SQL is great for relational tables with a two-dimensional structure of rows and fixed columns. It's not so great for schemaless object databases or navigating

SQL is great for relational tables with a two-dimensional structure of rows and fixed columns. It's not so great for schemaless object databases or navigating nested arrays and hashmaps. Some relational databases can store JSON objects, and incorporate SQL extensions to navigate those objects. But in general, SQL doesn't seem to be a great tool for data that isn't a collection of two-dimensional data structures.