Currently I learn to create restful api with golang and mongodb. Actually I am beginner in both. I use mongodb-go-driver and I learn to use filter when we want to use find()
function. But I have some that I don't understand. What is the different between filter := bson.M{"_id": "abcd"}
and filter := bson.M{{"_id": "abcd"}}
? Thank you
在golang mongodb中过滤
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- dtlab08822 2019-03-27 13:37关注
Refer to the source code, https://github.com/mongodb/mongo-go-driver/blob/master/bson/primitive/primitive.go
bson.D
, internally isprimitive.D
, which is[]primitive.E
, which is astruct
.bson.M
, internally isprimitive.M
, which ismap[string]interface{}
. You put in key/value inbson.M
but use document (struct) inbson.D
.It is better to explain it using 2 parameters, e.g. search for
a = 1 and b = 2
. You syntax will be:bson.M{"a": 1, "b": 2}
orbson.D{{"a": 1}, {"b": 2}}
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