MongoDB基本操作

db.stats();
db.getCollectionNames();
db.help()

db.users.find({})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.users.insert([{username:"wangyue"}])

db.users.find()
   .projection({})
   .sort({_id:-1})
   .limit(100)
   .count()
   
db.users.find({username:"馬悅"})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.users.insert([{username:"sunwukong"}])

db.users.find({})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.users.update({username:"sunwukong"}, 
    {$set:{address:"huaguoshan"}}, 
    { multi: false, upsert: false}
)

db.users.update({username:"馬悅"}, 
    {$set:{username:"tangseng"}}, 
    { multi: false, upsert: true}
)

db.users.update({username:"sunwukong"}, 
    {$unset:{address:0}}, 
    { multi: false, upsert: false}
)


db.users.update({username:"sunwukong"}, 
    {$set:{hobby:{cities:["beijing","shanghai","shengzhen"],movies:["sanguo","hero"]}}}, 
    { multi: false, upsert: false}
)

db.users.update({username:"tangseng"}, 
    {$set:{hobby:{movies:["A Chinese Odyssey","King of comedy"]}}}, 
    { multi: false, upsert: false}
)

db.users.find({"hobby.movies":"hero"})
   .projection({})
   .sort({_id:-1})
   .limit(100)

db.users.update({username:"tangseng"}, 
    {$push: {"hobby.movies":"Interstellar"}}, 
    { multi: false, upsert: false}
)
db.users.find({})
   .projection({})
   .sort({_id:-1})
   .limit(100)

db.users.remove({"hobby.cities":"beijing"}, {justOne: false})

db.users.remove({}, {justOne: false})
db.users.drop()

db.stats();

rs.slaveOk();
show dbs;


for(var i=1 ;i <=20000 ; i++){
    db.numbers.insert({num:i});
}

db.numbers.remove({}, {justOne: false})

db.numbers.find({})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   .count()
   
db.numbers.find({})
   .projection({})
   .sort({_id:1})

var  arr = [];

for(var i=1 ; i<=20000;i++){
    arr.push({num:i});
}
db.numbers.insert(arr)

db.numbers.find({num:500})
   .projection({})
   .sort({_id:-1})
   .limit(100)

db.numbers.find({num:{$gte: 19999}})
   .projection({})
   .sort({_id:-1})
   .limit(100)

db.numbers.find({num:{$lt: 30}})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.numbers.find({num:{$gt: 40,$lt:50}})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.numbers.find({num:{$gt: 19996}})
   .projection({})
   .sort({_id:-1})
   .limit(100)
   
db.numbers.find({})
   .projection({})
   .sort({_id:1})
   .limit(10)
   
db.numbers.find({})
   .projection({})
   .sort({_id:1})
   .skip(10)
   .limit(10)
   
db.numbers.find({})
   .projection({})
   .sort({_id:1})
   .skip(20)
   .limit(10)