Stop providing a default `id` attribute for models

The default id that Sequelize provides for models is often source of confusion.

const Foo = sequelize.define('foo', {
  name: DataTypes.STRING
});

Is actually equivalent to

const Foo = sequelize.define('foo', {
  id: {
    type: DataTypes.INTEGER,
    allowNull: false,
    primaryKey: true,
    autoIncrement: true
  },
  name: DataTypes.STRING
});

It has the obvious advantage of less boilerplate code. However, it is often source of confusion and weird errors, such as in issue #11723 (as clarified in this comment) and #11714

I suggest a breaking change of no longer providing this default attribute. Let’s make users define them. This way this kind of confusion will never happen.

[soryy708]

The feature of auto-generating the id column is indeed useful for minimizing boilerplate, but it does cause various problems. The type of problems caused touch on many sequelize subsystems and tend to be complicated edge cases. Fixing all of the issues caused by the auto-generated id column may require a lot of effort. Removing the id column auto-generation would mean a breaking API change, but the effort required for migration is very small (and perhaps can be automated with a tool). This issue was open since 2016, and it looks like no one’s in opposition to the removal.

[soryy708]

That’s a good idea @Keimeno . To maintain backwards compatibility, generatePrimaryKey will be true by default (current behaviour). We can then print a warning to the log if generatePrimaryKey isn’t explicitly present, s.t. a version later we can change the API to make it false by default.