As it turns out, PostgreSQL has a number of ways of storing loosely structured data/documents in a column on a table. hstore is a data type available as a contrib package that allows you to store key/value structures just like a dictionary or hash. You can store data in JSON format on a text field, and then use PLV8 to JSON.parse() it right in the database. There is a native xml data type , along with a few interesting query functions that allow you to extract and operate on data that sits deep in an XML structure.
via NoSQL databases