Insert Array inside an object in MongoDB

Question

I am new at MongoDB and I want to insert to mongodb data like this but I couldn\'t figure out how

{
  image = \"cab\"
  tags = [
            [ \"NNP\", 0 ],
             


        

Answer 1

Basically you use BasicDBObject for key-value mappings and BasicDBList for array objects. For the object in your question, you'd do this:

BasicDBList dbl = new BasicDBList();
dbl.add(new BasicDBObject("NNP",0));
dbl.add(new BasicDBObject("NN", 1));
BasicDBOBject outer=new BasicDBObject("image", "cab").append("tags", dbl);

There's some convenience methods in the api to make this a bit less verbose.

The mapping works like this:

for:  {"A":1}  use: new BasicDBObject("A",1)
for: {"A":1, "B":2}  use: new BasicDBObject("A",1).append("B",2)
for: {"A":{"B":2}}  use: new BasicDBObject("A",new BasicDBObject("B",2))
for: {"A":["B","C"]} use:
        BasicDBList dbl = new BasicDBList();
        dbl.add("B");
        dbl.add("C");
         ->  new BasicDBObject("A",dbl);