React Native and Mysql Connection

There is no direct connection between RN and Mysql. Use Node js for this.

Step: 1

npm install express

npm install body-parser

npm install mysql

Step: 2

const connection = mysql.createPool({
  host     : 'localhost', // Your connection adress (localhost).
  user     : 'root',     // Your database's username.
  password : '',        // Your database's password.
  database : 'my_db'   // Your database's name.
});

// Starting our app.
const app = express();

// Creating a GET route that returns data from the 'users' table.
app.get('/users', function (req, res) {
    // Connecting to the database.
    connection.getConnection(function (err, connection) {

    // Executing the MySQL query (select all data from the 'users' table).
    connection.query('SELECT * FROM users', function (error, results, fields) {
      // If some error occurs, we throw an error.
      if (error) throw error;

      // Getting the 'response' from the database and sending it to our route. This is were the data is.
      res.send(results)
    });
  });
});

// Starting our server.
app.listen(3000, () => {
 console.log('Go to http://localhost:3000/users so you can see the data.');
});

Now, how do we get that data on our React Native App?

That's simple, we use the fetch function. To do that, instead of using 'localhost:3000', you'll have to directly insert your PC's ip adress. If you use 'localhost', you're acessing your smartphone/emulator's localhost. And that's not what we want. Follow this example:

test(){
    fetch('http://yourPCip:3000/users')
      .then(response => response.json())
      .then(users => console.warn(users))
  }