MongoDB数据批量更新的问题

{
    "_id" : ObjectId("522d9783974929f816000000"),
    "N" : "3301",
    "S" : {
        "L" : 373,
        "W" : 210,
        "H" : 82
    },
    "M" : "面料：麻料",
    "I" : [
        "http://l300img.b0.upaiyun.com/lb40_gallary/3301.jpg"
    ],
    "T" : [
        {
            "N" : "单人位",
            "L" : 80,
            "W" : 101,
            "H" : 82,
            "V" : 0.6626,
            "P" : 580
        },
        {
            "N" : "单人位",
            "L" : 80,
            "W" : 101,
            "H" : 82,
            "V" : 0.6626,
            "P" : 580
        },
        {
            "N" : "带扶单位",
            "L" : 110,
            "W" : 101,
            "H" : 82,
            "V" : 0.911,
            "P" : 730
        },
        {
            "N" : "转角位",
            "L" : 101,
            "W" : 101,
            "H" : 82,
            "V" : 0.8365,
            "P" : 680
        },
        {
            "N" : "贵妃位",
            "L" : 110,
            "W" : 101,
            "H" : 82,
            "V" : 0.911,
            "P" : 680
        }
    ],
    "O" : false
}

单条数据如上所示，我需要将所有的P:数据值更改为P:[数据值]，整个文档所有数据都需要改。

---

db.table_name.find().forEach(function (x){T = x['T'];for (i in T){T[i]['P'] = [T[i]['P'],]};db.table_name.save(x)})