How to fetch values from double mapping?

Question

I have a structure data with double mapping for storing and fetching details. Here is the code :

struct data {
    uint a;
    uint b;
}
mapping(address => mapping(bytes11 => data[])) testidmapping;

Used storevalues() function to store and getvalues() to fetch the values

function storevalues(address owner,bytes11 id,uint a,uint b) public{
testidmapping[owner][id].push(data(a,b));
}

function getvalues(address owner,bytes11 id) view returns (uint a){
  data storage k = testidmapping[owner][id];
  return (k.a);

}

Is this the possible way of double mapping for fetching and storing details? But I am getting this error:

BigNumber() is not a number: (id is printing)

Help will be appreciated...

Answer 1

As you intended to access an attribute of an arraydata[] you shall provide an index. You might also need a length of an array data so that you can write a loop in backend code to retrieve all the a's stored in an array data.

Refer the following function -

function getValuesAtIndex(address owner,bytes11 id,uint dataindex) view returns (uint a){

  return (testidmapping[owner][id][dataindex].a);

}

function getDataLength(address owner,bytes11 id)view returns(uint){

  return (testidmapping[owner][id].length);    
}

Hope it helps! Let me know if any further clarification is required.