RethinkDB：​​Javascript - 如何删除嵌套对象 [英] RethinkDB: Javascript - How to deleted nested objects

问题描述

我在尝试从表中删除嵌套对象时遇到了相当大的困难，并且在此过程中没有意外删除我的所有数据（现在发生了三次，感谢上帝我制作副本）。

I'm having a rather large amount of difficulty with trying to remove nested objects from my table, without accidentally deleting all my data in the process (happened three times now, thank god I made copies).

我的对象：

{
  "value1": thing,
  "value2": thing,
  "value3": thing,
  "roles": {
    "1": {
      "name": "Dave",
      "id": "1"
    },
    "2": {
      "name": "Jeff",
      "id": "2"
    },
    "3": {
      "name": "Rick",
      "id": "3"
    },
    "4": {
      "name": "Red",
      "id": "4"
    }
  }
}`

我尝试了很多重新思考的查询，但到目前为止都没有。应该注意的是，1,2,3和& 4是可以包含任意数量的变量，因此我的查询必须反映出这一点。

I've tried a number of rethink queries, but none have worked thus far. It should be noted that 1, 2, 3, & 4 are variables that can have any amount of numbers, and thus my query must reflect that.

一些尝试的查询：

function removeRole(id, roleName) {
        let role = `${roleName}`
        return this.r.table('guilds').get(id).replace(function(s){
            return s.without({roles : {[role] : { "name": role }}})
        })
    }

function removeRole(id, roleName) {
        return this.r.table('guilds').getAll(id).filter(this.r.replace(this.r.row.without(roleName))).run()
    }

function removeRole(id, roleName) {
        return this.r.table('guilds').get(id)('roles')(roleName).delete()
    }

非常感谢任何帮助，如果问题是起诉，请告诉我。对此仍然相当新，所以反馈表示赞赏。

Any assistance is greatly appreciated, and if the question has issues, please let me know. Still rather new to this so feedback is appreciated.

推荐答案

我不确定我是否理解你的意图，但以下查询似乎正在做你想要完成的事情：

I'm not sure if I understood your intention, but the following query seems to do what you're trying to accomplish:

r.db('test')
  .table('test')
  .get(id)
  .replace((doc) => {
    // This expression makes sure that we delete the specified keys only
    const roleKeys = doc
      .getField('roles')
      .values()
      // Make sure we have a role name is in the names array
      .filter(role => r.expr(names).contains(role.getField('name')))
      // This is a bit tricky, and I believe I implemented this in a not efficient
      // way probably missing a first-class RethinkDB expression that supports
      // such a case out of box. Since we are going to delete by nested dynamic
      // ids, RethinkDB requires special syntax to denote nested ids:
      //     {roles: {ID_1: true, ID_2: true}}
      // Well, this is just a JavaScript syntax workaround, so we're building
      // such an object dynamically using fold.
      .fold({}, (acc, role) => acc.merge(r.object(role.getField('id'), true)));
    return doc.without({roles: roleKeys});
  })

例如，如果名称是一个数组，比如 ['Jeff'，'Rick'] ，嵌套的 roleKeys exssion将是动态评估为：

For example, if names is an array, say ['Jeff', 'Rick'], the nested roleKeys expession will be dynamically evaluated into:

{2: true, 3: true}

合并到 roles 选择器中，上面的查询将对文档进行如下转换：

that is merged into the roles selector, and the above query will transform the document as follows:

{
  "value1": ...,
  "value2": ...,
  "value3": ...,
  "roles": {
    "1": {"name": "Dave", "id": "1"},
    "4": {"name": "Red", "id": "4"}
  }
}

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