How to develop a simple music recommendation function using MySQL and Ruby on Rails

How to use MySQL and Ruby on Rails to develop a simple music recommendation function, specific code examples are needed

With the continuous expansion of the music market and the increasing number of music varieties , it is difficult for users to find music that suits their tastes. Therefore, it is very necessary to develop a music recommendation function. This article will use the MySQL database and Ruby on Rails framework as the basis to introduce how to develop a simple music recommendation function and provide specific code examples.

Step One: Create Database
First, we need to create a MySQL database to store music data and user preferences. The following is an example Rails migration file used to create database tables:

class CreateSongs < ActiveRecord::Migration[6.0]
  def change
    create_table :songs do |t|
      t.string :title
      t.string :artist
      t.string :genre
    end
  end
end

class CreateUserPreferences < ActiveRecord::Migration[6.0]
  def change
    create_table :user_preferences do |t|
      t.references :user
      t.references :song
      t.integer :rating
    end
  end
end

The above code creates two tables: songs is used to store music information, including title (song title), artist (artist) and genre (music type); user_preferences is used to store the user's rating for each song.

Step 2: Model relationship and data filling
In Rails, we need to define the relationship between models. The following is the model code for the example:

class Song < ApplicationRecord
  has_many :user_preferences
  has_many :users, through: :user_preferences
end

class User < ApplicationRecord
  has_many :user_preferences
  has_many :songs, through: :user_preferences
end

class UserPreference < ApplicationRecord
  belongs_to :user
  belongs_to :song
end

The above code defines the relationship between Song, User and UserPreference. There is a many-to-many relationship between Song and User, and the connection is established through UserPreference.

Next, we need to fill in some sample data into the database. Here is the populating code for an example:

Song.create(title: 'Song 1', artist: 'Artist 1', genre: 'Pop')
Song.create(title: 'Song 2', artist: 'Artist 2', genre: 'Rock')
Song.create(title: 'Song 3', artist: 'Artist 3', genre: 'Jazz')

User.create(name: 'User 1')
User.create(name: 'User 2')
User.create(name: 'User 3')

UserPreference.create(user_id: 1, song_id: 1, rating: 4)
UserPreference.create(user_id: 1, song_id: 2, rating: 5)
UserPreference.create(user_id: 2, song_id: 2, rating: 3)
UserPreference.create(user_id: 3, song_id: 3, rating: 2)

The above code creates 3 songs, 3 users, and 4 user preference examples (user ratings of songs).

Step 3: Implement the music recommendation algorithm
Next, we need to implement a simple music recommendation algorithm. The following is an example recommendation algorithm:

class RecommendationController < ApplicationController
  def index
    user = User.find(params[:user_id])
    rated_songs = user.songs
    similar_users = User.where.not(id: user.id).joins(:songs)
                   .where('songs.id IN (?)', rated_songs.pluck(:id)).distinct
    recommended_songs = similar_users.joins(:songs).where.not('songs.id IN (?)', rated_songs.pluck(:id))
                       .group(:song_id).average(:rating)
    @recommendations = Song.where(id: recommended_songs.keys)
                       .order(recommended_songs.values.map(&:to_f).reverse)
  end
end

The above code defines a RecommendationsController controller, where the index method is based on the user's preference (i.e. the rating of the song) Calculate similar users and recommended songs and store the results in the @recommendations variable.

Step 4: Create a view
The last step is to create a view to display recommended songs. The following is a simple sample view code:

<h1>Recommendations for User <%= @user.name %></h1>

<% @recommendations.each do |song| %>
  <p><%= song.title %></p>
  <p>Artist: <%= song.artist %></p>
  <p>Genre: <%= song.genre %></p>
<% end %>

The above code displays a list of songs recommended to the user.

Summary:
This article introduces the steps to develop a simple music recommendation function using MySQL and Ruby on Rails. From creating databases and populating data, to defining model relationships and implementing recommendation algorithms, to creating views to display results. Hopefully this simple example will help readers understand how to develop music recommendation functionality using MySQL and Ruby on Rails.

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