PolarDB:Connect to a database

Add the driver dependency to your pom.xml:

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

Connect to the instance. Replace <HOST>, <USER>, <PASSWORD>, and <DATABASE> with your values.

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

public class DatabaseConnection {
    public static void main(String[] args) {
        // Connection string: endpoint, port, and database name
        String url = "jdbc:mysql://<HOST>:3306/<DATABASE>?useSSL=false&serverTimezone=UTC";
        String user = "<USER>";
        String password = "<PASSWORD>";

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

            while (rs.next()) {
                System.out.println(rs.getString("<YOUR_TABLE_COLUMN_NAME>"));
            }

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

Install PyMySQL:

pip3 install PyMySQL

Connect to the instance. Replace <HOST>, <USER>, <PASSWORD>, and <DATABASE> with your values.

import pymysql

host = '<HOST>'         # Database endpoint
port = 3306             # Default port
user = '<USER>'         # Database account
password = '<PASSWORD>' # Account password
database = '<DATABASE>' # Target database

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

    with connection.cursor() as cursor:
        cursor.execute("SELECT * FROM `<YOUR_TABLE_NAME>`")
        results = cursor.fetchall()
        for row in results:
            print(row)

finally:
    if 'connection' in locals() and connection.open:
        connection.close()

Install the driver:

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

Connect to the instance. Replace <HOST>, <USER>, <PASSWORD>, and <DATABASE> with your values.

package main

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

func main() {
    dbHost := "<HOST>"     // Database endpoint
    dbPort := "3306"       // Default port
    dbUser := "<USER>"     // Database account
    dbPass := "<PASSWORD>" // Account password
    dbName := "<DATABASE>" // Target database

    // 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)

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

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

    // Print the database version to confirm a successful connection
    var version string
    if err = db.QueryRow("SELECT VERSION()").Scan(&version); err != nil {
        log.Fatalf("Query failed: %v", err)
    }
    fmt.Printf("Connected. Database version: %s\n", version)

    // Query a table
    rows, err := db.Query("SELECT * FROM `<YOUR_TABLE_NAME>`")
    if err != nil {
        log.Fatalf("Query failed: %v", err)
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        if err := rows.Scan(&id, &name); err != nil {
            log.Fatalf("Scan failed: %v", err)
        }
        fmt.Printf("ID: %d, Name: %s\n", id, name)
    }

    if err = rows.Err(); err != nil {
        log.Fatalf("Row iteration error: %v", err)
    }
}