mongodb常用命令
db.foo.find()
show dbs;
db.dropDatabase();
db.userInfo.find({age: {$gt: 22}})
db.users.save({name: ‘zhangsan’, age: 25, sex: true});
db.users.update({age: 25}, {$set: {name: 'changeName'}}, false, true);
db.users.remove({age: 132});
......等等
