learning_go/go-code-samples/database-sql-package-goproject/prepared/prepared.go
2025-12-20 10:21:45 +03:00

74 lines
1.4 KiB
Go

package main
import (
"database/sql"
"fmt"
"log"
"os"
"github.com/go-sql-driver/mysql"
)
var db *sql.DB
type Album struct {
ID int64
Title string
Artist string
Price float32
Quantity int64
}
func main() {
// Capture connection properties.
cfg := mysql.Config{
User: os.Getenv("DBUSER"),
Passwd: os.Getenv("DBPASS"),
Net: "tcp",
Addr: "127.0.0.1:3306",
DBName: "recordings",
}
// Get a database handle.
var err error
db, err = sql.Open("mysql", cfg.FormatDSN())
if err != nil {
log.Fatal(err)
}
pingErr := db.Ping()
if pingErr != nil {
log.Fatal(pingErr)
}
fmt.Println("Connected!")
// Hard-code ID 2 here to test the query.
Album, err := albumByID(2)
if err != nil {
log.Fatal(err)
}
fmt.Printf("Album found: %v\n", Album)
}
// AlbumByID retrieves the specified album.
func albumByID(id int) (Album, error) {
// Define a prepared statement. You'd typically define the statement
// elsewhere and save it for use in functions such as this one.
stmt, err := db.Prepare("SELECT * FROM album WHERE id = ?")
if err != nil {
log.Fatal(err)
}
var album Album
// Execute the prepared statement, passing in an id value for the
// parameter whose placeholder is ?
err = stmt.QueryRow(id).Scan(&album.ID, &album.Title, &album.Artist, &album.Price, &album.Quantity)
if err != nil {
if err == sql.ErrNoRows {
// Handle the case of no rows returned.
}
return album, err
}
return album, nil
}