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Arrays 如何将对象前置到数组的顶部位置?_Arrays_Mongodb_Position_Push_Prepend - Fatal编程技术网

Arrays 如何将对象前置到数组的顶部位置?

Arrays 如何将对象前置到数组的顶部位置?,arrays,mongodb,position,push,prepend,Arrays,Mongodb,Position,Push,Prepend,如果我在MongoDb文档中有以下数组: "example": { [ "number": 5, "someValue": "V" ], [ "number": 7, "someValue": "H" ] } 如何将下面的数组添加到上面的数组的顶部: [ "number": 3, "someValue": "S" ] 使原始数组变成: "example": { [

如果我在MongoDb文档中有以下数组:

"example": {
    [
        "number": 5,
        "someValue": "V"
    ],
    [
        "number": 7,
        "someValue": "H"
    ]
}
如何将下面的数组添加到上面的数组的顶部:

[
     "number": 3,
     "someValue": "S"
]
使原始数组变成:

"example": {
    [
        "number": 3,
        "someValue": "S"
    ],
    [
        "number": 5,
        "someValue": "V"
    ],
    [
        "number": 7,
        "someValue": "H"
    ]
}

您可以使用以下
$push
操作符的选项来实现这一点:

db.collection.update({},
{  
   $push:{  
      "arr":{  
         $each:[  
            {  
               "number": 3,
               "someValue": "S"
            }
         ],
         $position: 0
      }
   }
})
$position
指定将插入元素的位置