributes of one or more tables.
- View with single table can be updated, whereas view with multiple tables cannot be updated
Materialized View log
- A materialized view is a pre computed table that has aggregated or joined data from fact tables and dimension tables.
- To put it simple, a materialized view is an aggregate table.
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