MongoDB - Mapping from SQL

There is one important thing I want to take note about the MongoDB in comparison with SQL:

SQL Terms/Concepts	MongoDB Terms/Concepts
database	database
table	collection
row	document or BSON document
column	field
index	index
table joins	embedded documents and linking
primary key Specify any unique column or column combination as primary key.	primary key In MongoDB, the primary key is automatically set to the _id field.
aggregation (e.g. group by)	aggregation pipeline See the SQL to Aggregation Mapping Chart.

Remember it if you are a mongodb newbie like me!!!!!!!


Source: http://docs.mongodb.org/manual/reference/sql-comparison/

(source: http://geekandpoke.typepad.com/geekandpoke/2011/01/nosql.html)