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Model

Model is a datastore-agnostic ORM in JavaScript. It serves as the model-component for the Geddy MVC Web framework for NodeJS.

License

Apache License, Version 2

Prerequisites

Model requires version 0.6.x of Node.js or higher. If you want to run the tests, or work on Model, you'll want the Jake JavaScript build-tool.

Installing with NPM

npm install model

Adapters

Model currently implements adapters for:

  • Postgres
  • Riak
  • MongoDB

Definining models

Model uses a pretty simple syntax for defining a model. (It should look familiar to anyone who has used an ORM like ActiveRecord, DataMapper, Django's models, or SQLAlchemy.)

var User = function () {
  this.property('login', 'string', {required: true});
  this.property('password', 'string', {required: true});
  this.property('lastName', 'string');
  this.property('firstName', 'string');

  this.validatesPresent('login');
  this.validatesFormat('login', /[a-z]+/, {message: 'Subdivisions!'});
  this.validatesLength('login', {min: 3});
  this.validatesConfirmed('password', 'confirmPassword');
  this.validatesWithFunction('password', function (s) {
      // Something that returns true or false
      return s.length > 0;
  });

  // Can define methods for instances like this
  this.someMethod = function () {
    // Do some stuff
  };
};

// Can also define them on the prototype
User.prototype.someOtherMethod = function () {
  // Do some other stuff
};

User = model.registerModel('User', User);

Abbreviated syntax

Alternatively, you can use the defineProperties method to lay out your model's properties in one go:

var User = function () {
  this.defineProperties({
    login: {type: 'string', required: true}
  , password: {type: 'string', required: true}
  , lastName: {type: 'string'}
  , firstName: {type: 'string'}
  });
}

Creating instances

Creating an instance of one of these models is easy:

var params = {
  login: 'alex'
, password: 'lerxst'
, lastName: 'Lifeson'
, firstName: 'Alex'
};
var user = User.create(params);

Validation and errors

Data-validation happens on the call to create, and any validation errors show up inside an errors property on the instance, keyed by field name. Instances have an isValid method that returns a Boolean indicating whether the instance is valid.

// Leaving out the required password field
var params = {
  login: 'alex'
};
var user = User.create(params);

// Prints 'false'
console.log(user.isValid());
// Prints 'Field "password" is required'
console.log(user.errors.password);

Saving items

After creating the instance, call the save method on the instance. This method takes a callbak in the familiar (err, data) format for Node.

if (user.isValid()) {
  user.save(function (err, data) {
    if (err) {
      throw err;
    }
    console.log('New item saved!');
  });
}

Updating items

Use the updateProperties method to update the values of the properties on an instance with the appropriate validations. Then call save on the instance.

user.updateProperties({
  login: 'alerxst'
});
if (user.isValid()) {
  user.save(function (err, data) {
    if (err) {
      throw err;
    }
    console.log('Item updated!');
  });
}

Querying

Model uses a simple API for finding and sorting items. Again, it should look familiar to anyone who has used a similar ORM for looking up records. The only wrinkle with Model is that the API is (as you might expect for a NodeJS library) asynchronous.

Methods for querying are static methods on each model constructor.

Finding a single item

Use the first method to find a single item. You can pass it an id, or a set of query parameters in the form of an object-literal. In the case of a query, it will return the first item that matches, according to whatever sort you've specified.

var user;
User.first({login: 'alerxst'}, function (err, data) {
  if (err) {
    throw err;
  }
  user = data;
  console.log('Found user');
  console.dir(user);
});

Collections of items

Use the all method to find lots of items. Pass it a set of query parameters in the form of an object-literal, where each key is a field to compare, and the value is either a simple value for comparison (equal to), or another object-literal where the key is the comparison-operator, and the value is the value to use for the comparison.

var users
  , dt;

dt = new Date();
dt.setHours(dt.getHours() - 24);

// Find all the users created since yesterday
User.all({createdAt: {gt: dt}, function (err, data) {
  if (err) {
    throw err;
  }
  users = data;
  console.log('Found users');
  console.dir(users);
});

Here are some more examples of queries:

// Where "foo" is 'BAR' and "bar" is not null
{foo: 'BAR', bar: {ne: null}}
// Where "foo" begins with 'B'
{foo: {'like': 'B'}}
// Where foo is less than 2112, and bar is 'BAZ'
{foo: {lt: 2112}, bar: 'BAZ'}

Comparison operators

Here is the list of comparison operators currently supported:

eql: equal to ne: not equal to gt: greater than lt: less than gte: greater than or equal lte: less than or equal like: like

A simple string-value for a query parameter is the same as 'eql'. {foo: 'bar'} is the same as {foo: {eql: 'bar'}}.

More complex queries

Model supports combining queries with OR and negating queries with NOT.

To perform an 'or' query, use an object-literal with a key of 'or', and an array of query-objects to represent each set of alternative conditions:

// Where "foo" is 'BAR' OR "bar" is 'BAZ'
{or: [{foo: 'BAR'}, {bar: 'BAZ'}]}
// Where "foo" is not 'BAR' OR "bar" is null OR "baz" is less than 2112
{or: [{foo {ne: 'BAR'}}, {bar: null}, {baz: {lt: 2112}}]}

To negate a query with 'not', simply use a query-object where 'not' is the key, and the value is the set of conditions to negate:

// Where NOT ("foo" is 'BAR' and "bar" is 'BAZ')
{not: {foo: 'BAR', bar: 'BAZ'}}
// Where NOT ("foo" is 'BAZ' and "bar" is less than 1001)
{not: {foo: 'BAZ', bar: {lt: 1001}}}

These OR and NOT queries can be nested and combined:

// Where ("foo" is like 'b' OR "foo" is 'foo') and NOT "foo" is 'baz'
{or: [{foo: {'like': 'b'}}, {foo: 'foo'}], not: {foo: 'baz'}}

Sorting

The all API-call for querying accepts an optional options-object after the query-conditions. Set a 'sort' in that options-object to specifiy properties to sort on, and the sort-direction for each one.

var users
// Find all the users who have ever been updated, and sort by
// creation-date, ascending, then last name, descending
User.all({updatedAt: {ne: null}}, {sort: {createdAt: 'asc', lastName: 'desc'}},
    function (err, data) {
  if (err) {
    throw err;
  }
  users = data;
  console.log('Updated users');
  console.dir(users);
});

Simplified syntax

You can use a simplified syntax for specifying the sort. The default sort-direction is ascending ('asc'), so you can specify a property to sort on (or multiple properties as an array) if you want all sorts to be ascending:

// Sort by createdAt, ascending
{sort: 'createdAt'}
// Sort by createdAt, then updatedAt, then lastName,
// then firstName -- all ascending
{sort: ['createdAt', 'updatedAt', 'lastName', 'firstName']}

Model JavaScript ORM copyright 2112 mde@fleegix.org.