SQL Indexing

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These are notes that I took about SQL Indexing from http://use-the-index-luke.com

Introduction

  • An index makes a SQL query fast.
  • An index is a distinct structure in the DB that requires its own space.
  • A DB index is similar to index of a book - key concept is all entries are arranged in a well-defined order. Finding data in an ordered set is fast and easy because the sort order determines each entries position.