modeloespecial.lua

An ORM for Corona SDK based on Backbone.js

local User = Model:extend {table = 'users'}
function User:fullName()
  return self:get('firstName') .. ' ' .. self:get('lastName')
end

local user = User:new {firstName = 'John', lastName = 'Doe'}
user:fullName() -- John Doe
user:save()

user:set {firstName = 'Foo', lastName = 'White'}
user:save()

Fair warning: This is a work in progress, but expect fast updates as we use this on our games.

Installing

With bower

Generate a project using corona-bower and then install this library with

bower install --save modeloespecial

Manually

Download the zip containing all files on the Releases tab

Initialize

Instantiate a ModeloEspecial instance

local ModeloEspecial = require 'vendor.modeloespecial.modeloespecial'
local Model = ModeloEspecial.Model

local db = ModeloEspecial:new {name = 'database'}

ModeloEspecial:new receives the following parameters

• name (required) the name of the database
• location (default: system.DocumentsDirectory) the location of the database
• debug (default: false) log to the database all executed sql queries
• migration see below.

A special case is when location equals "memory". This will create an in-memory instance of sqlite.

Migrations

You can create tables and version the schema of the database.

This way, even if a game user has an old version of the database, we can get it to the current version.

local function createUsers(schemaVersion, exec)
  if schemaVersion < 1 then
    exec('CREATE TABLE users(name VARCHAR, color INTEGER)')
  end
  return 1
end
db:migrate(createUsers)

Migration functions receive the following parameters

• schemaVersion (number) the current schema version
• exec (function(sql)) a function to execute the given sql.

Models

Model:extend()

Create a new model

local User = Model:extend {table = 'users'}

Model:extend receives an table with the following possible parameters

• table (required) The name of the table
• attrs The attributes that this table has. By default ModeloEspecial will explore the table and get all columns
• idAttribute The name of the unique identifier in the table. default: 'ROWID'

model:save()

saves or updates a model to the database

local user = User:new {name = 'Foo', color = 'orange'}
user:save() -- executes: INSERT INTO users(name, color) VALUES ('Foo', 'orange')

user:set('name', 'Bar')
user:save() -- executes: UPDATE users SET name='Bar' WHERE ROWID=1

model:get()

gets an attribute from a model

local user = User:new {name = 'Foo'}
user:get 'name' -- 'Foo'

It receives

• attribute - name of the attribute

model:set()

sets and attribute for a model and marks it to change on the next update

local user = User:new()
user:set('name', 'Foo')
user:set {color = 'red'}

It can receive either

• attribute name of the attribute
• value value of the attribute

or

• changes a table with the desired attribute changes

Model:fetchById()

Finds a user by the id

local user = User.fetchById(1)

Model:fetchBy()

Finds a user by the specified params

local user = User.fetchBy {name = 'Foo'}

Model.defaults

Sets default values for attributes

User.defaults = {
  color = 'red'
}
local user = User:new()

user:get'color' -- 'red'

Model events

Before persisting changes, a saving event is emitted. Also, either an updating or creating event will be emitted.

If a listener to this events throws an error then the model will not be persisted and Model:save() will return false

local function hasLastName(self)
  if not self:get('lastName') then
    error('No last name was specified')
  end
end
User:on('saving', hasLastName)

Also any changes done to self on the event handlers are persisted

local function validateStates(self)
  local state = self:get('state')
  if state == 'CA' then
    self:set {state = 'California'}
  end
end

Changelog

• 0.0.3 Adds creating, created, saving, saved, updating and updated events
• 0.0.2 Adds defaults