Time for action – creating multimap indexes

We will create a new index class that aggregates the World database and makes a count of Cities in each country using a multi map index.

1. Start Visual Studio and open the RavenDB_CH05 solution.

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

   

3. Add a default constructor to the Cities_MMCitiesByCountry class and within this constructor add two Map functions using the following code snippet:

   

4. Within the Cities_MMCitiesByCountry class constructor add the index Reduce function using the following code snippet:

   

5. Modify the Main method in the Program class using the following code snippet.

   

6. Save all files, build and run the solution.

7. In Management Studio, execute the Cities/MMCitiesByCountry index.

What just happened?

You just created the multi map Cities_MMCitiesByCountry index class. This index aims to aggregate the World database and get the cities count in each country.

The Cities_MMCitiesByCountry class inherits...