模型

Model()

参数

• doc «Object» values with which to create the document

Model constructor

Provides the interface to MongoDB collections as well as creates document instances.

Model.prototype.db

Connection the model uses.

Model.prototype.collection

Collection the model uses.

Model.prototype.modelName

Model.prototype.$where

Additional properties to attach to the query when calling save() and isNew is false.

Model.prototype.baseModelName

If this is a discriminator model, baseModelName is the name of the base model.

Model.prototype.save()

参数

• [fn] «Function» optional callback

返回

Saves this document.

示例

product.sold = Date.now();
product.save(function (err, product) {
  if (err) ..
})

The callback will receive three parameters

1. err if an error occurred
2. product which is the saved product

As an extra measure of flow control, save will return a Promise.

示例

product.save().then(function(product) {
   ...
});

Model.prototype.increment()

Signal that we desire an increment of this documents version.

示例

Model.findById(id, function (err, doc) {
  doc.increment();
  doc.save(function (err) { .. })
})

Model.prototype.remove()

参数

• [fn] «function(err,product)» optional callback

返回

Removes this document from the db.

示例

product.remove(function (err, product) {
  if (err) return handleError(err);
  Product.findById(product._id, function (err, product) {
    console.log(product)
  })
})

As an extra measure of flow control, remove will return a Promise (bound to fn if passed) so it could be chained, or hooked to recive errors

示例

product.remove().then(function (product) {
   ...
}).catch(function (err) {
   assert.ok(err)
})

Model.prototype.model()

参数

• name «String» model name

Returns another Model instance.

示例

var doc = new Tank;
doc.model('User').findById(id, callback);

Model.discriminator()

参数

• schema «Schema» discriminator model schema

Adds a discriminator type.

示例

function BaseSchema() {
  Schema.apply(this, arguments);

  this.add({
    name: String,
    createdAt: Date
  });
}
util.inherits(BaseSchema, Schema);

var PersonSchema = new BaseSchema();
var BossSchema = new BaseSchema({ department: String });

var Person = mongoose.model('Person', PersonSchema);
var Boss = Person.discriminator('Boss', BossSchema);

Model.init()

参数

Performs any async initialization of this model against MongoDB. Currently, this function is only responsible for building [indexes, unless [autoIndex is turned off.

This function is called automatically, so you don't need to call it. This function is also idempotent, so you may call it to get back a promise that will resolve when your indexes are finished building as an alternative to MyModel.on('index')

示例

var eventSchema = new Schema({ thing: { type: 'string', unique: true }})


var Event = mongoose.model('Event', eventSchema);

Event.init().then(function(Event) {


  console.log('Indexes are done building!');
});

Model.ensureIndexes()

参数

• [cb] «Function» optional callback

返回

Sends createIndex commands to mongo for each index declared in the schema. The createIndex commands are sent in series.

示例

Event.ensureIndexes(function (err) {
  if (err) return handleError(err);
});

After completion, an index event is emitted on this Model passing an error if one occurred.

示例

var eventSchema = new Schema({ thing: { type: 'string', unique: true }})
var Event = mongoose.model('Event', eventSchema);

Event.on('index', function (err) {
  if (err) console.error(err);
})

NOTE: It is not recommended that you run this in production. Index creation may impact database performance depending on your load. Use with caution.

Model.createIndexes()

参数

• [cb] «Function» optional callback

返回

Similar to ensureIndexes(), except for it uses the [createIndex function. The ensureIndex() function checks to see if an index with that name already exists, and, if not, does not attempt to create the index. createIndex() bypasses this check.

Model.prototype.schema

Model.prototype.base

Base Mongoose instance the model uses.

Model.prototype.discriminators

Registered discriminators for this model.

Model.translateAliases()

参数

• raw «Object» fields/conditions that may contain aliased keys

返回

• «Object» the translated 'pure' fields/conditions

Translate any aliases fields/conditions so the final query or document object is pure

示例

Character
  .find(Character.translateAliases({
    '名': 'Eddard Stark'
  })
  .exec(function(err, characters) {})

注释

Only translate arguments of object type anything else is returned raw

Model.remove()

参数

返回

Removes all documents that match conditions from the collection. To remove just the first document that matches conditions, set the single option to true.

示例

Character.remove({ name: 'Eddard Stark' }, function (err) {});

注释

This method sends a remove command directly to MongoDB, no Mongoose documents are involved. Because no Mongoose documents are involved, no middleware (hooks) are executed.

