Storing Customer Data on Ethereum: Deploying a Smart Contract (Part 2)

Introduction

This guide demonstrates how to use Ethereum's Smart Contracts for decentralized data storage, specifically focusing on customer data management. While Smart Contracts aren't AI-powered, they function as self-executing programs on the Ethereum blockchain, written in Solidity.

Key Objectives

Develop a Smart Contract for storing structured customer data
Deploy the contract to the Ethereum network
Prepare essential components for future interactions (e.g., via C#)

Tools & Prerequisites

Development Tools

Visual Studio Code (Primary IDE)
Node.js (JavaScript runtime)
Truffle Suite (Ethereum development framework)
```
npm install -g truffle
```

Environment Setup

1. Initialize Project

mkdir customers
cd customers
truffle init

This generates the foundational structure for Solidity development.

Smart Contract Development

1. Create `DataStorage.sol`

Under the contracts folder, create this file with the following structure:

pragma solidity ^0.8.0;

contract DataStorage {
    struct Company {
        string id;
        string name;
        string tel;
        string addr;
    }
    
    mapping(string => Company) public companyHashMap;
    
    function addCompanyData(
        string memory id,
        string memory name,
        string memory tel,
        string memory addr
    ) public {
        companyHashMap[id] = Company(id, name, tel, addr);
    }
}

2. Configure Deployment

Edit migrations/2_deploy_contracts.js:

const DataStorage = artifacts.require("DataStorage");
module.exports = function(deployer) {
  deployer.deploy(DataStorage);
};

3. Network Settings

Update truffle.js with your Ethereum RPC endpoint and network ID:

module.exports = {
  networks: {
    azureNetwork: {
      host: "YOUR_RPC_ENDPOINT",
      port: 8545,
      network_id: "*"
    }
  }
};

Deployment Process

1. Unlock Ethereum Account

Access your Azure-hosted Ethereum node via SSH and run:

geth attach
personal.unlockAccount(personal.listAccounts[0], "YOUR_PASSWORD", 0)

2. Deploy Contract

truffle migrate --reset --network azureNetwork

3. Verify Deployment

Enter the Truffle console:

truffle console --network azureNetwork

Then fetch contract details:

DataStorage.deployed().then(instance => tp=instance)

👉 Learn more about Smart Contract addresses

Critical Information

Contract Address: Found in deployment logs (e.g., 0x123...abc).
Account Address: Retrieve via:
```
personal.listAccounts[0]
```

Function Signature Hash:

web3.sha3("addCompanyData(string,string,string,string)").substring(0, 10)

Example output: 0x4d586d83.

FAQs

Q1: Why use Smart Contracts for data storage?

A1: They provide immutability, transparency, and decentralization—ideal for audit trails and trustless systems.

Q2: How do I interact with the deployed contract?

A2: Use libraries like web3.js or ethers.js, or call via JSON-RPC (covered in Part 3).

Q3: Is Solidity the only language for Smart Contracts?

A3: While Solidity is dominant, alternatives like Vyper exist.

Next Steps

In Part 3, we'll explore interacting with the contract using C# and JSON-RPC. 👉 Advanced Ethereum integrations

Always test contracts on a testnet before mainnet deployment!