MongoDB command summary

Types of	Order	illustrate
server level	db.serverStatus()	Server Status Information
db.serverStatus().connections	Server connection information
db.fsyncLock()	Force refresh and add write lock
db.fsyncUnlock()	unlock
db.currentOp()	View the current lock status
help	help command
Database related commands	use dbname	select database
show dbs	list all databases
db	show current database
db.dropDatabase()	delete the current database
db.stats()	View current library statistics
db.printCollectionStats()	View statistics for each collection
Security and Authentication	show users	list users
db.addUser("username", "password")	Create ordinary users, can read and write
db.addUser("username", "password", true)	Create read-only user
db.removeUser("username")	delete users
db.auth("username", "password")	User Authentication
Collection operations	show collections	List the collections of the current database
db.createCollection("c1")	Create collection c1
db.c1.drop()	delete set c1
db.c1.renameCollection("c2")	Rename set c1 to c2
db.c1.count()	Displays the number of documents (rows) of collection c1
db.createCollection("c3",{capped:true, size:10000})	Create a special collection capped: true, indicating that the document structure of the collection cannot be modified; size: specify the space size of the collection, and the insertion operation will be APPENDed to the pre-allocated space file in order. The header starts overwriting the original data. Document deletion is not allowed, and updates cannot exceed the size of the original document. This kind of collection is very efficient, and it is suitable for some occasions where data is temporarily saved.
index operation	db.c1.ensureIndex({name:1})	Create a sequential index on the name field in collection c1
db.c1.ensureIndex({name:-1})	Create an inverted index on the name field in collection c1
db.c1.ensureIndex({name:1},{unique:1})	Create a unique sequential index on the name field in collection c1
db.c1.ensureIndex({name:1},{background:1})	Create indexes in the background without blocking other operations
Inquire	db.c1.getIndexes()	View the index information of c1
db.c1.dropIndex("name_1")	drop the index named name_1
db.c1.dropIndexes()	Drop all indexes except the _id primary key index
db.c1.totalIndexSize()	Display the total size of all indexes of the c1 collection
Additions, deletions and modifications	db.c1.insert({_id:1,name:"tom"})	Insert a new document in collection c1
db.c1.update({_id:1},{name:"jack"})	Modify the name field of the document whose _id is 1
db.c1.remove({name:"jack"})	Delete all documents with name: "jack" in collection c1
db.c1.remove({name:"tom"},1)	Delete only the first document with name: "tom" in collection c1
db.c1.save({_id:1,name:"lucy"})	新增或修改文档内容(主键已存在则修改，主键未指定或不存在则新增)
查询	db.c1.find({_id:5})	select * from c1 where _id=5
db.c1.find({_id:{$lt:5}})	select * from c1 where _id<5
db.c1.find({_id:{$lte:5}})	select * from c1 where _id<=5
db.c1.find({_id:{$gt:5}})	select * from c1 where _id>5
db.c1.find({_id:{$gte:5}})	select * from c1 where _id>=5
db.c1.find({_id:{$gt:0,$lt:9}})	select * from c1 where _id>0 and id<9
db.c1.find({_id:{$in:[1,3,5]}})	select * from c1 where _id in (1,3,5)
db.c1.find({_id:{$nin:[1,3,5]}})	select * from c1 where _id not in (1,3,5)
db.c1.find({_id:{$gt:9},name:"tom"})	select * from c1 where _id>9 and name="tom"
db.c1.find({$or:[{_id:{$gt:3}},{name:"tom"}]})	select * from c1 where _id>3 or name="tom"
db.c1.find({_id:{$gt:7}},{name:1,tel:1})	select name,tel from c1 where _id>7
db.cl.find().sort({name:1})	select * from c1 order by name
db.cl.find().sort({name:1})	select * from c1 order by name desc
db.cl.find().limit(10)	select * from c1 limit 10
db.User.find({tel:{$exists:1}});	查询存在tel字段的文档
db.User.find({name:/a/});	select * from c1 where name like '%a%'
db.User.find({name:/^a/});	select * from c1 where name like 'a%'