RethinkDB：​​Javascript - 如何删除嵌套对象

Question

我在尝试从我的表中删除嵌套对象时遇到了很大的困难，而在此过程中不会意外删除我的所有数据（现在发生了 3 次，感谢上帝我复制了）。

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"
    }
  }
}`

我尝试了许多重新思考的查询，但到目前为止都没有奏效。需要注意的是 1、2、3 和 4 是可以有任意数量的数字的变量，因此我的查询必须反映这一点。

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，如果问题有问题，请告诉我。对此仍然相当新，因此感谢您的反馈。

Answer 1

我不确定我是否理解您的意图，但以下查询似乎可以完成您想要完成的工作：

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names 是一个数组，比如['Jeff', 'Rick']，则嵌套的roleKeys 表达式将被动态评估为：

{2: true, 3: true}

即被合并到roles 选择器中，上面的查询将转换文档如下：

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