问题描述
我具有这种结构，旨在通过Sequelize实现多态多对多关联中的渴望加载。
赋予选项 include 时，它返回意外结果（例如不属于此标签的食谱和帖子）
模型
// Food model
Food.belongsToMany(models.Tag,{
through: {
model: "tag_taggable",unique: false,scope: { taggable_type: "food" }
},foreignKey: "taggable_id",constraints: false
});
// Recipe model
Recipe.belongsToMany(models.Tag,scope: { taggable_type: "recipe" }
},constraints: false
});
// Post model
Post.belongsToMany(models.Tag,scope: { taggable_type: "post" }
},constraints: false
});
// Tag model
Tag.belongsToMany(models.Food,unique: false
// scope: { taggable_type: "food" }
},foreignKey: "tag_id",constraints: false
});
Tag.belongsToMany(models.Recipe,unique: false
// scope: { taggable_type: "recipe" }
},constraints: false
});
Tag.belongsToMany(models.Post,unique: false
// scope: { taggable_type: "post" }
},constraints: false
});
Tag.prototype.getTaggables = async function (options) {
const recipes = await this.getRecipe(options);
const foods = await this.getFood(options);
const posts = await this.getPost(options);
return posts.concat(recipes).concat(foods);
}
// Tag_Taggable junction model
const TagTaggable = sequelize.define(
"TagTaggable",{
id: { type: DataTypes.BIGINT,primaryKey: true,autoIncrement: true },tag_id: { type: DataTypes.BIGINT,unique: "tt_unique_constraint" },taggable_id: { type: DataTypes.BIGINT,unique: "tt_unique_constraint",references: null },taggable_type: { type: DataTypes.STRING,}
);
数据库
可标记记录：
+----+--------+-------------+---------------+---------------------------+
| id | tag_id | taggable_id | taggable_type | |
+----+--------+-------------+---------------+---------------------------+
| 1 | 1 | 1 | food | fast,hamburger |
+----+--------+-------------+---------------+---------------------------+
| 2 | 1 | 1 | recipe | fast,Caesar Salad Recipe |
+----+--------+-------------+---------------+---------------------------+
| 3 | 1 | 2 | food | fast,bacon |
+----+--------+-------------+---------------+---------------------------+
| 4 | 2 | 1 | post | fresh,Post 1 |
+----+--------+-------------+---------------+---------------------------+
| 5 | 2 | 2 | recipe | fresh,french Salad Recipe |
+----+--------+-------------+---------------+---------------------------+
| 6 | 2 | 3 | recipe | fresh,Greek Salad Recipe |
+----+--------+-------------+---------------+---------------------------+
查询
查询＃1：查找所有标签，包括与其相关联的（食物，帖子，食谱），并加载它们
const tags = await Tag.findAll({
include: [
{ model: db["Food"] /*,required: true*/ },{ model: db["Post"] /*,{ model: db["Recipe"] /*,]
});
return tags[0]; // first tag found
预期：仅出现食物（“汉堡”，“培根”）和食谱（“凯撒沙拉食谱”）。
{ id:1,name:"fast",foods: [ {hamburger},{bacon} ],recipes: [ {caesar salad recipe} ],posts: [] }
[
0: {
id: 1,name: "fast",foods: [
{
name: "hamburger",taggable_id: 1,tag_id: 1
},{
name: "bacon",taggable_id: 2,tag_id: 1
}
],recipes: [
{
name: "Caesar Salad Recipe",{
name: "french Salad Recipe",posts: [
{
name: "Post 1",{
name: "Post 2",tag_id: 1
}
]
}
]
意外的＃1
包括相关模型时，范围似乎不影响内部联接（taggable_type看起来像被忽略）。
如果我在tags0上调用getTaggables，我会在数组中获得预期的项目（但是这并不急于加载）
tags[0].getTaggables() // => [ {hamburger},{bacon},{caesar salad recipe} ]
const food = await Food.findOne({
where: { id: 2 },include: [
{
model: db["Tag"] // required: true
}
]
});
预期
{ id:2,name:"bacon",tags:[ {fast} ] }
{
id: 2,name: "bacon",tags: [
{
name: "fast",tag_taggable: {
taggable_id: 2,tag_id: 1
}
},{
name: null
tag_taggable: {
taggable_id: 2,tag_id: 2
}
}
]
意外＃2
它在Tag include中包含了错误的模型（其在标签中包含 recipe ），显示为null（某种程度上是其配方）
sql
查询＃1 正在生成的错误SQL查询之一： Tag.include（Food，Recipe，Post）
SELECT
`Tag`.`id`,`Tag`.`name`,`Tag`.`color`,`Tag`.`created_at` AS `createdAt`,`Tag`.`updated_at` AS `updatedAt`,`foods`.`id` AS `foods.id`,`foods`.`name` AS `foods.name`,`foods->tag_taggable`.`taggable_id` AS `foods.tag_taggable.taggable_id`,`foods->tag_taggable`.`tag_id` AS `foods.tag_taggable.tag_id`,`recipes`.`name` AS `recipes.name`,`recipes->tag_taggable`.`taggable_id` AS `recipes.tag_taggable.taggable_id`,`recipes->tag_taggable`.`tag_id` AS `recipes.tag_taggable.tag_id`
FROM
`tag` AS `Tag`
LEFT OUTER JOIN `tag_taggable` AS `foods->tag_taggable`
ON `Tag`.`id` = `foods->tag_taggable`.`tag_id`
LEFT OUTER JOIN `food` AS `foods`
ON `foods`.`id` = `foods->tag_taggable`.`taggable_id`
LEFT OUTER JOIN `tag_taggable` AS `recipes->tag_taggable`
ON `Tag`.`id` = `recipes->tag_taggable`.`tag_id`
LEFT OUTER JOIN `recipe` AS `recipes`
ON `recipes`.`id` = `recipes->tag_taggable`.`taggable_id`;
LEFT OUTER JOIN `tag_taggable` AS `post->tag_taggable`
ON `Tag`.`id` = `posts->tag_taggable`.`tag_id`
LEFT OUTER JOIN `post` AS `posts`
ON `posts`.`id` = `posts->tag_taggable`.`taggable_id`;
查询＃2 生成的第二个错误的SQL查询： Food.include（Tag）
SELECT
`Food`.`id`,`Food`.`name`,`tags`.`id` AS `tags.id`,`tags`.`name` AS `tags.name`,`tags->tag_taggable`.`taggable_id` AS `tags.tag_taggable.taggable_id`,`tags->tag_taggable`.`tag_id` AS `tags.tag_taggable.tag_id`
FROM
`food` AS `Food`
LEFT OUTER JOIN `tag_taggable` AS `tags->tag_taggable`
ON `Food`.`id` = `tags->tag_taggable`.`taggable_id`
LEFT OUTER JOIN `tag` AS `tags`
ON `tags`.`id` = `tags->tag_taggable`.`tag_id`
AND `tags->tag_taggable`.`taggable_type` = 'food' WHERE `Food`.`id` = 2;
包裹
"sequelize": "^6.3.4","sequelize-cli": "^6.2.0","sqlite3": "^5.0.0",我如何处理这个模型，包括急切的装载情况？
解决方法
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