Model.deleteOne()

参数

返回

Deletes the first document that matches conditions from the collection. Behaves like remove(), but deletes at most one document regardless of the single option.

示例

Character.deleteOne({ name: 'Eddard Stark' }, function (err) {});

注释

Like Model.remove(), this function does not trigger pre('remove') or post('remove') hooks.

---

Model.deleteMany()

参数

返回

Deletes all of the documents that match conditions from the collection. Behaves like remove(), but deletes all documents that match conditions regardless of the single option.

示例

Character.deleteMany({ name: /Stark/, age: { $gte: 18 } }, function (err) {});

注释

Like Model.remove(), this function does not trigger pre('remove') or post('remove') hooks.

---

Model.find()

参数

返回

Finds documents

The conditions are cast to their respective SchemaTypes before the command is sent.

示例

MyModel.find({ name: 'john', age: { $gte: 18 }});


MyModel.find({ name: 'john', age: { $gte: 18 }}, function (err, docs) {});


MyModel.find({ name: /john/i }, 'name friends', function (err, docs) { })


MyModel.find({ name: /john/i }, null, { skip: 10 })


MyModel.find({ name: /john/i }, null, { skip: 10 }, function (err, docs) {});


var query = MyModel.find({ name: /john/i }, null, { skip: 10 })
query.exec(function (err, docs) {});


var query = MyModel.find({ name: /john/i }, null, { skip: 10 });
var promise = query.exec();
promise.addBack(function (err, docs) {});

Model.findById()

参数

返回

Finds a single document by its _id field. findById(id) is almost* equivalent to findOne({ _id: id }). If you want to query by a document's _id, use findById() instead of findOne().

The id is cast based on the Schema before sending the command.

This function triggers the following middleware.

• Except for how it treats undefined. If you use findOne(), you'll see that findOne(undefined) and findOne({ _id: undefined }) are equivalent to findOne({}) and return arbitrary documents. However, mongoose translates findById(undefined) into findOne({ _id: null }).

示例

Adventure.findById(id, function (err, adventure) {});


Adventure.findById(id).exec(callback);


Adventure.findById(id, 'name length', function (err, adventure) {});


Adventure.findById(id, 'name length').exec(callback);


Adventure.findById(id, '-length').exec(function (err, adventure) {});


Adventure.findById(id, 'name', { lean: true }, function (err, doc) {});


Adventure.findById(id, 'name').lean().exec(function (err, doc) {});

Model.findOne()

参数

返回

Finds one document.

The conditions are cast to their respective SchemaTypes before the command is sent.

Note: conditions is optional, and if conditions is null or undefined, mongoose will send an empty findOne command to MongoDB, which will return an arbitrary document. If you're querying by _id, use findById() instead.

示例

Adventure.findOne({ type: 'iphone' }, function (err, adventure) {});


Adventure.findOne({ type: 'iphone' }).exec(function (err, adventure) {});


Adventure.findOne({ type: 'iphone' }, 'name', function (err, adventure) {});


Adventure.findOne({ type: 'iphone' }, 'name').exec(function (err, adventure) {});


Adventure.findOne({ type: 'iphone' }, 'name', { lean: true }, callback);


Adventure.findOne({ type: 'iphone' }, 'name', { lean: true }).exec(callback);


Adventure.findOne({ type: 'iphone' }).select('name').lean().exec(callback);

Model.count()

参数

返回

Counts number of matching documents in a database collection.

示例

Adventure.count({ type: 'jungle' }, function (err, count) {
  if (err) ..
  console.log('there are %d jungle adventures', count);
});

Model.distinct()

参数

返回

Creates a Query for a distinct operation.

Passing a callback immediately executes the query.

示例

Link.distinct('url', { clicks: {$gt: 100}}, function (err, result) {
  if (err) return handleError(err);

  assert(Array.isArray(result));
  console.log('unique urls with more than 100 clicks', result);
})

var query = Link.distinct('url');
query.exec(callback);

Model.where()

参数

• [val] «Object» optional value

返回

Creates a Query, applies the passed conditions, and returns the Query.

For example, instead of writing:

User.find({age: {$gte: 21, $lte: 65}}, callback);

we can instead write:

User.where('age').gte(21).lte(65).exec(callback);

Since the Query class also supports where you can continue chaining

User
.where('age').gte(21).lte(65)
.where('name', /^b/i)
... etc

Model.prototype.$where()

参数

• argument «String,Function» is a javascript string or anonymous function

返回

Creates a Query and specifies a $where condition.

