Relationship between mongodb documents

12 Relationship between documents

one-on-one

Embedded document form

Relatively few

db.wifeAndHusband.insert([{
	name:" Huang Rong ",
	husband:{
		name:" Guo Jing "
	}
}])

One to many

user –》 Order

db.order.insert({

	list:[" beef "," comic "],
	user_id:ObjectId("hhjhdfgjk");
})


// Find user swk The order of 
var user_id=db.users.findOne({username:"swk"})._id;
db.order.find({user_id:user_id});

Many to many

db.teacher.insert([
    
    {
    name:" Common wife Palace "},
    {
    name:" Tortoise Fairy "}
]);

db.stus.insert([
    {
    
        name:" Guo Jing ",
        tech_ids:[
            ObjectId("kkkk"),
            ObjectId("djslgkdj")
        ]
    }
]);