In this chapter, we explained what relations are, why they’re useful, and
how to work with them using SQL code.
SQL databases are useful for many real-world settings. For example, SQL databases typically have robust data recovery mechanisms—if the computer crashes while in the middle of a SQL operation, the database system can recover as much data as possible without corruption. As mentioned earlier, SQL databases can also handle larger scale; organizations use SQL databases to store and query databases that are far too large to analyze in-memory using
pandas code. These are just a few reasons why SQL is an important part of the data science toolbox, and we expect that many readers will soon encounter SQL code as part of their work.