MySql - Sequalize - Cannot add foreign key constraint

It's possible your char encoding is different between the foreign key and the original key. Check your schema.

If you need to turn off this check, because you're importing a bunch of tables from a dump from another DB, you want to run:

set FOREIGN_KEY_CHECKS=0

As if it was a SQL statement. So for me in Sequelize I ran:

let promise = sequelize.query("set FOREIGN_KEY_CHECKS=0");

This is because of mainly following 2 reasons

1. When the primary key data type and the foreign key data type did not match.

return sequelize.define('Manager', {
    id: {
      type: DataTypes.INTEGER(11), // The data type defined here and 
      references: {
        model: 'User',
        key: 'id'
      }
    }
  }
)

return sequelize.define('User', {
    id: {
      type: DataTypes.INTEGER(11),  // This data type should be the same
    }
  }
)

2. When the referenced key is not a primary or unique key.

return sequelize.define('User', {
        id: {
          primaryKey: true  
        },
        mail: {
            type: DataTypes.STRING(45),
            allowNull: false,
            primaryKey: true   // You should change this to 'unique:true'. you cant have two primary keys in one table. 
        }
    }
)

The order needs to change. You are creatig the wheel table before you have created the shop table. However wheel refers to the shop table which does not exists in your original set of queries. When you change the order the shop table already exists so the error does not occur.

CREATE TABLE IF NOT EXISTS `shop` 
 (`id` VARCHAR(255) NOT NULL , `accessToken` VARCHAR(255) NOT NULL, `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL, 
 PRIMARY KEY (`id`)) ENGINE=InnoDB;


CREATE TABLE IF NOT EXISTS `wheel` 
(`id` INTEGER NOT NULL auto_increment , `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL, `shopId` VARCHAR(255), 
 PRIMARY KEY (`id`), 
 FOREIGN KEY (`shopId`) REFERENCES `shop` (`id`) ON DELETE SET NULL ON UPDATE CASCADE) ENGINE=InnoDB;

CREATE TABLE IF NOT EXISTS `segments` 
(`segmentID` VARCHAR(255) NOT NULL , `heading` VARCHAR(255) NOT NULL, `subHeading` VARCHAR(255) NOT NULL, `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL, `wheelId` INTEGER, 
 PRIMARY KEY (`segmentID`),
 FOREIGN KEY (`wheelId`) REFERENCES `wheel` (`id`) ON DELETE SET NULL ON UPDATE CASCADE) ENGINE=InnoDB;