MongoDB SQL 区别

下表展示了各种 SQL 术语和概念，与 MongoDB 术语和概念类似。

SQL 概念	MongoDB 概念
database	Database
table	Collection
row	document or BSON document
column	field
index	index
table joins	$lookup, embedded document
primary key	primary key
In SQL, we can specify any unique column or column combination as the primary key.	In MongoDB, we don't need to set the primary key. The _id field is automatically set to the primary key.
aggregation	aggregation pipeline
SELECT INTO NEW_TABLE	$out
MERGE INTO TABLE	$merge
transactions	transactions