Private Oracle for Off-Chain Data Snapshot

Overview

Our private Oracle utilizes the C++ programming language to interface with SQL databases and Ethereum-based smart contracts. This document offers an overview of the process and includes some basic code examples.

Connecting to a SQL Database

C++ enables database connectivity through various libraries such as ODBC, MySQL Connector/C++, etc. Let's take an example of connecting to a MySQL database.

Connecting to a SQL Database

C++ enables database connectivity through various libraries such as ODBC, MySQL Connector/C++ etc. Let's take an example of connecting to a MySQL database.

#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>

using namespace std;

int main() {
    sql::mysql::MySQL_Driver *driver;
    sql::Connection *con;

    driver = sql::mysql::get_mysql_driver_instance();
    con = driver->connect("tcp://127.0.0.1:3306", "user", "password");

    delete con;
    return 0;
}

Extracting Data From SQL Database

Once connected, we can extract data using SQL queries. The ResultSet object stores the data returned by the queries.

sql::Statement *stmt;
sql::ResultSet  *res;

stmt = con->createStatement();
res = stmt->executeQuery("SELECT 'property_address', 'property_value' FROM 'property_table'");

while (res->next()) {
  cout << "Address: " << res->getString("property_address");
  cout << "Value: " << res->getString("property_value");
}

delete res;
delete stmt;

Pushing Data To Ethereum Blockchain

To interface with the Ethereum blockchain, we'll use the web3.cpp library. We first establish a connection to an Ethereum node and then call a function in our smart contract to update the data.

#include <web3cpp/web3cpp.h>

int main() {
    web3cpp::web3 web3("http://localhost:8545"); // Connect to Ethereum node
    web3cpp::Contract contract = web3.Contract("0x123...abc"); // Replace with your contract address

    string property_address = "123 Main St"; // Replace with fetched data
    string property_value = "500000"; // Replace with fetched data

    contract.call("updateProperty", property_address, property_value); // Replace 'updateProperty' with your contract function

    return 0;
}

The 'updateProperty' function should exist in your smart contract and have the logic to update the state of the contract.

This example provides a basic approach to fetching data from an SQL database and pushing that data onto the Ethereum blockchain. It's crucial to consider factors such as security, error handling, scalability, and regulatory compliance while developing a production-grade oracle. It's also essential to use a private key management solution to sign transactions securely.

Conclusion

We believe this documentation gives an insightful look into how our Private Oracle interfaces with off-chain data sources, and Ethereum smart contracts. For further details or discussions, please reach out to us.