use my_test;
db.user.insert({name:"jiangjie",nickname:"zongtong"})
db.user.find()
db.user.insert({name:"jiangjie",nickname:"zongtong"})
db.user.insert({name:"孙悟空",username:"sunwukong"})
db.user.find()
db.user.find().count()
db.user.find({username:"sunwukong"})
db.user.update({username:"sunwukong"},{$set:{address:"huaguoshan"}});
db.user.update({name:"sunzhong"},{$set:{username:"tangseng"},$unset:{name:"孙中山"}});
db.user.find()
db.user.update({username:"tangseng"},{username:"zhubajie"})
db.user.update({username:"sunwukong"},{$unset:{address:"huaguoshan"}})
db.user.update({username:"sunwukong"},{$set:{hobby:{cities:["beijing","shanghai","shenzhen"]}}})
db.user.update({username:"tangseng"},{$set:{hobby:{movies:["A Chinese Odyssey","King of comedy"]}}})
db.user.find()
db.user.find({"hobby.movies":"A Chinese Odyssey"});
db.user.update({username:"tangseng"},{$push:{"hobby.movies":"Interstellar"}})
db.user.deleteOne({"hobby.cities":"beijing"});
db.user.remove({});
db.user.find();
var arr = [];
for(var i=0;i<20000;i++){
arr[i]={num:i};
}
db.numbers.insert(arr);
db.numbers.find();
db.numbers.find({num:500});
db.numbers.find({num:{$gt:5000}});
db.numbers.find({num:{$lt:30}});
db.numbers.find({num:{$lt:50,$gt:40}});
db.numbers.find({num:{$gt:19996}});
db.numbers.find().limit(10);
db.numbers.find().skip(10).limit(10);
db.numbers.find().skip(20).limit(10);
db.emp.find({sal:{$lt:2000}});
db.emp.find({sal:{$lt:2000,$gt:1000}});
db.emp.find({$or:[{sal:{$lt:1000}},{sal:{$gt:2500}}]});
db.dept.find();
db.emp.find();
db.emp.find({depno:10});
db.emp.find({depno:30});
db.emp.find({mgr:7698})
db.emp.updateMany({sal:{$lte:1000}} , {$inc:{sal:400}});
db.emp.find();
db.emp.find({}).sort({sal:1,empno:-1});
db.emp.find({},{ename:1 , _id:0 , sal:1});