1
vote
1answer
70 views

Why add indexes to these columns in the Database?

I am trying to get my head around this code. It's from the Rails Tutorial Book and is part of the process of making a twitter like application. class CreateRelationships < ...
7
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4answers
268 views

how to explain indexes

This question is about teaching: When I learned databases, we talked about indexes being like the card catalog in the town library. We had at least an author index, a title index, then the Dewey ...