> small.find({},

)
{
"_id" : ObjectId("4ad394773dbdf53293f6c58a"),
"prop1" : "men"
}
> small.find({},{_id:1,prop1:1})
{
"_id" : ObjectId("4ad394773dbdf53293f6c589")
}
{
"_id" : ObjectId("4ad394773dbdf53293f6c58a"),
"prop1" : "men"
}
{
"_id" : ObjectId("4ad394773dbdf53293f6c58b")
}
> small.find({},

)
{
"_id" : ObjectId("4ad394773dbdf53293f6c58a"),
"prop1" : "men"
}