Agfdhyk

i'm implementing a like system for a project. And I need some help with a query.

Basically i have 2 buttons (upvote and downvote) that call my function and give the id of a thread, the username voting, and the vote ( 1 or -1).

addPositiveorNegativeLikes = function(thread_id, username, vote) {



 sequelize.query('INSERT INTO Likes (thread_id, userId, vote, createdAt, updatedAt) 

 VALUES((?), (SELECT id FROM Users WHERE username=(?)), (?), (?), (?)) 

 ON DUPLICATE KEY UPDATE thread_id=(?), userId=(SELECT id FROM Users WHERE username=(?))',{



 replacements: [thread_id, username, vote, new Date(), new Date(), thread_id, username]

 }) 

}

But now in my Likes table althought thread_id and userId ara both primary keys, inserts multiple repeated "Likes".

How I can modify my query so it deletes an existing vote and replaces it for a new one??

Here is my Like model:

'use strict';

module.exports = (sequelize, DataTypes) => {

const Like = sequelize.define('Like', {

  id: {

      allowNull: false,

      autoIncrement: true,

      primaryKey: true,

      type: DataTypes.INTEGER

  },

  userId: {

      allowNull: false,

      primaryKey: true,

      type: DataTypes.INTEGER

  },

  thread_id: {

      allowNull: false,

      primaryKey: true,

      type: DataTypes.INTEGER

  },

  createdAt: {

      allowNull: false,

      type: DataTypes.DATE

  },

  updatedAt: {

      allowNull: false,

      type: DataTypes.DATE

  },

  vote: {

      type: DataTypes.INTEGER

  }

}, {});

 Like.associate = function(models) {

 // associations can be defined here

 };

return Like;

};

Here , what you can do is , create a composite key , with this

userId: {

    allowNull: false,

    unique:"vote_user" // <------ HERE

    type: DataTypes.INTEGER

},

thread_id: {

    allowNull: false,

    unique:"vote_user" // <------ HERE

    type: DataTypes.INTEGER

},

NOTE :

 // Creating two objects with the same value will throw an error. The unique property can be either a

 // boolean, or a string. If you provide the same string for multiple columns, they will form a

 // composite unique key.

 uniqueOne: { type: Sequelize.STRING,  unique: 'compositeIndex' },

 uniqueTwo: { type: Sequelize.INTEGER, unique: 'compositeIndex' },

And then create it like :

Like.create({ userId : 1 , thread_id : 1 }).then(data => {

    // success

}).catch(err => {

    // error if same data exists

})

// <--- this will check that if there any entry with userId 1 and thread_id 1 , 

// if yes , then this will throw error

// if no then will create an entry for that

Note :

Never never run raw query , like you have did in your code sample , always use the model to perform CRUD , this way you can utilize all
the features of sequelizejs