Question

所以我有一个这样的mongo文档，我需要根据val

更新数组

{
"_id" : NumberLong(222),
"pattern":"grain"
"BASIC" : {
    "frame":"clear"
    "tin" : [ 
        {
            "val" : "abc",
            "unit" : NumberLong(2311)
        }, 
        {
            "val" : "def",
            "unit" : NumberLong(2311)
        }, 
    ]
}
}

这是我试过的代码

        collection = db.getCollection("test");
    Bson where = new Document().append("_id", 222).append("BASIC.tin.val","abc");

     Bson update = new Document()
                .append("BASIC.tin.$.val", "xyz");
     Bson set = new Document().append("$set", update);
        try {

            UpdateResult result = collection.updateOne(where , set, new UpdateOptions().upsert(true));

            if(result.getMatchedCount()>0){
                System.out.println("updated");
                System.out.println(result.getModifiedCount());
            }else{
                System.out.println("failed");
            }
        } catch (MongoWriteException e) {
          e.printStackTrace();
        }

更新工作正常但如果查找失败则不会upsert 这是我得到的错误：

com.mongodb.MongoWriteException：位置运算符未找到查询所需的匹配项。未更新的更新：BASIC.tin。$。val 在com.mongodb.MongoCollectionImpl.executeSingleWriteRequest（MongoCollectionImpl.java:558）在com.mongodb.MongoCollectionImpl.update（MongoCollectionImpl.java:542）

Answer 1

嵌入文档中的upsert是不可能的，因此错误。因此，要模拟嵌入式文档的upsert，您需要更新代码，如下所示。这将检查修改后的计数，如果为0则表示我们需要在嵌入式文档中插入一个新文档，该文档使用了push。对于您拥有的示例文档，这将以“pqr”作为val并将“unit”作为400进行upsert。

Bson where = new Document().append("_id", 222).append("BASIC.tin.val","pqr");

Bson update = new Document()
        .append("BASIC.tin.$.val", "xyz");
Bson set = new Document().append("$set", update);

try {

    UpdateResult result = collection.updateOne(where , set, new UpdateOptions());

    if(result.getModifiedCount() > 0){
        System.out.println("updated");
    } else if(result.getModifiedCount()==0){
          System.out.println("upserting");
          Bson where1 = new Document().append("_id", 222);
          Bson upsert = new Document().append("BASIC.tin", new Document().append("val", "pqr").append("unit", 400));;
          Bson push = new Document().append("$push", upsert);
          UpdateResult result1 = collection.updateOne(where1 , push, new UpdateOptions());
          if(result1.getModifiedCount() == 1)
              System.out.println("upserted");
    }else {
        System.out.println("failed");
    }
} catch (MongoWriteException e) {
  e.printStackTrace();
}

upsert后的示例响应

{
    "_id": NumberLong(222),
    "pattern": "grain",
    "BASIC": {
        "frame": "clear",
        "tin": [{
            "val": "xyz",
            "unit": NumberLong(2311)
        }, {
            "val": "def",
            "unit": NumberLong(2311)
        }, {
            "val": "pqr",
            "unit": 400
        }]
    }
}

在MongoDB中更新嵌套数组文档

1 个答案: