joli.js, a light js ORM for Appcelerator Titanium

Presentation of joli.js

joli.js is a simple ORM for Appcelerator Titanium mobile projects. It was built borrowing large parts of the code of JazzRecord, a more general and complex javascript ORM. Praise and kudos to them!

joli.js is widely unit-tested. Go check the demo application in order to run the test suite.

What does "joli" stand for?

"joli" means in French "nice", "tiny". Just what joli.js tries to be.

Download and install

The source code of joli.js is available on GitHub. Just grab it and include it in your Titanium project using either Titanium.include() or the CommonJS require()statement:

Titanium.include('joli.js');

or (please note the missing ".js" suffix):

var joli = require('path/to/joli').connect('your_database_name');

The latter integration mode must be prefered, as it helps sandboxing external libraries. Loading joli.js with require() will also allow to use several databases in the same application, which is not possible with Ti.include():

var joliLibrary = require('path/to/joli');
var database1 = joliLibrary.connect('first_database');
var database2 = joliLibrary.connect('second_database');

It is also possible to install existing databases bundled with the application:

var joli = require('path/to/joli').connect('your_database_name', '/path/to/database.sqlite');

Configuration

Database connection creation

If you included joli.js with Titanium.include(), there is one single required configuration step: configuring the database name. This can be done in only one line, which has to be put before every call to joli.js's API:

joli.connection = new joli.Connection('your_database_name');

If you prefered to load joli.js as a CommonJS module, it is not necessary to write this configuration instruction. However, you still may want to change the database name of a connection, and in that case you'll want to use this command.

Models configuration

Prior inserting data and querying your models, you must declare these models. This is done by instantiating the class "joli.model":

var city = new joli.model({
  table:    'city',
  columns:  {
    id:                 'INTEGER',
    name:               'TEXT',
    description:        'TEXT'
  }
});

If your application uses a lot of models, I advice to bind all of these in a models variable, which will contain every models:

var models = (function() {
  var m = {};

  m.human = new joli.model({
    table:    'human',
    columns:  {
      id:                 'INTEGER PRIMARY KEY AUTOINCREMENT',
      city_id:            'INTEGER',
      first_name:         'TEXT',
      last_name:          'TEXT'
    },
    methods: {
      countIn:  function(cityName) {
        // search for the city id
        var city = joli.models.get('city').findOneBy('name', cityName);

        if (!city) {
          throw 'Could not find a city with the name ' + cityName + '!';
        } else {
          return this.count({
            where: {
              'city_id = ?': city.id
            }
          });
        }
      }
    },
    objectMethods: {
      move:  function(newCityName) {
        // search for the city id
        var city = joli.models.get('city').findOneBy('name', newCityName);

        if (!city) {
          throw 'Could not find a city with the name ' + newCityName + '!';
        } else {
          this.set('city_id', city.id);
        }
      }
    }
  });

  m.city = new joli.model({
    table:    'city',
    columns:  {
      id:                 'INTEGER PRIMARY KEY AUTOINCREMENT',
      country_id:         'INTEGER',
      name:               'TEXT',
      description:        'TEXT'
    }
  });

  m.country = new joli.model({
    table:    'country',
    columns:  {
      id:                 'INTEGER PRIMARY KEY AUTOINCREMENT',
      name:               'TEXT'
    }
  });

  return m;
})();

The parameters array, which allows to configure a model, may contain several keys:

• table: the table name,
• columns: the name of the various columns proposed by the model. For each of them, it is required to specify their type (INTEGER, TEXT or FLOAT),
• methods: a table of class-level methods, in order to extend the model (see the countIn method upper). Note: these methods will be added to the model definition, not its instances,
• objectMethods: a table of object-level methods, which allow to extend the model instances (see the move method upper).

Usage

This section describes the way on how to use joli.js.

Tables initialisation

At the first launch of an application on a device, it is required to create the tables associated with the models, with the required fields. Of course, joli.js helps initialising the database: simple call the joli.models.initialize() method once the models have been defined:

var city = new joli.model({
  table:    'city',
  columns:  {
    id:                 'INTEGER',
    name:               'TEXT',
    description:        'TEXT'
  }
});

joli.models.initialize();

Would you like the "id" to get auto-incremented, just add the informations "PRIMARY KEY AUTOINCREMENT" to the column definition :

var city = new joli.model({
  table:    'city',
  columns:  {
    id:                 'INTEGER PRIMARY KEY AUTOINCREMENT',
    name:               'TEXT',
    description:        'TEXT'
  }
});

Data insertion

Inserting data can be done using the newRecord() method of a model:

// create the record (not persisted)
var john = models.human.newRecord({
  first_name: 'John',
  last_name: 'Doe'
});

// move him to New York
john.move('New York');

// persist it
john.save();

You may also want to create a record using the instance class directly:

var john = new joli.record(models.human);
john.fromArray({
  first_name: 'John',
  last_name: 'Doe'
});

// move him to New York
john.move('New York');

// persist it
john.save();

The first method is however advised, as it performs some checks on the existence of the columns.

