Index impact on INSERT and UPDATE in SQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main effect of having indexes on INSERT operations in a database?

Indexes slow down INSERT operations because the database must update the index data structures every time a new row is added.

beginner

How do indexes affect UPDATE operations in a database?

Indexes can slow down UPDATE operations, especially if the updated columns are part of the index, because the index entries must be updated as well.

intermediate

Why might a database slow down when many indexes exist on a table during data modification?

Because each INSERT or UPDATE requires updating all related indexes, more indexes mean more work and slower data modification.

beginner

True or False: Indexes only affect SELECT queries and have no impact on INSERT or UPDATE performance.

False. Indexes improve SELECT speed but slow down INSERT and UPDATE because they need to be maintained.

intermediate

What is a good practice to balance index use for fast queries and acceptable INSERT/UPDATE speed?

Create indexes only on columns frequently used in queries and avoid unnecessary indexes on columns that change often.

How do indexes affect the speed of INSERT operations?

A They speed up INSERT operations

B They slow down INSERT operations

C They have no effect on INSERT operations

D They prevent INSERT operations

Indexes slow down INSERT operations because the database must update the index data structures for each new row.

Which type of operation is most affected by indexes?

A INSERT and UPDATE

B DELETE only

C SELECT only

D No operations are affected

INSERT and UPDATE operations are affected because indexes must be updated when data changes.

If you update a column that is part of an index, what happens?

A The update fails

B The index is ignored

C The index is automatically updated

D The index is deleted

The database updates the index entries to reflect the new values.

What is a downside of having many indexes on a table?

A Indexes get ignored

B Faster INSERT and UPDATE

C No change in performance

D Slower INSERT and UPDATE

More indexes mean more work to update them during data changes, slowing down INSERT and UPDATE.

What should you consider when creating indexes to balance performance?

A Index only frequently queried columns

B Index only columns that never change

C Never use indexes

D Index every column

Indexing frequently queried columns improves SELECT speed without overly slowing INSERT and UPDATE.

Explain how indexes impact the performance of INSERT and UPDATE operations in a database.

Think about what happens behind the scenes when data changes.

Describe best practices for using indexes to balance query speed and data modification performance.

Consider when indexes help and when they cause slowdowns.