Basic principles of database indexes

Are you using relational databases but the indexes are closed book for you? You absolutely don't know what the indexes are and how they work, or you are confused by various types of indexes (B-Tree, Hash, Bitmap) and you're not sure about their advantages or disadvantages? Or you just can't find out why a particular index is not used when evaluating a query? Maybe this article will help you to answer these questions ...

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