Data retrieval and Query API

Retrieving data is often a pain. For all the models, joli.js implements some magic finders in the model classes:

• findBy(field, value) allows to retrieve a list of the records having a specific value for one of its fields
• findById(id) allows to retrieve a list of the records having a specific id
• findOneBy(field, value) allows to retrieve one record having a specific value for one of its fields. If several records match the criteria, then only the first one will be returned
• findOneById(id) allows to retrieve one record having a specific id

But of course, you will want to perform more complex searches. This is where the query API enters in the dance. This query API allows to create joli.query objects, which are turned into real SQL queries by the ORM when executing the query.

This is particularly powerful when you want to add restrictions to the query in conditional statements:

var q = new joli.query()
  .select('human.*')
  .from('human')
  .order(['last_name desc', 'first_name asc']);

if (win.city_id) {
  q.where('city_id = ?', win.city_id);
}

if (win.last_name) {
  q.where('last_name LIKE ?', '%' + win.last_name + '%');
}

if (win.city_name) {
  q.where('city.name = ?', win.city_name);
  q.join('city', 'city.id', 'human.city_id');
}

var humans = q.execute();

The Query API supports lots of things. Just have a check at the joli.query class, or look at the samples provided in the joli.query test suite!

For instance, the following query syntaxes are supported by the API:

var q = new joli.query()
  .select()
  .from('human')
  .whereIn('last_name', [ 'Doe', 'Smith' ]);


var q = new joli.query()
  .select()
  .from('view_count')
  .where('nb_views between ? and ?', [1000, 2000]);

In some cases however, you will find this way of querying your models just too long, and you will prefer an other alternative syntax (Criteria-style querying API):

var humans = models.human.all({
  where: {
    'city_id = ?': win.city_id
  },
  order: ['last_name desc', 'first_name asc']
});

Data retrieval for queries with no specific model (eg, GROUP BY)

Some query results can't be mapped back to a Joli model. For example, when using a GROUP BY statement:

SELECT city, COUNT(*) as count
FROM human
GROUP BY city

The rows returned by the above query are not Joli models, but simple [city, count] tuples.

To avoid having Joli try to map the query results to a model, you can pass a string parameter "array" to the .execute() function to have the results returned as an array of simple objects:

var q = new joli.query()
    .select('city, COUNT(*) as count')
    .from('human')
    .groupBy('city')
    .execute("array");

Internals

joli.js is made of several classes:

• joli, which is a convenience class for storing utilities,
• joli.Connection, which handles the real connection to the database,
• joli.model, which allows to perform some operations on a model,
• joli.Models, which acts as a hashmap of the models, and allows to initialise the database,
• joli.query, allows to write queries in a OOP style,
• and, finally, joli.record represents a record and contains useful methods.

You may want to override some of these classes for your convenience (for instance, for implementing an automatic synchronisation with a REST web service)... Just feel free to contribute back your changes!

Howtos

This section gives some clues about how to use joli.js. It will be updated when questions will be sent to me about joli.js.

Lost the tables reference

Would you have a specific part of your code where your models can not be accessed using the models object, it is still possible to access it using the method joli.models.get(). In other words:

models.human == joli.models.get('human');

Are there demo joli.js applications in the wild?

There are at the moment three open source applications using joli.js:

• xavccMobileApp is an url shortening application which uses joli.js for storing shortened urls in a local cache;
• joli.js-demo is a demo application, which contains the unit-tests for joli.js;
• joli.api.js-demo is an Iphone Addressbook-like application, which content gets synchronized with web services. This application was built in a couple of hours and was presented a a demo app at CodeStrong in 2011.

Use several databases in the same application

It is possible to use several databases with joli.js by loading the library as a CommonJS module:

var joliLibrary = require('path/to/joli');
var database1 = joliLibrary.connect('first_database');
var database2 = joliLibrary.connect('second_database');

Credits and support

joli.js has been developed by Xavier Lacot and is licensed under the MIT license. The joli.js project is sponsored by JoliCode.

Please use GitHub in order to report bugs, but you may also ask for help on how to use joli.js by sending me a mail directly. My email address is [email protected].

Changelog

Master

• added the replace() for building queries (thanks benjaminVadon)

Version 0.4 - 2012-06-21

• turned joli.js as a commonjs module
• added the possibility to install an existing database bundled with the app
• added a as() method for building queries with join() (thanks nicjansma)
• fixed a bug in the query where() method, when a value was 0 or '' (thanks nicjansma)
• added a toArray() method on record instances
• fixed missing semicolon (jslint inside)
• adding optional migration callback to make migrations more general in usage (thanks Anthony Roldan)
• updated the documentation

Version 0.3 - 2011-07-22

• added a lot of unit tests in the demonstration application. Most ORM features are now unit-tested.
• selection now return object collections
• added support for several hydratation modes
• joli.js now validates through jshint
• introduced joli.model.truncate(), which empties the table associated to a model
• introduced joli.record.get(), which allows to acces one record's properties
• made joli.query.join() able to complete the joined field names in the format table.field
• fixed joli.query.whereIn() which was buggy for textual values
• fixed a variable-reference bug in joli.record.save(), which led to an inconsistent behavior of joli.record.isChanged()

Version 0.2 - 2011-06-20

• added object-level methods, and fixed the documentation accordingly

Version 0.1 - 2010-11-15

Initial public release. Features a simple ActiveRecord implementation, along with an OOP query API.