Aggregation
Aggregations in MongoDB are operations consisting of several steps that process multiple documents and return computed results. Aggregations are built around the concept of pipelines, through which data flows are gradually processed. In a pipeline, the output from the current processing unit is fed as input to the next unit (similar to chaining commands in Linux or a data-wrangling script in Python). In a pipeline, at each stage, a set of documents is fed to the processing unit's input and the output is fed to the following unit. This process ultimately provides solutions to potentially complex problems by breaking them down into smaller and simpler stages.
In this chapter, you will dive deeper into some of the more interesting and useful features of the MongoDB aggregation framework.
This chapter will cover the following topics:
- The purpose of the MongoDB aggregation framework
- Principles of aggregation and aggregation stages
- Basic aggregation...