Sometimes you need to query for things in mongodb using a JavaScript expression. You can do so via find({ $where: javascript }), or you can use the mongoose shortcut method $where via a Query chain or from your mongoose Model.

Blog.$where('this.username.indexOf("val") !== -1').exec(function (err, docs) {});

Model.findOneAndUpdate()

参数

返回

Issues a mongodb findAndModify update command.

Finds a matching document, updates it according to the update arg, passing any options, and returns the found document (if any) to the callback. The query executes immediately if callback is passed else a Query object is returned.

选项

• new: bool - if true, return the modified document rather than the original. defaults to false (changed in 4.0)
• upsert: bool - creates the object if it doesn't exist. defaults to false.
• fields: {Object|String} - Field selection. Equivalent to .select(fields).findOneAndUpdate()
• maxTimeMS: puts a time limit on the query - requires mongodb >= 2.6.0
• sort: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
• runValidators: if true, runs [update validators on this command. Update validators validate the update operation against the model's schema.
• setDefaultsOnInsert: if this and upsert are true, mongoose will apply the [defaults specified in the model's schema if a new document is created. This option only works on MongoDB >= 2.4 because it relies on [MongoDB's $setOnInsert operator.
• rawResult: if true, returns the [raw result from the MongoDB driver
• strict: overwrites the schema's [strict mode option for this update

示例

A.findOneAndUpdate(conditions, update, options, callback)
A.findOneAndUpdate(conditions, update, options)
A.findOneAndUpdate(conditions, update, callback)
A.findOneAndUpdate(conditions, update)
A.findOneAndUpdate()

注释

All top level update keys which are not atomic operation names are treated as set operations:

示例

var query = { name: 'borne' };
Model.findOneAndUpdate(query, { name: 'jason bourne' }, options, callback)


Model.findOneAndUpdate(query, { $set: { name: 'jason bourne' }}, options, callback)

This helps prevent accidentally overwriting your document with { name: 'jason bourne' }.

注释

Values are cast to their appropriate types when using the findAndModify helpers. However, the below are not executed by default.

• defaults. Use the setDefaultsOnInsert option to override.

findAndModify helpers support limited validation. You can enable these by setting the runValidators options, respectively.

If you need full-fledged validation, use the traditional approach of first retrieving the document.

Model.findById(id, function (err, doc) {
  if (err) ..
  doc.name = 'jason bourne';
  doc.save(callback);
});

Model.findByIdAndUpdate()

参数

返回

Issues a mongodb findAndModify update command by a document's _id field. findByIdAndUpdate(id, ...) is equivalent to findOneAndUpdate({ _id: id }, ...).

Finds a matching document, updates it according to the update arg, passing any options, and returns the found document (if any) to the callback. The query executes immediately if callback is passed else a Query object is returned.

This function triggers the following middleware.

选项

• new: bool - true to return the modified document rather than the original. defaults to false
• upsert: bool - creates the object if it doesn't exist. defaults to false.
• runValidators: if true, runs [update validators on this command. Update validators validate the update operation against the model's schema.
• setDefaultsOnInsert: if this and upsert are true, mongoose will apply the [defaults specified in the model's schema if a new document is created. This option only works on MongoDB >= 2.4 because it relies on [MongoDB's $setOnInsert operator.
• sort: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
• select: sets the document fields to return
• rawResult: if true, returns the [raw result from the MongoDB driver
• strict: overwrites the schema's [strict mode option for this update

示例

A.findByIdAndUpdate(id, update, options, callback)
A.findByIdAndUpdate(id, update, options)
A.findByIdAndUpdate(id, update, callback)
A.findByIdAndUpdate(id, update)
A.findByIdAndUpdate()

注释

All top level update keys which are not atomic operation names are treated as set operations:

示例

Model.findByIdAndUpdate(id, { name: 'jason bourne' }, options, callback)


Model.findByIdAndUpdate(id, { $set: { name: 'jason bourne' }}, options, callback)

This helps prevent accidentally overwriting your document with { name: 'jason bourne' }.

注释

Values are cast to their appropriate types when using the findAndModify helpers. However, the below are not executed by default.

• defaults. Use the setDefaultsOnInsert option to override.

findAndModify helpers support limited validation. You can enable these by setting the runValidators options, respectively.

