Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.0k views
in Technique[技术] by (71.8m points)

node.js - Node - associate tables with Sequelize

I'm trying to associate tables in such a way that:

  • A group has many documents
  • A document belongs to a group
  • A group belongs to an user
  • An user has many groups

When i try to list all from table 'Group' including 'User', throws an error saying that User is not associated to Group.

My models:

Document.js

const Document = conn.define('document', {
    title: {
        type: Sequelize.TEXT,
        allowNull: false
    },
    content: {
        type: Sequelize.TEXT,
        allowNull: false
    },
    footer: {
        type: Sequelize.TEXT,
    }

})

Document.sync()
Document.associate = (models) => {
    Document.belongsTo(models.Group, {foreignKey: 'groupId', as: 'Group'})
}

module.exports = Document

Group.js

const Group = conn.define('group', {
    name: {
        type: Sequelize.STRING,
        allowNull: false
    },
})

Group.sync()
Group.associate = (models) => {
    Group.hasMany(models.Document, {foreignKey: 'groupId', as: 'Document'})
    Group.belongsTo(models.User, {foreignKey: 'userId', as: 'User'})
}

module.exports = Group

User.js

const User = conn.define('user', {
    firstName: {
        type: Sequelize.STRING,
        allowNull: false
    },
    lastName: {
        type: Sequelize.STRING,
        allowNull: false
    },
    email: {
        type: Sequelize.STRING,
    },
    password: {
        type: Sequelize.STRING
    },
})

User.sync()
User.associate = (models) => {
    User.hasMany(models.Group, {foreignKey: 'groupId', as: 'Group'})
}

module.exports = User
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

I see one mistake in your code. You should use the same foreign key name for one to many relationships. Otherwise you will have two different columns in your database.

Here you should use userId as foreign key. Sequelize creates the id column in "belongsTo" model. So there will be a userId in Group model if you use it like this:

User.hasMany(models.Group, {foreignKey: 'userId', as: 'Group'});
Group.belongsTo(models.User, {foreignKey: 'userId', as: 'User'});

Also try not creating the associations in model files. Consider using index.js files and you can create all of your associations in there.

src
    app.js
    models
        index.js
        user.js
        group.js
        document.js

Keep you model definition in their files. Export the created model classes. Include them in your index.js file. Create necessary associations and export them again.

src/models/index.js

const User = require('./user');
const Group = require('./group');
const Document = require('./document');

User.hasMany(models.Group, {foreignKey: 'userId', as: 'Group'});
Group.belongsTo(models.User, {foreignKey: 'userId', as: 'User'});

// Define what associations you need.

module.exports = {
    User,
    Group,
    Document
};

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...