[MongoDB] CRUD와 Upsert

insertOne, insertMany


db.users.insertOne({name : "Alice", age : 25})
db.users.insertMany(
    {name : "Alice", age : 25},
    {name : "test", position : "dev"}    
)


------------

find, findOne


db.users.find()

db.users.find({age : {$gte : 25}})

db.users.findOne({name : "Alice"})


--------------

updateOne, updateMany

db.users.updateOne({name : "Alince"}, {$set : {age : 30}})

db.users.updateMany({city: "Busan"}, {$set : {city : "Daegu"}})


-------

delteOne, deleteMany

db.users.deleteOne({name : "Bob"})

db.users.deleteMany({city : "Incheon"})



-------
db.users.updateOne(
  { userId: 123 },           // userId가 123인 문서 찾기
  { $set: { name: "Alice" } }, // name 필드를 "Alice"로 변경
  { upsert: true }            // 문서 없으면 새로 만듦
)