Sequelize: effects of "unique" property in model definition

Question

I'm using Sequelize v3.5.1 with PostgreSQL v9.4.4 on a NodeJS server project.

In the model definition, it's not entirely clear to me what are the effects of adding the option unique: true to a property.

Let's take this code for example:

sequelize.define('User', {
  email: {
    type: Sequelize.STRING,
    unique: true
  },
  password: {
    type: Sequelize.STRING,
    allowNull: false
  }
});

Does this mean that PostgreSQL will build a unique index on email? So, is it just a shorthand method for this?

sequelize.define('User', {
  email: {
    type: Sequelize.STRING,
  },
  password: {
    type: Sequelize.STRING,
    allowNull: false
  }
}, {
  indexes: [
    {
      unique: true,
      fields: ['email']
    }
  ]
});

If so, will such index speed up table queries for email, or just ensure uniqueness?

Thanks!

Answer 1

A unique index will do both, it will speed up queries (as it has to create an index), and it will ensure that every value is unique.