DyBASE: object oriented embedded database
http://www.garret.ru/dybase.html


ZODB: a native object database for Python
http://www.zodb.org/index.html


MongoDB: document-oriented database management system
http://docs.mongodb.org/manual/

A Mongo system holds a set of databases
A database holds a set of collections
A collection holds a set of documents
A document is a set of fields
A field is a key-value pair
A key is a name (string)
A value is a
・basic type like string, integer, float, timestamp, binary, etc.,
・a document, or
・an array of values