I created some more Delphi 10 Seattle samples to show off MongoDB and FireDAC functionality: LocalSQL, Indexing & Geospatial.
The first one queries some data from MongoDB allowing you to specify the match, sort and projection, then it stores the results in a DataSet. At that point you can use LocalSQL to write a SQL query against the result set. While FireDAC gives you full native support for MongoDB, it also puts the SQL back into NoSQL.
Indexing is used to improve your query performance. It is really easy to work with MongoDB queries with FireDAC.
And one of the cool features of MongoDB is that you can do spatial queries. Here is an example that shows how to create a Spatial index and then do a spatial query with FireDAC. This uses the restaurant data that is included with the shipping samples, so make sure you load the restaurant data first.
If you missed my previous post I had a MongoDB FireDAC and C++Builder sample.