Databases · Junior · Question 43 of 75

What is an index for?

1To back up a table
✓Correct answer: To find rows quickly without scanning the whole table, like an index at the back of a book
3To number rows in a table

Explanation

Indexes speed up WHERE, JOIN and ORDER BY, but take space and slow down writes, because every insert and update must also update the index.

Further reading

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