Databases

One of the most asked questions I get about web development in Go is how toconnect to a SQL database. Thankfully, Go has a fantastic SQL package in thestandard library that allows us to use a whole slew of drivers for differentSQL databases. In this example we will connect to a SQLite database, but thesyntax (minus some small SQL semantics) is the same for a MySQL or PostgreSQLdatabase.

  1. package main
  3. import (
  4.     "database/sql"
  5.     "fmt"
  6.     "log"
  7.     "net/http"
  9.     _ "github.com/mattn/go-sqlite3"
  10. )
  12. func main() {
  13.     db := NewDB()
  14.     log.Println("Listening on :8080")
  15.     http.ListenAndServe(":8080", ShowBooks(db))
  16. }
  18. func ShowBooks(db *sql.DB) http.Handler {
  19.     return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
  20.         var title, author string
  21.         err := db.QueryRow("select title, author from books").Scan(&title, &author)
  22.         if err != nil {
  23.             panic(err)
  24.         }
  26.         fmt.Fprintf(rw, "The first book is '%s' by '%s'", title, author)
  27.     })
  28. }
  30. func NewDB() *sql.DB {
  31.     db, err := sql.Open("sqlite3", "example.sqlite")
  32.     if err != nil {
  33.         panic(err)
  34.     }
  36.     _, err = db.Exec("create table if not exists books(title text, author text)")
  37.     if err != nil {
  38.         panic(err)
  39.     }
  41.     return db
  42. }

Exercises

  • Make use of the Query function on our sql.DB instance to extract a collection of rows and map them to structs.
  • Add the ability to insert new records into our database by using an HTML form.
  • go get github.com/jmoiron/sqlx and observe the improvements made over the existing database/sql package in the standard library.

原文: https://codegangsta.gitbooks.io/building-web-apps-with-go/content/databases/index.html