Duplicate index on a column

[alphanso]

Hi,
I am using knex for my project.

exports.up = function(knex, Promise) {
  return knex.schema.createTable('users', function (t) {
    t.increments();

    // Database authenticatable
    t.string('email').notNullable().unique().index();
    t.string('encrypted_password').notNullable();

    // Recoverable
    t.string('reset_password_token').unique().index();
    t.dateTime('reset_password_sent_at');

    // Rememberable
    t.dateTime('remember_created_at');

    // Trackable
    t.integer('sign_in_count').notNullable().defaultTo(0);
    t.dateTime('current_sign_in_at');
    t.dateTime('last_sign_in_at');
    t.specificType('current_sign_in_ip', 'inet');
    t.specificType('last_sign_in_ip', 'inet');

    // Confirmable
    // t.string('confirmation_token').unique().index();
    // t.dateTime('confirmed_at');
    // t.dateTime('confirmation_sent_at');
    // t.string('unconfirmed_email');  // Only if using reconfirmable

    // Lockable
    // t.integer('failed_attempts').defaultTo(0).notNullable(); // Only if lock strategy is 'failed_attempts'
    // t.string('unlock_token').unique().index(); // Only if unlock strategy is 'email' or 'both'
    // t.dateTime('locked_at')

    t.timestamps();
  });
};

This migration creates total of 5 indexes.
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
"users_email_unique" UNIQUE CONSTRAINT, btree (email)
"users_reset_password_token_unique" UNIQUE CONSTRAINT, btree (reset_password_token)
"users_email_index" btree (email)
"users_reset_password_token_index" btree (reset_password_token)

[WhiteCat6142]

console.log(
knex.schema.createTable("x",function(table){
    table.string("name").unique().index();
})
.toString());

Result:
create table "x" ("name" varchar(255));
create unique index x_name_unique on "x" ("name");
create index x_name_index on "x" ("name")

Forget turn off the regular index?

[WhiteCat6142]

oh,I realize that unique() create unique index automatically.

console.log(
knex.schema.createTable("x",function(table){
    table.string("name").unique();
})
.toString());

Result:
create table "x" ("name" varchar(255));
create unique index x_name_unique on "x" ("name")