MongoDB Administrator's Guide

How it works...

Most of the commands are pretty self-explanatory. In steps 1 and 2, we view and delete index respectively. You can also use db.<collection>.dropIndexes() to delete all indexes. In step 3, we recreate the index on the city field, but this time we provide an additional parameter to customize the name of the index. This can be confirmed by viewing the output of the getIndexes() command, as shown in step 3. Next, in step 4, we try to create another index on the city field (in ascending order). However, as we already have an index on this field, this would be redundant and hence MongoDB does not allow it. If you change the 1 to -1 that is, change the sort order to descending, then your operation would succeed and you'd end up with ...