cp mongod&mongo -> bin
vim conf :
    port = 12345
    dbpath = data
    logpath = log/mongod.log
    //linux下启动一个后台进程，win下无效
    fork = true

./bin/mongod -f conf/mongod.conf

./bin/mongo 127.0.0.1:12345/mydb

   Tank.findById(id, function (err, tank) {
     if (err) return handleError(err);

     tank.size = 'large';
     tank.save(function (err) {
       if (err) return handleError(err);
       res.send(tank);
     });
   });

Person.findOne({ 'name.last': 'Ghost' }, 'name occupation', function (err, person) {
 if (err) return handleError(err);
 console.log('%s %s is a %s.', person.name.first, person.name.last, person.occupation) // Space Ghost is a talk show host.
})

var breakfastSchema = new Schema({
     eggs: {
       type: Number,
       min: [6, 'Too few eggs'],
       max: 12
     },
     bacon: {
       type: Number,
       required: [true, 'Why no bacon?']
     },
     drink: {
       type: String,
       enum: ['Coffee', 'Tea']
     }
   });
   var Breakfast = db.model('Breakfast', breakfastSchema);

   var badBreakfast = new Breakfast({
     eggs: 2,
     bacon: 0,
     drink: 'Milk'
   });
   var error = badBreakfast.validateSync();
   assert.equal(error.errors['eggs'].message,
     'Too few eggs');
   assert.ok(!error.errors['bacon']);
   assert.equal(error.errors['drink'].message,
     '`Milk` is not a valid enum value for path `drink`.');

   badBreakfast.bacon = null;
   error = badBreakfast.validateSync();
   assert.equal(error.errors['bacon'].message, 'Why no bacon?');

 var userSchema = new Schema({
     phone: {
       type: String,
       validate: {
         validator: function(v) {
           return /\d{3}-\d{3}-\d{4}/.test(v);
         },
         message: '{VALUE} is not a valid phone number!'
       },
       required: [true, 'User phone number required']
     }
   });

var schema = new Schema(..);
 schema.pre('save', function(next) {
 // do stuff
 next();
});

var schema = new Schema(..);

// `true` means this is a parallel middleware. You **must** specify `true`
// as the second parameter if you want to use parallel middleware.
schema.pre('save', true, function(next, done) {
 // calling next kicks off the next middleware in parallel
 next();
 setTimeout(done, 100);
});

schema.pre('save', function(next) {
 // You **must** do `new Error()`. `next('something went wrong')` will
 // **not** work
 var err = new Error('something went wrong');
 next(err);
});

// later...

myDoc.save(function(err) {
 console.log(err.message) // something went wrong
});