What's the $unwind operator in MongoDB?

Question

This is my first day with MongoDB so please go easy with me :)

I can\'t understand the $unwind operator, maybe because English is not my native language

Answer 1

consider the below example to understand this Data in a collection

{
        "_id" : 1,
        "shirt" : "Half Sleeve",
        "sizes" : [
                "medium",
                "XL",
                "free"
        ]
}

Query -- db.test1.aggregate( [ { $unwind : "$sizes" } ] );

output

{ "_id" : 1, "shirt" : "Half Sleeve", "sizes" : "medium" }
{ "_id" : 1, "shirt" : "Half Sleeve", "sizes" : "XL" }
{ "_id" : 1, "shirt" : "Half Sleeve", "sizes" : "free" }