node.js 使用 Sequelize 连接多个连接表
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25880539/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Join across multiple junction tables with Sequelize
提问by jtschoonhoven
I have a database with three primary tables: users, teams, and foldersjoined by two junction tables, users_teamsand teams_folders. There is a many-to-many relationship between users and teams and between teams and folders (a user can be on more than one team and teams can own more than one folder).
我有一个包含三个主表的数据库：users, teams,folders并由两个连接表连接，users_teams和teams_folders. 用户与团队之间以及团队与文件夹之间存在多对多关系（一个用户可以在多个团队中，而团队可以拥有多个文件夹）。
Sequelize does a wonderful job of managing the user-teams and teams-folder relationship, but I can find no way to establish a relationship between users and folders.
Sequelize 在管理用户-团队和团队-文件夹关系方面做得非常出色，但我找不到在用户和文件夹之间建立关系的方法。
Is there any way to join across two junction tables without resorting to raw SQL?
有没有办法在不使用原始 SQL 的情况下连接两个连接表？
There seems to be no way to accomplish this elegantly or in a reasonable number of steps. I have tried methods like user.getFolders(), Folder.findAll({ include: [User] }), but Sequelize doesn't seem to be able to understand a three level hierarchy.
似乎没有办法优雅地或以合理的步骤数来完成这一点。我尝试过像user.getFolders(), 之类的方法Folder.findAll({ include: [User] })，但是 Sequelize 似乎无法理解三级层次结构。
回答by Jan Aagaard Meier
Assuming the following relations:
假设以下关系：
User.belongsToMany(Team, { through: 'users_teams'});
Team.belongsToMany(User, { through: 'users_teams'});
Folder.belongsToMany(Team, { through: 'teams_folders'});
Team.belongsToMany(Folder, { through: 'teams_folders'});
You should be able to load everything in one go using nested includes:
您应该能够使用嵌套包含一次性加载所有内容：
User.findAll({
include: [
{
model: Team,
include: [
Folder
]
}
]
});
You seem to be on the right track already with the example you have given in your post :). The only thing you need to change is instead of passing the User model directly in include, you pass an object with a model property and a further nested include property
您似乎已经在您的帖子中给出的示例中走上了正确的轨道:)。您唯一需要更改的是，不是直接在 中传递 User 模型include，而是传递具有模型属性和进一步嵌套的包含属性的对象
回答by jmu
Pay attention to following:
注意以下几点：
- Define relations in both directions
- Check you have foreignKey, otherKey in correct order
- 定义双向关系
- 检查你有外键，其他键的顺序是否正确
User.belongsToMany(Team, {
through: 'users_teams',
foreignKey: 'user_id',
otherKey: 'team_id'
});
Team.belongsToMany(User, {
through: 'users_teams',
foreignKey: 'team_id',
otherKey: 'user_id'
});
