Traditionally, relational databases required all tables to have a fixed data schema, i.e. a set of attributes (such as a “user” table with attributes “firstName”, “lastName” and “email”). You could change the schema by adding and removing attributes, but the available attributes were always know at a given point in time. For many use cases, this was acceptable. However, some applications have the need to store semi-structured data: entries where the attributes are not known ahead of time. Since 2012, ...
