foreign key constraint error

I’m not super great with MySQL yet so im struggling with why this is happening. I had everything working fine and then I dropped the DB to start fresh and now the code no longer works. Here’s the error"

2015-09-12 23:03:16 12d144000 Error in foreign key constraint of table app/comments:
FOREIGN KEY (`post_id`) REFERENCES `posts` (`id`) ON DELETE SET NULL ON UPDATE CASCADE) ENGINE=InnoDB:
You have defined a SET NULL condition though some of the
columns are defined as NOT NULL.

Here’s the SQL it’s trying to inject:

CREATE TABLE IF NOT EXISTS `posts` (`id` CHAR(36) BINARY , `title` VARCHAR(255) NOT NULL, `body` TEXT NOT NULL, `slug` TEXT, `cover_photo` TEXT, `created_at` DATETIME, PRIMARY KEY (`id`)) ENGINE=InnoDB;

SHOW INDEX FROM `posts`

CREATE TABLE IF NOT EXISTS `comments` (`id` CHAR(36) BINARY , `post_id` CHAR(36) BINARY NOT NULL, `body` TEXT NOT NULL, `created_at` DATETIME, PRIMARY KEY (`id`), FOREIGN KEY (`post_id`) REFERENCES `posts` (`id`) ON DELETE SET NULL ON UPDATE CASCADE) ENGINE=InnoDB;

Here’s my model definitions

var Sequelize = require('sequelize');
var orm = require('../utils/orm');
var Comments = require('./comment');

var Post = orm.define('post', {
  id: {
    type: Sequelize.UUID,
    defaultValue: Sequelize.UUIDV4, // Generates a UUID V4
    primaryKey: true
  },
  title: {
    type: Sequelize.STRING, // Should cap titles to 255 characters
    allowNull: false
  },
  body: {
    type: Sequelize.TEXT,
    allowNull: false
  },
  slug: {
    type: Sequelize.TEXT, // URLs can be any length
    allowNull: true
  },
  cover_photo: {
    type: Sequelize.TEXT, // URLs can be any length
    allowNull: true
  },
  created_at: {
    type: Sequelize.DATE,
    defaultValue: Sequelize.NOW
  }
}, {
  timestamps: false,
  underscored: true
});

Post.hasMany(Comments);
Comments.belongsTo(Post);

module.exports = Post;

var Sequelize = require('sequelize');
var orm = require('../utils/orm');

var Comment = orm.define('comment', {
  id: {
    type: Sequelize.UUID,
    defaultValue: Sequelize.UUIDV4, // Generates a UUID V4
    primaryKey: true
  },
  post_id: {
    type: Sequelize.UUID,
    allowNull: false
  },
  body: {
    type: Sequelize.TEXT,
    allowNull: false
  },
  created_at: {
    type: Sequelize.DATE,
    defaultValue: Sequelize.NOW
  }
}, {
  timestamps: false,
  underscored: true
});

module.exports = Comment;

I read in another post to try flipping the associations around, but it didn’t help. I tried flipping it to:

Comments.belongsTo(Post);
Post.hasMany(Comments);

[angelxmoreno]

I had something similar happen to me. I simply removed the foreign keys from the model definition and let the associations create it for me. When you attach associations Sequelize will create those foreign keys for you. I think the error is that they already exist because you defined them in the model. Try removing the post_id column from Comments model. Please let us know if it works.

[tamil-03]

I too faced these same issues, Thanks for the Solution