sequelize - Cannot add foreign key constraint

Question

I'm trying to set a 1:1 relation between two tables. RefreshToken table will have two foreignKey releated to Users table, as in this image:

I used sequelize-auto to generate my sequelize models.

Users model:

module.exports = function(sequelize, DataTypes) {
  return sequelize.define('Users', {
    idUsers: {
      type: DataTypes.INTEGER(11),
      allowNull: false,
      primaryKey: true
    },
    name: {
      type: DataTypes.STRING(45),
      allowNull: true
    },
    mail: {
      type: DataTypes.STRING(45),
      allowNull: false,
      primaryKey: true
    }
  }, {
    tableName: 'Users'
  });
};

RefreshToken model:

module.exports = function(sequelize, DataTypes) {
  return sequelize.define('RefreshToken', {
    idRefreshToken: {
      type: DataTypes.INTEGER(11),
      allowNull: false,
      primaryKey: true
    },
    token: {
      type: DataTypes.TEXT,
      allowNull: true
    },
    userId: {
      type: DataTypes.INTEGER(11),
      allowNull: false,
      primaryKey: true,
      references: {
        model: 'Users',
        key: 'idUsers'
      }
    },
    userEmail: {
      type: DataTypes.STRING(45),
      allowNull: false,
      primaryKey: true,
      references: {
        model: 'Users',
        key: 'mail'
      }
    }
  }, {
    tableName: 'RefreshToken'
  });
};

When I run the application, I receive this error:

Unhandled rejection Error: SequelizeDatabaseError: ER_CANNOT_ADD_FOREIGN: Cannot add foreign key constraint

I tried to add explicit the relation, adding in Users table:

User.associate = (models) => {
    User.hasOne(models.RefreshToken, {
      foreignKey: 'userId'
    });
    User.hasOne(models.RefreshToken, {
      foreignKey: 'userEmail'
    });
  };

and in RefreshToken:

RefreshToken.associate = (models) => {
    RefreshToken.belongsTo(models.Users, {
      foreignKey: 'userId'
    });
    RefreshToken.belongsTo(models.Users, {
      foreignKey: 'userEmail'
    });
  };

But I receive again the same error. If I remove the references in the RefreshToken table I don't see any error, but when I check the database I don't see any foreign key relation constraint with email and id of the User

Try to use only userid as foreign key in RefreshToken table. — matrix
Or you should use Composite Foreign keys: stackoverflow.com/questions/9780163/… — matrix
Here is information that Composite foreign keys are not supported in sequelize.js: github.com/sequelize/sequelize/issues/311 — matrix

bereket gebredingle bereket gebredingle · Accepted Answer · 2018-09-23T22:45:49

This is common type error mainly occurs because of

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

return sequelize.define('RefreshToken', {
    userId: {
      type: DataTypes.INTEGER(11), // The data type defined here and 
      references: {
        model: 'Users',
        key: 'idUsers'
      }
    }, 


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

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

You can not have two primary keys, so other referenced keys should be defined unique. unique:true

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

sequelize - Cannot add foreign key constraint

2 Answers

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

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