allow null value for sequelize foreignkey?
I am no expert on node.js nor sequelize.js, but with one search in google I got the official documentation. You might need to pay some attention to this part of the code in the documentation:
Library.hasMany(Picture, { foreignKey: { name: 'uid', allowNull: false }});It seems you need to specify the {foreignKey: {name: 'bookId', allowNull: true} } in Library.
By default, the Sequelize association is considered optional. If you would like to make the foreign key required, you can set allowNull to be false.
Foo.hasOne(Bar, { foreignKey: { allowNull: false }});