Interview Q&A / SQL & DBMS
SQL & DBMS interview questions
Joins, keys, normalisation, indexes and transactions for placement and backend interviews.
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- Can you INSERT, UPDATE or DELETE through a view?
Only if the view is simple, based on one table without DISTINCT, GROUP BY, aggregates or joins that make the target row ambiguous. Otherwise the database cannot map the change to base rows. WITH CHECK OPTION blocks rows leaving the view.
IntermediateQuick answer1 min read - What is a view, and how is a materialized view different?
A view is a saved query that runs each time you select from it and stores no data. A materialized view stores the query result physically, so reads are fast but the data is stale until refreshed.
IntermediateQuick answer1 min read