dounanyin3179 2018-01-25 15:55
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mongodb update添加每个地图结构的值

There is a map data {"a": 2, "c": 4: "d": 0}, and a document in MongoDB:

{
    ...
    Score: {
        "a": 1,
        "b": 2,
        "c": 0,
    }
}

The updated document:

{
    ...
    Score: {
        "a": 3,
        "b": 2,
        "c": 4,
        "d": 0,
    }
}

Is what I wanted, now this works well:

bson.M{"$inc": bson.M{"Score.a": 2,....}},

How can I use a map without knowing its keys to update the document in MongoDB? Map to struct? Or use MongoDB .map function?

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  • douyi4205 2018-01-25 16:04
    关注

    If you have the map value, you know its keys, you can loop over them, and build the "dynamic" update document manually.

    This is how it could look like:

    m := map[string]int{
        "a": 2,
        "c": 4,
        "d": 0,
    }
    
    incDoc := bson.M{}
    for k, v := range m {
        incDoc["Score."+k] = v
    }
    updateDoc := bson.M{"$inc": incDoc}
    

    Printing the result with

    fmt.Printf("%#v
    ", updateDoc)
    

    Output would be:

    bson.M{"$inc":bson.M{"Score.d":0, "Score.a":2, "Score.c":4}}
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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