Key / Valye (HashMap)
Tabular (BigTable)
Document Oriented
no Joins
no Complex Transactions
no SQL
databasse -> database
table -> collection
row -> document
JSON style document (BSON on the mongoDB servers)
no predefined schema
table has schema
collection does not have schema
we do not need to pre-create the collection, first insertion will create the collection
_id : timestamp+machine id+process id+counter
db.posts.find
$gt : greater than
index ensureindex comments.author 1