If you need full-fledged validation, use the traditional approach of first retrieving the document.

Model.findById(id, function (err, doc) {
  if (err) ..
  doc.name = 'jason bourne';
  doc.save(callback);
});

Model.findOneAndRemove()

参数

返回

Issue a mongodb findAndModify remove command.

Finds a matching document, removes it, passing the found document (if any) to the callback.

Executes immediately if callback is passed else a Query object is returned.

This function triggers the following middleware.

选项

• sort: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
• maxTimeMS: puts a time limit on the query - requires mongodb >= 2.6.0
• select: sets the document fields to return
• rawResult: if true, returns the [raw result from the MongoDB driver
• strict: overwrites the schema's [strict mode option for this update

示例

A.findOneAndRemove(conditions, options, callback)
A.findOneAndRemove(conditions, options)
A.findOneAndRemove(conditions, callback)
A.findOneAndRemove(conditions)
A.findOneAndRemove()

Values are cast to their appropriate types when using the findAndModify helpers. However, the below are not executed by default.

• defaults. Use the setDefaultsOnInsert option to override.

findAndModify helpers support limited validation. You can enable these by setting the runValidators options, respectively.

If you need full-fledged validation, use the traditional approach of first retrieving the document.

Model.findById(id, function (err, doc) {
  if (err) ..
  doc.name = 'jason bourne';
  doc.save(callback);
});

Model.findByIdAndRemove()

参数

返回

Issue a mongodb findAndModify remove command by a document's _id field. findByIdAndRemove(id, ...) is equivalent to findOneAndRemove({ _id: id }, ...).

Finds a matching document, removes it, passing the found document (if any) to the callback.

Executes immediately if callback is passed, else a Query object is returned.

This function triggers the following middleware.

选项

• sort: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
• select: sets the document fields to return
• rawResult: if true, returns the [raw result from the MongoDB driver
• strict: overwrites the schema's [strict mode option for this update

示例

A.findByIdAndRemove(id, options, callback)
A.findByIdAndRemove(id, options)
A.findByIdAndRemove(id, callback)
A.findByIdAndRemove(id)
A.findByIdAndRemove()

Model.create()

参数

• [callback] «Function» callback

返回

Shortcut for saving one or more documents to the database. MyModel.create(docs) does new MyModel(doc).save() for every doc in docs.

This function triggers the following middleware.

示例

Candy.create({ type: 'jelly bean' }, { type: 'snickers' }, function (err, jellybean, snickers) {
  if (err)
});


var array = [{ type: 'jelly bean' }, { type: 'snickers' }];
Candy.create(array, function (err, candies) {
  if (err)

  var jellybean = candies[0];
  var snickers = candies[1];

});


var promise = Candy.create({ type: 'jawbreaker' });
promise.then(function (jawbreaker) {

})

Model.watch()

参数

返回

• «ChangeStream» mongoose-specific change stream wrapper

Requires a replica set running MongoDB >= 3.6.0. Watches the underlying collection for changes using [MongoDB change streams.

This function does not trigger any middleware. In particular, it does not trigger aggregate middleware.

示例

const doc = await Person.create({ name: 'Ned Stark' });
Person.watch().on('change', change => console.log(change));





await doc.remove();

Model.insertMany()

参数

• [callback] «Function» callback

返回

Shortcut for validating an array of documents and inserting them into MongoDB if they're all valid. This function is faster than .create() because it only sends one operation to the server, rather than one for each document.

Mongoose always validates each document before sending insertMany to MongoDB. So if one document has a validation error, no documents will be saved, unless you set [the ordered option to false.

This function does not trigger save middleware.

This function triggers the following middleware.

示例

var arr = [{ name: 'Star Wars' }, { name: 'The Empire Strikes Back' }];
Movies.insertMany(arr, function(error, docs) {});

Model.bulkWrite()

参数

• [callback] «Function» callback function(error, bulkWriteOpResult) {}

返回

• «Promise» resolves to a BulkWriteOpResult if the operation succeeds

Sends multiple insertOne, updateOne, updateMany, replaceOne, deleteOne, and/or deleteMany operations to the MongoDB server in one command. This is faster than sending multiple independent operations (like) if you use create()) because with bulkWrite() there is only one round trip to MongoDB.

Mongoose will perform casting on all operations you provide.

This function does not trigger any middleware, not save() nor update(). If you need to trigger save() middleware for every document use [create() instead.

