In Chapter 5, Multi-Document ACID Transactions, we worked through two use cases of the new transactions capability using code for Ruby and Python. In this chapter, we will dive deeper into the aggregation framework, learning how it can be useful. We will also look at the operators that are supported by MongoDB.

To learn this information, we will use aggregations to process transaction data from the Ethereum blockchain. The complete source code is available at https://github.com/PacktPublishing/Mastering-MongoDB-4.x-Second-Edition.

In this chapter, we will cover the following topics:

• Why aggregation?
• Different aggregation operators
• Limitations