将文档从一个集合移动到另一个集合会覆盖文档

Question

第一个操作是匹配id[1602271]，创建新的集合并保存一个文档（下面提到的文档）。

{
  "_id": "1602271",
  "date": "2019-02-11T06:25:13.425Z",
  "currentStatus": "scheduled",
  "statusHistory": [
    {
      "status": "onboarded",
      "date": "2018-11-02T10:07:11.167Z"
    },
    {
      "status": "preference_ready",
      "date": "2018-11-02T10:08:56.359Z"
    },
    {
      "status": "scheduled",
      "date": "2018-11-02T10:26:38.721Z"
    }
  ]
}

对于第二个操作 id[1602131]，它不会创建新文档，而是用旧文档覆盖（JSON 以上）。

{
  "_id": "1602131",
  "date": "2019-01-22T07:08:58.253Z",
  "currentStatus": "scheduled",
  "statusHistory": [
    {
      "status": "onboarded",
      "date": "2018-11-02T06:07:28.765Z"
    },
    {
      "status": "preference_ready",
      "date": "2018-11-02T06:11:30.777Z"
    },
    {
      "status": "scheduled",
      "date": "2018-11-29T05:48:57.871Z"
    }
  ]
}

请参考以下代码：

  public static final String STATUS_COLLECTION_NAME = "TeacherStatus";

  public static final String ARCHIVE_STATUS_COLLECTION_NAME = 
                "ArchiveTeacherStatus";

    Aggregation aggregation = Aggregation.newAggregation(match(where("_id").is(teacherId)),
                    out(ARCHIVE_STATUS_COLLECTION_NAME));
            mongoOperations.aggregate(aggregation, STATUS_COLLECTION_NAME, TeacherStatus.class);

Answer 1

按预期工作。 https://docs.mongodb.com/manual/reference/operator/aggregation/out/

If the collection specified by the $out operation already exists, then upon completion of the aggregation, the $out stage atomically replaces the existing collection with the new results collection.

在 mongodb 4.2 中，$out 阶段将接受一个附加参数 mode，它可以取值 "replaceCollection"（现在发生了什么），"replaceDocuments", "insertDocuments" (你想要什么).

有了 re-read 你的代码，你为什么要使用 聚合管道 和 $out 来复制一个文件？那是用大炮打麻雀

您可以通过该应用程序更可靠地做到这一点。阅读文档，然后保存到其他collection.

将文档从一个集合移动到另一个集合会覆盖文档

Move document from one collection to another is overwriting the document

java

mongodb

aggregation-framework

spring-data-mongodb