示例

Character.bulkWrite([
  {
    insertOne: {
      document: {
        name: 'Eddard Stark',
        title: 'Warden of the North'
      }
    }
  },
  {
    updateOne: {
      filter: { name: 'Eddard Stark' },



      update: { title: 'Hand of the King' }
    }
  },
  {
    deleteOne: {
      {
        filter: { name: 'Eddard Stark' }
      }
    }
  }
]).then(handleResult);

Model.hydrate()

参数

返回

• «Model» document instance

Shortcut for creating a new Document from existing raw data, pre-saved in the DB. The document returned has no paths marked as modified initially.

示例

var mongooseCandy = Candy.hydrate({ _id: '54108337212ffb6d459f854c', type: 'jelly bean' });

Model.update()

参数

返回

Updates one document in the database without returning it.

This function triggers the following middleware.

示例

MyModel.update({ age: { $gt: 18 } }, { oldEnough: true }, fn);
MyModel.update({ name: 'Tobi' }, { ferret: true }, { multi: true }, function (err, raw) {
  if (err) return handleError(err);
  console.log('The raw response from Mongo was ', raw);
});

有效的选项

• safe (boolean) safe mode (defaults to value set in schema (true))
• upsert (boolean) whether to create the doc if it doesn't match (false)
• multi (boolean) whether multiple documents should be updated (false)
• runValidators: if true, runs [update validators on this command. Update validators validate the update operation against the model's schema.
• setDefaultsOnInsert: if this and upsert are true, mongoose will apply the [defaults specified in the model's schema if a new document is created. This option only works on MongoDB >= 2.4 because it relies on [MongoDB's $setOnInsert operator.
• strict (boolean) overrides the strict option for this update
• overwrite (boolean) disables update-only mode, allowing you to overwrite the doc (false)

All update values are cast to their appropriate SchemaTypes before being sent.

The callback function receives (err, rawResponse).

• err is the error if any occurred
• rawResponse is the full response from Mongo

注释

All top level keys which are not atomic operation names are treated as set operations:

示例

var query = { name: 'borne' };
Model.update(query, { name: 'jason bourne' }, options, callback)


Model.update(query, { $set: { name: 'jason bourne' }}, options, callback)

This helps prevent accidentally overwriting all documents in your collection with { name: 'jason bourne' }.

注释

Be careful to not use an existing model instance for the update clause (this won't work and can cause weird behavior like infinite loops). Also, ensure that the update clause does not have an _id property, which causes Mongo to return a "Mod on _id not allowed" error.

注释

To update documents without waiting for a response from MongoDB, do not pass a callback, then call exec on the returned [Query:

Comment.update({ _id: id }, { $set: { text: 'changed' }}).exec();

注释

Although values are casted to their appropriate types when using update, the following are not applied:

• defaults
• setters
• validators
• middleware

If you need those features, use the traditional approach of first retrieving the document.

Model.findOne({ name: 'borne' }, function (err, doc) {
  if (err) ..
  doc.name = 'jason bourne';
  doc.save(callback);
})

Model.updateMany()

参数

返回

Same as update(), except MongoDB will update all documents that match criteria (as opposed to just the first one) regardless of the value of the multi option.

Note updateMany will not fire update middleware. Use pre('updateMany') and post('updateMany') instead.

This function triggers the following middleware.

Model.updateOne()

参数

返回

Same as update(), except MongoDB will update only the first document that matches criteria regardless of the value of the multi option.

This function triggers the following middleware.

Model.replaceOne()

参数

返回

Same as update(), except MongoDB replace the existing document with the given document (no atomic operators like $set).

This function triggers the following middleware.

Model.mapReduce()

参数

• [callback] «Function» optional callback

返回

Executes a mapReduce command.

o is an object specifying all mapReduce options as well as the map and reduce functions. All options are delegated to the driver implementation. See [node-mongodb-native mapReduce() documentation for more detail about options.

This function does not trigger any middleware.

示例

var o = {};
o.map = function () { emit(this.name, 1) }
o.reduce = function (k, vals) { return vals.length }
User.mapReduce(o, function (err, results) {
  console.log(results)
})

其他选项

• query {Object} query filter object.
• sort {Object} sort input objects using this key
• limit {Number} max number of documents
• keeptemp {Boolean, default:false} keep temporary data
• finalize {Function} finalize function
• scope {Object} scope variables exposed to map/reduce/finalize during execution
• jsMode {Boolean, default:false} it is possible to make the execution stay in JS. Provided in MongoDB > 2.0.X
• verbose {Boolean, default:false} provide statistics on job execution time.
• readPreference {String}
• out* {Object, default: {inline:1}} sets the output target for the map reduce job.

