i am working on supply chain DApps .here i want to add budget with ownername only not with the whole block

Question

    type Product struct {
    ID        string `json:"id"`
    Name      string `json:"name"`
    Area      string `json:"area"`
    OwnerName string `json:"ownerName"`
    Value     int    `json:"cost"`
    Budget    int    `json:"budget"`
}
func (pc *ProductTransferSmartContract) AddProduct(ctx contractapi.TransactionContextInterface, id string, name string, area string, ownerName string, cost int, budget int) error {

    productJSON, err := ctx.GetStub().GetState(id)
    if err != nil {
        return fmt.Errorf("Failed to read the data from world state", err)
    }

    if productJSON != nil {
        return fmt.Errorf("the product %s already exists", id)
    }

    prop := Product{
        ID:        id,
        Name:      name,
        Area:      area,
        OwnerName: ownerName,
        Value:     cost,
    }

    productBytes, err := json.Marshal(prop)
    if err != nil {
        return err
    }

    return ctx.GetStub().PutState(id, productBytes)
}

here i want to attach budget only with owner name so that if owner got changed i can change the budget too. Here i have written chaincode in golang.

Answer 1

If requirement is to restrict budget access only for owner, then private data collection can be used. Corresponding APIs are getPrivateData and putPrivateData.