PolarDB:Menghubungkan ke database

Tambahkan dependensi driver JDBC PostgreSQL ke file pom.xml Anda. Contoh kode:

<dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
  <version>42.2.18</version>
</dependency>

Hubungkan ke kluster. Ganti placeholder <HOST>, <PORT>, <USER>, <PASSWORD>, <DATABASE>, <YOUR_TABLE_NAME>, dan <YOUR_TABLE_COLUMN_NAME> dengan parameter koneksi kluster yang sebenarnya.

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

public class PolarDBConnection {
    public static void main(String[] args) {
        // URL, username, dan password database.
        String url = "jdbc:postgresql://<HOST>:<PORT>/<DATABASE>";
        String user = "<USER>";
        String password = "<PASSWORD>";

        try {
            // Muat driver JDBC PostgreSQL.
            Class.forName("org.postgresql.Driver");
            
            // Bangun koneksi.
            Connection conn = DriverManager.getConnection(url, user, password);
            
            // Buat objek Statement.
            Statement stmt = conn.createStatement();
            
            // Eksekusi kueri SQL.
            ResultSet rs = stmt.executeQuery("SELECT * FROM <YOUR_TABLE_NAME>");
            
            // Proses set hasil.
            while (rs.next()) {
                System.out.println(rs.getString("<YOUR_TABLE_COLUMN_NAME>"));
            }
            
            // Tutup sumber daya.
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Instal library psycopg2.

pip3 install psycopg2-binary

Hubungkan ke kluster. Ganti placeholder <HOST>, <PORT>, <USER>, <PASSWORD>, <DATABASE>, dan <YOUR_TABLE_NAME> dengan parameter koneksi kluster yang sebenarnya.

import psycopg2

try:
    # Parameter koneksi
    conn = psycopg2.connect(
        host="<HOST>",  # Titik akhir kluster.
        database="<DATABASE>",  # Nama database.
        user="<USER>",  # Username.
        password="<PASSWORD>",  # Password.
        port="<PORT>"  # Nomor port.
    )

    # Buat objek cursor.
    cursor = conn.cursor()

    # Eksekusi kueri.
    cursor.execute("SELECT * FROM <YOUR_TABLE_NAME>")

    # Dapatkan semua hasil.
    records = cursor.fetchall()
    for record in records:
        print(record)
        
except Exception as e:
    print("Error:", e)
finally:
    # Tutup koneksi.
    if 'cursor' in locals():
        cursor.close()
    if 'conn' in locals():
        conn.close()

Instal driver lib/pq.

go get -u github.com/lib/pq

Hubungkan ke kluster. Ganti placeholder <HOST>, <PORT>, <USER>, <PASSWORD>, <DATABASE>, dan <YOUR_TABLE_NAME> dengan parameter koneksi kluster yang sebenarnya.

package main

import (
    "database/sql"
    "fmt"
    "log"

    _ "github.com/lib/pq" // Inisialisasi driver PostgreSQL.
)

func main() {
    // Format string koneksi.
    connStr := "user=<USER> password=<PASSWORD> dbname=<DATABASE> host=<HOST> port=<PORT> sslmode=disable"

    // Buka koneksi database.
    db, err := sql.Open("postgres", connStr)
    if err != nil {
        log.Fatal(err)
    }
    defer db.Close() // Tutup koneksi saat program keluar.

    // Uji koneksi.
    err = db.Ping()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Connected to PostgreSQL!")

    // Eksekusi kueri.
    rows, err := db.Query("SELECT * FROM <YOUR_TABLE_NAME>")
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()
}