All storage systems use indexes to find data quickly when a query is processed. In a database system, an index is a data structure that improves data retrieval operations. Therefore, creating a proper index can drastically increase the performance of an application.
An index in a relational database is very similar to an index in the back of a book. When a database server has no index to use for searching, the result is similar to the reader who looks at every page in a book to find a word. The database engine needs to visit every row in the table. In relational database terminology, we call this behavior a table scan, which becomes slower and more expensive as a table grows to thousands or millions of rows.
RavenDB indexes are used to retrieve data from the server but they do not work the same way as relational database indexes work. The main difference is that relational database indexes are schema-based and RavenDB is a schema-less document-oriented database, which means...