递归包括Sequelize？ [英] Recursive include Sequelize?

问题描述

我有可以拥有子类别的类别

I have category that can have child categories

当我在做findAll我想要包括所有那些嵌套，但我不知道深度。

And when I'm doing findAll I want to include all of those nested, but I don't know the depth.

var includeCondition = { 
                         include: [
                            { 
                               model: models.categories,
                               as:'subcategory', nested: true 
                            }]
                       };

models.categories.findAll(includeCondition)
        .then(function (categories) {
            resolve(categories);
        })
        .catch(function (err) {
            reject(err);
        })
});

结果只给我一个级别的嵌套包含。

The result brings me only one level nested include.

[  
   {  
      dataValues:{  

      },
      subcategory:{  
         model:{  
            dataValues:{  

            }
            // no subcategory here            
         }
      }
   }
]

我可以以某种方式使sequalize包括那些嵌套的子类别吗？

Can I somehow make sequalize include those nested subcategories ?

推荐答案

如果找到这个
的解决方案很少，第一个更复杂但会提供更好的性能：

There are few solutions if found for this first one is more complicated but will give better performance:

这个是关于在MySQL中实现分层数据结构
我喜欢这里的指南

This one is about implementing hierarchical data structure in MySQL I like the guide here

http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/

名为The Nested Set Mod的那个el。

The one that is named The Nested Set Model.

我自己实际实现的第二个解决方案是递归扩展，这个使用了很多mysql请求，我相信可以改进，但它是一个快速的，效果很好。事情是用于这样的每个类别函数

The second solution that I actually implemented by myself is recursive expanding, this one uses lots of mysql requests and I believe can be improved, but it's a fast one and works well. The thing is to use for each category function like this

var expandSubcategories = function (category) {
    return new promise(function (resolve, reject) {
        category.getSubcategories().then(function (subcategories) {
            //if has subcategories expand recursively inner subcategories
            if (subcategories && subcategories.length > 0) {
                var expandPromises = [];
                _.each(subcategories, function (subcategory) {
                    expandPromises.push(expandSubcategories(subcategory));
                });

                promise.all(expandPromises).then(function (expandedCategories) {
                    category.subcategories = [];

                    _.each(expandedCategories, function (expandedCategory) {
                        category.subcategories.push(expandedCategory);
                    }, this);


                    //return self with expanded inner
                    resolve(category);
                });

            } else {
                //if has no subcategories return self
                resolve(category);
            }
        });
    });
};

所以它会通过类别并递归扩展它们。

So it's going through the categories and expanding them recursively.

也许这对某人也有帮助。

Maybe this will help someone as well.

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