Time for action – creating indexes using the ResultReduce class

We will create a new index which will aggregate the World database to make a count of Cities that have the same name in different countries and return the CountryId key for each city as a single document. The following screenshot illustrates the expected result:

1. Start Visual Studio and open the RavenDB_CH05 solution.

2. Add a new class to the project, name it Cities_SameName and add the following code snippet:

   

   Tip

   We named the embedded class ReduceResult by convention. You can choose any other name for this class and place it outside the index class.

   We could use a String type in the ReduceResult class to store the document ID CountriesId (which is a string type), but we choose to create a second embedded class, for learning purposes and show that it is possible to create more complex structure.

3. Add a default constructor to the Cities_SameName class and within this constructor add the index Map function using the following code snippet...