Indexing data structures is a general technique to improve the speed of data lookups.
The purpose of storing an index is to optimize speed and performance in finding relevant documents for a search query. Without an index, the search process would scan every document in the corpus, which would require considerable time and computing power.
Indexes may benefit both read queries and updates. Many people wrongly believe indexes are only good for read queries. In general, there are three methods of indexing - non-clustered, clustered and cluster.
References:
Top Indexing Questions
- How does database indexing work?
- How do MySQL indexes work?
- What do Clustered and Non-Clustered index actually mean?
- Differences between INDEX, PRIMARY, UNIQUE, FULLTEXT in MySQL?
- Multiple Indexes vs Multi-Column Indexes
- How to see indexes for a database or table in MySQL?
- What is an index in SQL?
- MySQL indexes - what are the best practices?
- When should I use a composite index?
- How important is the order of columns in indexes?
By these questions, you will clear your concepts regarding indexing. And you can ask similar questions (not duplicate) with this tag.