var userSchema = new mongoose.Schema({
   name: String,
   email: String,
   createdOn: Date
 });

//ObjectId就類似于唯一鍵值
projectSchema.add({
  owner: mongoose.Schema.Types.ObjectId
});
//混合類型，顧名思義，就是說(shuō)里面可以放置任意類型的數(shù)據(jù)，有兩種方式創(chuàng)建該類型數(shù)據(jù)
//方式一：直接賦予一個(gè)空的字面量對(duì)象
vardjSchema= new mongoose.Schema({
  mixedUp: {}
});
//方式二：根據(jù)Schemas.Types中值來(lái)賦予
vardjSchema= new mongoose.Schema({
  mixedUp: Schema.Types.Mixed
});
//Array類型數(shù)據(jù)有兩種創(chuàng)建方式，一種是簡(jiǎn)單數(shù)組創(chuàng)建：
var userSchema = new mongoose.Schema({
  name: String,
  emailAddresses: [String]
});
//第二種方式就是復(fù)雜類型數(shù)據(jù)數(shù)組，例如我們可以再數(shù)組中添加不同類型的schemas:
var emailSchema = new mongoose.Schema({
  email: String,
  verified: Boolean
});
var userSchema = new mongoose.Schema({
  name: String,
  emailAddresses: [emailSchema]
});
//注意：如果定義一個(gè)空的數(shù)據(jù)的話，則會(huì)創(chuàng)建為一個(gè)混合類型數(shù)據(jù)的數(shù)組：
var emailSchema = new mongoose.Schema({
  email: String,
  verified: Boolean
});
var userSchema = new mongoose.Schema({
  name: String,
  emailAddresses: [emailSchema]
});

 projectSchema.statics.findByUserID = function (userid, callback) {
  this.find({ createdBy: userid }, '_id projectName', {sort: 'modifiedOn'}, callback);
 };

Model.findByUserID(userid,callback);

//路由規(guī)則：app.get('/project/byuser/:userid', project.byUser);
exports.byUser = function (req, res) {
  console.log("Getting user projects");
  if (req.params.userid){
    Project.findByUserID(req.params.userid,function (err, projects) {
      if(!err){
        console.log(projects);
        res.json(projects);
      }else{
        console.log(err);
        res.json({"status":"error", "error":"Error finding projects"});
      }
    });
  }else{
    console.log("No user id supplied");
    res.json({"status":"error", "error":"No user id supplied"});
  }
};

Mongoose.Model('User', userSchema);

//方式一：
var dbURI = 'mongodb://localhost/mydatabase';
mongoose.connect(dbURI);
//方式二：
var dbURI = 'mongodb://localhost/myadmindatabase';
var adminConnection = mongoose.createConnection(dbURI);
//如果需要聲明端口號(hào)：
var dbURI = 'mongodb://localhost:27018/mydatabase';
//如果需要定義用戶名和密碼：
var dbURI = 'mongodb://username:password@localhost/mydatabase';
//也可以像下面這樣傳一個(gè)對(duì)象類型的參數(shù)：
var dbURI = 'mongodb://localhost/mydatabase';
var dbOptions = {'user':'db_username','pass':'db_password'};
mongoose.connect(dbURI, dbOptions);

adminConnection.model( 'User', userSchema );

//方式一，在創(chuàng)建schema的時(shí)候定義collection的名字：
var userSchema = new mongoose.Schema({
  name: String,
  email: {type: String, unique:true}
},
{
  collection: 'myuserlist'
});
//方式二，在創(chuàng)建Model的時(shí)候定義collection的名字：
mongoose.model( 'User', userSchema, 'myuserlist' );

var user = new User({ name: 'Simon' });

 user.save(function (err) {
   if (err) return handleError(err);
 });

User.findOne({'name' : 'Sally', function(err,user) {
  if(!err){
    console.log(user);
  }
});
User.find({}, function(err, users) {
  if(!err){
    console.log(users);
  }
});

var newUser = new User({
  name: 'Simon Holmes',
  email: 'simon@theholmesoffice.com',
  lastLogin : Date.now()
}).save( function( err ){
  if(!err){
    console.log('User saved!');
  }
});

User.create({
  name: 'Simon Holmes',
  email: 'simon@theholmesoffice.com',
  lastLogin : Date.now()
}, function( err, user ){
  if(!err){
    console.log('User saved!');
    console.log('Saved user name: ' + user.name);
    console.log('_id of saved user: ' + user._id);
  }
});

var myQuery = User.find({'name' : 'Simon Holmes'});
myQuery.where('age').gt(18);
myQuery.sort('-lastLogin');
myQuery.select('_id name email');
myQuery.exec(function (err, users){
  if (!err){
    console.log(users); // output array of users found
  }
});

User.find({'name' : 'Simon Holmes'})
.where('age').gt(18)
.sort('-lastLogin')
.select('_id name email')
.exec(function (err, users){
  if (!err){
    console.log(users); // output array of users found
  }
});

