将 SQL 查询转换为 Sequelize ORM 会返回不需要的结果

Question

我是 Sequelize 和 ORM 概念的初学者。我已成功将查询转换为 Sequelize findAll() 函数，但它返回不需要的结果。 PostgreSQL 查询可以正常工作并且返回结果非常好。

有关系的表：

1. writers(writerId PK, writerName)
2. 帖子（postId PK、postTitle、postDescription）
3. skillmatrix(skillmatrixId PK, writerId FK, postId FK, writerSkill)

我的查询：

SELECT writers."writerName", posts."postTitle", posts."postDescription", 
skillmatrix.* 
FROM writers
INNER JOIN skillmatrix
      ON writers."writerId" = skillmatrix."writerId"
INNER JOIN posts
      ON skillmatrix."postId" = posts."postId"
      ORDER BY writers."writerId", posts."postId"

SQL 查询的输出：

Sequelize 中的关系：

db.skillmatrix.hasMany(db.posts,{foreignKey: 'postId'});
db.skillmatrix.hasMany(db.writers,{foreignKey: 'writerId'});

Sequelize 中的 findAll() 方法：

exports.findAll = (req, res, next) => {
SkillMatrix.findAll({
    include: [
        {
            model: Writer,
            required: true
        },
        {
            model: Post, 
            required: true
        }
    ],
    order:[
        ['"writerId"', 'ASC'],
        ['"postId"', 'ASC']
    ]
})
.then(skillmatrix => {
    res.status(200).json(skillmatrix);
})
.catch(err => {
    console.log(err);
    res.status(500).json({msg: "error", details: err});
});
};

Sequelize 的 JSON 输出：

{
    "skillMatrixId": 1,
    "writerId": 1,
    "postId": 1,
    "writerSkill": "None",
    "writers": [
        {
            "writerId": 1,
            "writerName": "Writer1"
        }
    ],
    "posts": [
        {
            "postId": 1,
            "postTitle": "Post1"
            "postDescription": "This is Post1"
        }
    ]
},
{
    "skillMatrixId": 2,
    "writerId": 1,
    "postId": 2,
    "writerSkill": "SEO",
    "writers": [
        {
            "writerId": 2,
            "writerName": "Writer2"  //This is unexpected
        }
    ],
    "posts": [
        {
            "postId": 2,
            "postTitle": "Post2",
            "postDescription": "This is Post2"
        }
    ]
},
{
    "skillMatrixId": 3
    "writerId": 1,
    "postId": 3,
    "writerSkill": "Proofread"
    "writers": [
        {
            "writerId": 3,  //Unexpected
            "writerName": "Writer3" 
        }
    ],
    "posts": [
        {
            "postId": 3,
            "postTitle": "Post3",
            "postDescription": "This is Post3"
        }
    ]
}...

请告诉我，我做错了什么。还建议我一些很好的资源，我可以在其中深入学习。谢谢你。

编辑：

Sequelize 日志查询：

SELECT "skillmatrix"."skillMatrixId", 
"skillmatrix"."writerId", "skillmatrix"."postId",
"skillmatrix"."writerSkill", 
"writers"."writerId" AS "writers"."writerId",  
"writers"."writerName" AS "writers"."writerName", 
"posts"."postId" AS "posts"."postId", 
"posts"."postTitle" AS "posts"."postTitle", 
"posts"."postDescription" AS "posts"."postDescription", 
"posts"."writerId" AS "posts"."writerId"
FROM "skillmatrix" AS "skillmatrix" 
INNER JOIN "writers" AS "writers" ON "skillmatrix"."skillMatrixId" = 
"writers"."writerId" 
INNER JOIN "posts" AS "posts" ON "skillmatrix"."skillMatrixId" = 
"posts"."postId" 
ORDER BY "skillmatrix"."writerId" ASC, "skillmatrix"."postId" ASC

Answer 1

首先，您应该检查 sequelize 日志 - 您的 findAll 生成了什么查询？我猜它加入了错误的领域。

Sequelize 为多对多关系提供了一些选项。你可以试试：

db.posts.belongsToMany  (db.writers, {as : 'p2w', through: db.skillMatrix, foreignKey: 'postId'   });
db.writers.belongsToMany(db.posts,   {as : 'w2p', through: db.skillMatrix, foreignKey: 'writerId' });

db.posts.findAll({
  include: { 
     model: db.writers, 
     as: 'p2w',
     required: true
   }
});

我正在近似语法 - 请在文档中查看：belongsToMany

编辑 - 您现有的关联可以修复如下：

db.skillmatrix.hasMany(db.writers,{sourceKey: 'writerId', foreignKey: 'writerId'});

但是，请记住未来任务的 M:M 选项 :)

Answer 2

从以下位置更新 Sequelize 关系：

db.skillmatrix.hasMany(db.posts,{foreignKey: 'postId'});
db.skillmatrix.hasMany(db.writers,{foreignKey: 'writerId'});

到：

db.skillmatrix.hasMany(db.posts,{sourceKey: 'postId' , foreignKey: 'postId'});
db.skillmatrix.hasMany(db.writers,{sourceKey: 'writerId' ,foreignKey: 'writerId'});