输出选项

• {inline:1} the results are returned in an array
• {replace: 'collectionName'} add the results to collectionName: the results replace the collection
• {reduce: 'collectionName'} add the results to collectionName: if dups are detected, uses the reducer / finalize functions
• {merge: 'collectionName'} add the results to collectionName: if dups exist the new docs overwrite the old

If options.out is set to replace, merge, or reduce, a Model instance is returned that can be used for further querying. Queries run against this model are all executed with the lean option; meaning only the js object is returned and no Mongoose magic is applied (getters, setters, etc).

示例

var o = {};
o.map = function () { emit(this.name, 1) }
o.reduce = function (k, vals) { return vals.length }
o.out = { replace: 'createdCollectionNameForResults' }
o.verbose = true;

User.mapReduce(o, function (err, model, stats) {
  console.log('map reduce took %d ms', stats.processtime)
  model.find().where('value').gt(10).exec(function (err, docs) {
    console.log(docs);
  });
})



o.resolveToObject = true;
var promise = User.mapReduce(o);
promise.then(function (res) {
  var model = res.model;
  var stats = res.stats;
  console.log('map reduce took %d ms', stats.processtime)
  return model.find().where('value').gt(10).exec();
}).then(function (docs) {
   console.log(docs);
}).then(null, handleError).end()

Model.aggregate()

参数

返回

Performs [aggregations on the models collection.

If a callback is passed, the aggregate is executed and a Promise is returned. If a callback is not passed, the aggregate itself is returned.

This function does not trigger any middleware.

示例

Users.aggregate(
  { $group: { _id: null, maxBalance: { $max: '$balance' }}},
  { $project: { _id: 0, maxBalance: 1 }},
  function (err, res) {
    if (err) return handleError(err);
    console.log(res);
  });


Users.aggregate()
  .group({ _id: null, maxBalance: { $max: '$balance' } })
  .select('-id maxBalance')
  .exec(function (err, res) {
    if (err) return handleError(err);
    console.log(res);
});

注释

• Arguments are not cast to the model's schema because $project operators allow redefining the "shape" of the documents at any stage of the pipeline, which may leave documents in an incompatible format.
• The documents returned are plain javascript objects, not mongoose documents (since any shape of document can be returned).
• Requires MongoDB >= 2.1

---

Model.geoSearch()

参数

• [callback] «Function» optional callback

返回

Implements $geoSearch functionality for Mongoose

This function does not trigger any middleware

示例

var options = { near: [10, 10], maxDistance: 5 };
Locations.geoSearch({ type : "house" }, options, function(err, res) {
  console.log(res);
});

选项

• near {Array} x,y point to search for
• maxDistance {Number} the maximum distance from the point near that a result can be
• limit {Number} The maximum number of results to return
• lean {Boolean} return the raw object instead of the Mongoose Model

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Model.populate()

参数

• [callback(err,doc)] «Function» Optional callback, executed upon completion. Receives err and the doc(s).

返回

Populates document references.

可用的选项

• path: space delimited path(s) to populate
• select: optional fields to select
• match: optional query conditions to match
• model: optional name of the model to use for population
• options: optional query options like sort, limit, etc

示例

User.findById(id, function (err, user) {
  var opts = [
      { path: 'company', match: { x: 1 }, select: 'name' }
    , { path: 'notes', options: { limit: 10 }, model: 'override' }
  ]

  User.populate(user, opts, function (err, user) {
    console.log(user);
  });
});


User.find(match, function (err, users) {
  var opts = [{ path: 'company', match: { x: 1 }, select: 'name' }]

  var promise = User.populate(users, opts);
  promise.then(console.log).end();
})










var user = { name: 'Indiana Jones', weapon: 389 }
Weapon.populate(user, { path: 'weapon', model: 'Weapon' }, function (err, user) {
  console.log(user.weapon.name)
})


var users = [{ name: 'Indiana Jones', weapon: 389 }]
users.push({ name: 'Batman', weapon: 8921 })
Weapon.populate(users, { path: 'weapon' }, function (err, users) {
  users.forEach(function (user) {
    console.log('%s uses a %s', users.name, user.weapon.name)


  });
});

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