Model.find(conditions, [fields], [options], [callback])

 User.find({'name', 'simon holmes'}, function(err, user) {});

 User.find({'name', 'simon holmes'}, 'name email',function(err, user) {
   //console.log('some thing');
 });

User.find({'name' : 'Simon Holmes'},
  null, // 如果使用null，則會(huì)返回所有的字段值
  {sort : {lastLogin : -1}}, // 降序排序
  function (err, users){
    if (!err){console.log(users);}
  });

 Model.find(query);
 Model.findOne(query);//返回查找到的所有實(shí)例的第一個(gè)
 Model.findById(ObjectID);//根據(jù)ObjectId查找到唯一實(shí)例

 User.findOne({'email' : req.body.Email},
 '_id name email',
 function(err, user) {
   //todo
 });

//在update方法中，options的可選設(shè)置為：
{
safe:true|false, //聲明是否返回錯(cuò)誤信息，默認(rèn)true
upsert:false|true, //聲明如果查詢不到需要更新的數(shù)據(jù)項(xiàng)，是否需要新插入一條記錄，默認(rèn)false
multi:false|true, //聲明是否可以同時(shí)更新多條記錄，默認(rèn)false
strict:true|false //聲明更新的數(shù)據(jù)中是否可以包含在schema定義之外的字段數(shù)據(jù)，默認(rèn)true
}
//對(duì)于findOneAndUpdate、findByIdAndUpdate這兩個(gè)方法，他們的options可選設(shè)置項(xiàng)為：
{
new:true|false, //聲明返回的數(shù)據(jù)時(shí)更新后的該是更新前的，如果為true則返回更新后的，默認(rèn)true
upsert:false|trure, 
sort:javascriptObject, //如果查詢返回多個(gè)文檔記錄，則可以進(jìn)行排序，在這里是根據(jù)傳入的javascript object對(duì)象進(jìn)行排序
select:String //這里聲明要返回的字段，值是一個(gè)字符串
}

 User.update({_id:user._id},{$set: {lastLogin: Date.now()}},function(){});

remove();
findOneAndRemove();
findByIdAndRemove();

User.remove({ name : /Simon/ } , function (err){
  if (!err){
    // 刪除名字中包含simon的所有用戶
  }
});

User.findOne({ email : 'simon@theholmesoffice.com'},function (err,user){
  if (!err){
    user.remove( function(err){
      // 刪除匹配到該郵箱的第一個(gè)用戶
    });
  }
});

User.findOneAndRemove({name : /Simon/},{sort : 'lastLogin', select : 'name email'},function (err, user){
  if (!err) {
    console.log(user.name + " removed");
    // Simon Holmes removed
  };
});

User.findByIdAndRemove(req.body._id,function (err, user) {
  if(err){
    console.log(err);
    return;
  }
  console.log("User deleted:", user);
});

email: { type: String, unique: true, required: true }

 var teenSchema = new Schema({
   age : {type: Number, min: 13, max:19}
 });

var weekdaySchema = new Schema({
  day : {type: String, match: /^(mon|tues|wednes|thurs|fri)day$/i}
});

var weekdays = ['monday', 'tuesday', 'wednesday', 'thursday','friday'];
var weekdaySchema = new Schema({
  day : {type: String, enum: weekdays}
});

{ 
  message: 'Validation failed',
  name: 'ValidationError',
  errors:{ 
    email:{
      message: 'Validator "required" failed for path email',
      name: 'ValidatorError',
      path: 'email',
      type: 'required' 
    },
    name:{ 
      message: 'Validator "required" failed for path name',
      name: 'ValidatorError',
      path: 'name',
      type: 'required' 
    } 
  } 
}

if(err){
  Object.keys(err.errors).forEach(function(key) {
    var message = err.errors[key].message;
    console.log('Validation error for "%s": %s', key, message);
  });
}

var lengthValidator = function(val) {
  if (val && val.length >= 5){
    return true;
  }
  return false;
};
//usage:
name: {type: String, required: true, validate: lengthValidator }

//code 1
validate: { validator: lengthValidator, msg: 'Too short' }

//code 2
var weekdaySchema = new Schema({
  day : {type: String, validate: {validator:/^(mon|tues|wednes|thurs|fri)day$/i, msg: 'Not a day' }
});

 var validateLength = [lengthValidator, 'Too short' ];
 var validateDay = [/^(mon|tues|wednes|thurs|fri)day$/i, 'Not a day' ];
 //usage:
 name: {type: String, required: true, validate: validateLength }
 day : {type: String, validate: validateDay }

 var validateLength = [
   {validator: lengthValidator, msg: 'Too short'}
 ];

 var validateUsername = [
   {validator: lengthValidator, msg: 'Too short'} ,
   {validator: /^[a-z]+$/i, msg: 'Letters only'}
 ];

userSchema.path('name').validate(lengthValidator, 'Too short');
userSchema.path('name').validate(/^[a-z]+$/i, 'Letters only');