EXPLAIN EXTENDED

SQL Server supports a really useful feature called indexed views. This means it lets you materialize results of some queries and build indexes over them. It’s as if you haven’t actually run the query yet - but it’s already complete, stored conveniently on the disk for you, ordered and waiting for you to read its results. Not all queries are eligible but some quite often used by the database developers are.

In this series, I'll describe three scenarios which could really benefit from using indexed views.

Scenario One: Unique multiple columns

Assume you are building a database for multiplayer online tic-tac-toe tournaments. The first thing you’d want would be recording game results: who played with whom and who won. This can be easily achieved with a simple layout:

Now we have additional requirement: no person should be able to play in a tournament more than once. How do we do that?

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