Blockchain By Example

The CRUD data repository

As our main data repository, we will use a mapping structure to index all enrolled players using their address. If you remember, in the previous chapter, Peer-to-Peer Auctions in Ethereum we learned that a mapping is similar to a big key-value database with all possible key values filled with zeros.

In the tontine.sol file, add the following code:

pragma solidity ^0.4.24;contract Cplayer{    struct player{        string name;        uint PhoneNumber;        address Paddress;        uint id;    }    mapping(address => player) players;}

The code is pretty self-explanatory: we declare a new type called player, which is a structure (struct) that represents a user’s details.

We also declare a players mapping to store the users' details. In the mapping definition ...