ENS:Quick start with edge clusters

First, add the dependency for the MySQL JDBC driver to the pom.xml file. The following code provides an example:

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.27</version>
</dependency>

Connect to the cluster. Replace the <HOST>, port number, <USER>, <PASSWORD>, <DATABASE>, <YOUR_TABLE_NAME>, and <YOUR_TABLE_COLUMN_NAME> parameters with your actual information.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class DatabaseConnection {
   public DatabaseConnection() {
   }

   public static void main(String[] args) {
      // The endpoint, port, and name of the database to connect to.
      String url = "jdbc:mysql://<HOST>:3306/<DATABASE>?useSSL=false&serverTimezone=UTC";
      // The database account.
      String user = "<USER>";
      // The password of the database account.
      String password = "<PASSWORD>";

      try {
         Class.forName("com.mysql.cj.jdbc.Driver");
         Connection conn = DriverManager.getConnection(url, user, password);
         Statement stmt = conn.createStatement();
         // The name of the data table to retrieve.
         ResultSet rs = stmt.executeQuery("SELECT * FROM `<YOUR_TABLE_NAME>`");

         while(rs.next()) {
            // The name of the column in the data table to retrieve.
            System.out.println(rs.getString("<YOUR_TABLE_COLUMN_NAME>"));
         }

         rs.close();
         stmt.close();
         conn.close();
      } catch (Exception var7) {
         var7.printStackTrace();
      }

   }
}

First, install the PyMySQL library. If you have not installed it, run the following command:

pip3 install PyMySQL

Connect to the cluster. Replace the <HOST>, port number, <USER>, <PASSWORD>, <DATABASE>, and <YOUR_TABLE_NAME> parameters with your actual information.

import pymysql

# Database connection parameters
host = '<HOST>'  # The endpoint of the PolarDB cluster
port = 3306  # The default port is 3306
user = '<USER>'  # The database account
password = '<PASSWORD>'  # The password of the database account
database = '<DATABASE>'  # The name of the database to connect to

try:
    # Create a database connection
    connection = pymysql.connect(
        host=host,
        port=port,
        user=user,
        passwd=password,
        db=database
    )

    # Get the cursor
    with connection.cursor() as cursor:
        # Execute an SQL query
        sql = "SELECT * FROM `<YOUR_TABLE_NAME>`"  # The name of the data table to retrieve
        cursor.execute(sql)

        # Get the query results
        results = cursor.fetchall()
        for row in results:
            print(row)

finally:
    # Close the database connection
    if 'connection' in locals() and connection.open:
        connection.close()

First, install the go-sql-driver/mysql driver. You can run the following command to install it:

go get -u github.com/go-sql-driver/mysql

Connect to the cluster. Replace the <HOST>, port number, <USER>, <PASSWORD>, <DATABASE>, and <YOUR_TABLE_NAME> parameters with your actual information.

package main

import (
    "database/sql"
    "fmt"
    "log"
    _ "github.com/go-sql-driver/mysql"
)

func main() {
    // Database connection parameters
    dbHost := "<HOST>"       // The endpoint of the PolarDB cluster
    dbPort := "3306"         // The default port is 3306
    dbUser := "<USER>"       // The database account
    dbPass := "<PASSWORD>"   // The password of the database account
    dbName := "<DATABASE>"   // The name of the database to connect to

    // Build the Data Source Name (DSN)
    dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local", dbUser, dbPass, dbHost, dbPort, dbName)

    // Open a database connection
    db, err := sql.Open("mysql", dsn)
    if err != nil {
        log.Fatalf("Failed to connect to database: %v", err)
    }
    defer db.Close()

    // Test the connection
    err = db.Ping()
    if err != nil {
        log.Fatalf("Failed to ping database: %v", err)
    }

    // Create a cursor
    var result string
    err = db.QueryRow("SELECT VERSION()").Scan(&result)
    if err != nil {
        log.Fatalf("Failed to execute query: %v", err)
    }

    // Print the database version
    fmt.Printf("Connected to database, version: %s\n", result)

    // Execute an SQL query
    rows, err := db.Query("SELECT * FROM `<YOUR_TABLE_NAME>`") // The name of the data table to retrieve
    if err != nil {
        log.Fatalf("Failed to execute query: %v", err)
    }
    defer rows.Close()
}