MongoDB
sudo service mongodb start pgrep mongo -l 978 mongod mongo MongoDB shell version: 2.6.10 connecting to: test show dbs School 0.078GB admin (empty) local 0.078GB use School switched to db School show collections system.indexes > db.createCollection('teacher') { "ok" : 1 } > db.createCollection('student') { "ok" : 1 } > db.student.insert({_id:1, sname: 'zhangsan', sage: 20}) WriteResult({ "nInserted" : 1 }) > db.student.save({_id:1, sname: 'zhangsan', sage: 22}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })