Why should you index foreign key columns in large OLTP tables?

Problem Statement

Explanation

When a parent row changes or is deleted, the engine must find matching children. An index on the child foreign key avoids full scans and reduces lock time. It also makes child-to-parent joins fast in day-to-day queries.

Code Solution

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CREATE INDEX idx_orders_customer_id ON orders(customer_id);

Practice Sets

This question appears in the following practice sets:

Indexes & Query Performance Essentials

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Why should you index foreign key columns in large OLTP tables?

Problem Statement

Explanation

Code Solution

Practice Sets

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Why should you index foreign key columns in large OLTP tables?

Problem Statement

Explanation

Code Solution

Practice Sets

Related Questions

Which SQL statement retrieves all columns and rows from a table named employees?

Which clause filters rows before aggregation and affects which rows are grouped?

What is the default sort order when ORDER BY is used without ASC or DESC?

Which construct is commonly used to paginate results in SQL engines like Postgres and MySQL?

Which predicate correctly checks for missing values in standard SQL?

More from SQL & Databases

Master Interviews
Anywhere, Anytime