Model.find(query, fields, options, callback)

Model.find({ ‘some.value‘: 5 }, function (err, docs) {
  // docs is an array
});

Model.findOne

Model.findOne({ age: 5}, function (err, doc){
  // doc is a Document
});

Model.findById

Model.findById(obj._id, function (err, doc){
  // doc is a Document
});

Model.count

Model.count(conditions, callback);

Model.remove

Model.remove(conditions, callback);

Model.distinct

Model.distinct(field, conditions, callback);

Model
.where(‘age‘).gte(25)
.where(‘tags‘).in([‘movie‘, ‘music‘, ‘art‘])
.select(‘name‘, ‘age‘, ‘tags‘)
.skip(20)
.limit(10)
.asc(‘age‘)
.slaveOk()
.hint({ age: 1, name: 1 })
.exec(callback);

Model.$where(‘this.firstname === this.lastname‘).exec(callback)

var query = Model.find({});

query.where(‘field‘, 5);
query.limit(5);
query.skip(100);

query.exec(function (err, docs) {
  // called when the `query.complete` or `query.error` are called
  // internally
});

Model.update

var conditions = { name: ‘borne‘ }// 条件
  , update = { $inc: { visits: 1 }}//修改
  , options = { multi: true };//选项 multi 修改多个 

Model.update(conditions, update, options, callback);

function callback (err, numAffected) {
  // numAffected is the number of updated documents
})

Model.findOne({ name: ‘borne‘ }, function (err, doc){//doc 是模型
  doc.name = ‘jason borne‘;
  doc.visits.$inc();
  doc.save();
});