sanderhouttekier/sequelizedemo

simple user-tasks app

setup basic express app

• mkdir sqldemo
• cd sqldemo
• npm install express express-generator
• node_modules/.bin/express . -f
• npm install

init & config sequelize

• npm install --save sequelize sequelize-cli sqlite3
• sequelize init

will generate models dir, config dir, and migrations dir

• edit config/config.json

"development": {
  "dialect": "sqlite",
  "storage": "./sqldemo-dev.sqlite"
},

create some models

sequelize model:create --name User --attributes "username:string"
sequelize model:create --name Task --attributes "title:string, completed:boolean"

migrations

mention how migrations are automatically added when creating new models via this CLI and how limited that is. Manual adding of migrations is needed for every change until something can generate em for us.

relations

first all entities are created, then assosiations are added

available:

• hasOne
• belongsTo
• hasMany
• belongsToMany

back to our example

User.hasMany(models.Task);
Task.belongsTo(models.User);

a hasMany:

• adds User.tasks if you include the model in your query (population)
• adds User.getTasks(), User.setTasks() on the model
• adds User.removeTask(), User.removeTasks() on the model
• adds User.addTask(), User.addTasks() on the model

while, a belongsTo:

• adds Task.user if you include the user model in your query (population)
• adds Task.setUser(), Task.getUser() on the model.

ORM

create / update

User
  .create({ username: 'fnord' })
  .then(function() {

  });

find & findAll

User
    .find(1)
    .then(function(user){
        // do stuff;
    });
// is same as
User
    .find({ where: { id: 1 } })
    .then(function(user){
        // do stuff
    });

// finding more than 1
Task
    .findAll({ where: { completed: false } })
    .then(function(tasks){
        // do stuff with the array of tasks
    });

findOrCreate

var newUser = { username: 'myNewUser' };
User
    .findOrCreate({
        where: { username: newUser.username },
        defaults: newUser;
    })
    .spread(function(m, created){
        // do stuff
    });

a lot more:

http://sequelize.readthedocs.org/en/latest/docs/models/#data-retrieval-finders

what did i not touch but is also possible:

• validation
• bulk create
• expanding model with methods .getFullName
• expanding model with custom setters and getters
• finding with counts or other ma(d)(th) science
• errorhandling .catch()
• .spread() vs .then()
• eager loading
• ...