node.js - Sequelize 模型 - 删除 belongsToMany n :m association 的项目

Question

我正在尝试为我的应用程序设置一个 DELETE 路由，它使用带有 Postgres 数据库的 Sequelize。我有两个不同的模型，“产品”和“兴趣”(将兴趣视为一种类别或标签)。 Products can have multiple Interests and Interests can have multiple Products,所以我使用的是belongsToMany关联。因此，我有三个表:Products、Interests 和 ProductInterests。以下是我如何设置关联:

对于产品:

Product.belongsToMany(models.Interest, {
    foreignKey: 'productId',
    through: models.ProductInterest,
    as: 'interests',
    onDelete: 'CASCADE',
    hooks: true
});

对于兴趣:

Interest.belongsToMany(models.Product, {
    through: models.ProductInterest,
    as: 'products',
    foreignKey: 'interestId',
    onDelete: 'CASCADE',
    hooks: true
});

这是在我的产品 Controller 中调用的方法:

destroy(req, res) {
    return Product
        .findById(req.params.productId, {
            include: [
                {
                    association: Product.associations.interests
                }
            ]
        })
        .then((product) => {
            if (!product) {
                return res.status(404).send({
                    message: 'Product not found'
                });
            }
            return product
                .destroy()
                // I've also tried the following:
                // .destroy({
                //    truncate: true,
                //    cascade: true
                // })
                .then(() => res.status(204).send())
                .catch(error => res.status(400).send(error));
        })
        .catch(error => res.status(400).send(error));

这会导致无限循环，并记录这些查询:

Executing (default): SELECT "Product"."id", "Product"."title", "Product"."brand", "Product"."url", "Product"."imageUrl", "Product"."currentPrice", "Product"."male", "Product"."female", "Product"."asin", "Product"."storeName", "Product"."createdAt", "Product"."updatedAt", "ProductInterest"."createdAt" AS "ProductInterest.createdAt", "ProductInterest"."updatedAt" AS "ProductInterest.updatedAt", "ProductInterest"."interestId" AS "ProductInterest.interestId", "ProductInterest"."productId" AS "ProductInterest.productId" FROM "Products" AS "Product" INNER JOIN "ProductInterests" AS "ProductInterest" ON "Product"."id" = "ProductInterest"."productId" AND "ProductInterest"."interestId" = 1;
Executing (default): SELECT "Interest"."id", "Interest"."name", "Interest"."createdAt", "Interest"."updatedAt", "ProductInterest"."createdAt" AS "ProductInterest.createdAt", "ProductInterest"."updatedAt" AS "ProductInterest.updatedAt", "ProductInterest"."interestId" AS "ProductInterest.interestId", "ProductInterest"."productId" AS "ProductInterest.productId" FROM "Interests" AS "Interest" INNER JOIN "ProductInterests" AS "ProductInterest" ON "Interest"."id" = "ProductInterest"."interestId" AND "ProductInterest"."productId" = 6;

我的意图是 a) 删除 Product 表中的产品； b) 删除 ProductInterest 表中的关联记录。如果正在删除产品，我不希望删除兴趣本身。同样，如果兴趣被删除(只是关联)，我不希望删除关联的产品。

我已经围绕这个尝试了几种不同的排列，但找不到正确的方法。任何帮助将不胜感激。

更新

稍微调试一下 sequelize 代码让我认为我不应该那样使用 cascade。它基本上是在尝试删除产品，然后(由于级联)尝试删除兴趣(我不想要)，然后(由于级联)尝试删除相关产品，等等。仍然不确定是什么正确的解决方案是。

Answer 1

首先，belongsToMany 的默认行为是删除它的级联，写在 DOCS 中。

For 1:1 and 1:m associations the default option is SET NULL for deletion, and CASCADE for updates. For n:m, the default for both is CASCADE. This means, that if you delete or update a row from one side of an n:m association, all the rows in the join table referencing that row will also be deleted or updated.

但我认为在创建表创建或迁移中创建外键引用时明确编写它是行不通的，如下所示:

queryInterface.createTable('ProductInterest', {
  productId: {
    type: Sequelize.INTEGER,
    references: {
        model: 'Product',
        key: '_id',
      },
    onDelete: 'cascade'
  },
  interestId: {
    type: Sequelize.INTEGER,
    references: {
        model: 'Interest',
        key: '_id',
      },
    onDelete: 'cascade'
  },
});