tutorial: terjemahkan "Tutorial: Accessing a relational database"

Tutorial asli ada di https://go.dev/doc/tutorial/database-access .

4 files changed, 147 insertions, 0 deletions

diff --git a/_content/doc/tutorial/database-access/data-access/create-tables.sql b/_content/doc/tutorial/database-access/data-access/create-tables.sql
new file mode 100644
index 0000000..63290a0
--- /dev/null
+++ b/_content/doc/tutorial/database-access/data-access/create-tables.sql
@@ -0,0 +1,16 @@
+DROP TABLE IF EXISTS album;
+CREATE TABLE album (
+  id         SERIAL,
+  title      VARCHAR(128) NOT NULL,
+  artist     VARCHAR(255) NOT NULL,
+  price      DECIMAL(5,2) NOT NULL,
+  PRIMARY KEY (id)
+);
+
+INSERT INTO album
+  (title, artist, price)
+VALUES
+  ('Blue Train', 'John Coltrane', 56.99),
+  ('Giant Steps', 'John Coltrane', 63.99),
+  ('Jeru', 'Gerry Mulligan', 17.99),
+  ('Sarah Vaughan', 'Sarah Vaughan', 34.98);
diff --git a/_content/doc/tutorial/database-access/data-access/go.mod b/_content/doc/tutorial/database-access/data-access/go.mod
new file mode 100644
index 0000000..e33ed8d
--- /dev/null
+++ b/_content/doc/tutorial/database-access/data-access/go.mod
@@ -0,0 +1,5 @@
+module github.com/golang-id/web/data-access
+
+go 1.24.0
+
+require github.com/lib/pq v1.10.9
diff --git a/_content/doc/tutorial/database-access/data-access/go.sum b/_content/doc/tutorial/database-access/data-access/go.sum
new file mode 100644
index 0000000..aeddeae
--- /dev/null
+++ b/_content/doc/tutorial/database-access/data-access/go.sum
@@ -0,0 +1,2 @@
+github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
diff --git a/_content/doc/tutorial/database-access/data-access/main.go b/_content/doc/tutorial/database-access/data-access/main.go
new file mode 100644
index 0000000..588422c
--- /dev/null
+++ b/_content/doc/tutorial/database-access/data-access/main.go
@@ -0,0 +1,124 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/lib/pq"
+)
+
+type Album struct {
+	ID     int64
+	Title  string
+	Artist string
+	Price  float32
+}
+
+// albumsByArtist mengambil album-album berdasarkan nama artis.
+func albumsByArtist(db *sql.DB, name string) ([]Album, error) {
+	// albums adalah slice yang menyimpan data dari hasil kueri.
+	var albums []Album
+
+	rows, err := db.Query(`
+		SELECT id, title, artist, price
+		FROM album
+		WHERE artist = $1`, name)
+	if err != nil {
+		return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+	}
+	defer rows.Close()
+
+	// Iterasi pada rows, menggunakan Scan untuk menyimpan data ke dalam
+	// struct Album.
+	for rows.Next() {
+		var alb Album
+		err := rows.Scan(&alb.ID, &alb.Title, &alb.Artist, &alb.Price)
+		if err != nil {
+			return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+		}
+		albums = append(albums, alb)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+	}
+	return albums, nil
+}
+
+// albumByID kueri album berdasarkan ID.
+func albumByID(db *sql.DB, id int64) (Album, error) {
+	// Variabel yang menyimpan baris kembalian dari basis-data.
+	var alb Album
+
+	row := db.QueryRow(`
+		SELECT id, title, artist, price
+		FROM album WHERE id = $1", id)
+	err := row.Scan(&alb.ID, &alb.Title, &alb.Artist, &alb.Price)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return alb, fmt.Errorf("albumsById %d: album tidak ditemukan", id)
+		}
+		return alb, fmt.Errorf("albumsById %d: %v", id, err)
+	}
+	return alb, nil
+}
+
+// addAlbum menambahkan sebuah album baru ke dalam basis-data dan
+// mengembalikan ID album yang baru.
+func addAlbum(db *sql.DB, alb Album) (int64, error) {
+	var id int64
+	err := db.QueryRow(`
+		INSERT INTO album (title, artist, price)
+		VALUES ($1, $2, $3)
+		RETURNING id`,
+		alb.Title, alb.Artist, alb.Price).Scan(&id)
+	if err != nil {
+		return 0, fmt.Errorf("addAlbum: %v", err)
+	}
+	return id, nil
+}
+
+func main() {
+	// Contoh DATABASE_URL = "postgres://username:password@localhost:5432/database_name"
+	databaseUrl := os.Getenv("DATABASE_URL")
+	var connector *pq.Connector
+	var err error
+	connector, err = pq.NewConnector(databaseUrl)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var db *sql.DB
+	db = sql.OpenDB(connector)
+	defer db.Close()
+
+	err = db.Ping()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("Terhubung!")
+
+	albums, err := albumsByArtist(db, "John Coltrane")
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Albums ditemukan: %v\n", albums)
+
+	// Tulis langsung ID 2 untuk menguji kueri.
+	alb, err := albumByID(db, 2)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Album ditemukan: %v\n", alb)
+
+	albID, err := addAlbum(db, Album{
+		Title:  "The Modern Sound of Betty Carter",
+		Artist: "Betty Carter",
+		Price:  49.99,
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("ID dari album baru: %v\n", albID)
+}