first commit

.gitignore

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+db.sqlite3
+dbtest

Makefile

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+build: db.sqlite3
+	go build dbtest.go
+
+run: db.sqlite3
+	go run dbtest.go
+
+db.sqlite3: migrations/*.sql
+	cat migrations/*.sql | sqlite3 db.sqlite3
+
+all: build db.sqlite3
+
+.PHONY: all build run

dbtest.go

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+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+var db *sql.DB
+
+type Album struct {
+	ID     int64
+	Title  string
+	Artist string
+	Price  float32
+}
+type Test_counter struct {
+	ID      int64
+	Counter int64
+}
+
+func main() {
+	var err error
+	db, err = sql.Open("sqlite3", "./db.sqlite3")
+	if err != nil {
+		log.Fatal(err)
+	}
+	pErr := db.Ping()
+	if pErr != nil {
+		log.Fatal(pErr)
+	}
+	fmt.Println("Connected!")
+
+	count, err := counterIncrement()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("You are visitor #", count)
+
+	albums, err := albumsByArtist("John Coltrane")
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Albums found: %v\n", albums)
+}
+
+func counterIncrement() (int64, error) {
+	_, err := db.Exec("UPDATE `test_counter` SET `counter` = `counter`+1 WHERE `id` = 0")
+	if err != nil {
+		return 0, fmt.Errorf("counterIncrement: %v", err)
+	}
+
+	var count int64
+	row := db.QueryRow("SELECT counter FROM test_counter WHERE id = 0")
+	if err := row.Scan(&count); err != nil {
+		if err == sql.ErrNoRows {
+			return count, fmt.Errorf("counterIncrement: NO COUNTER")
+		}
+		return count, fmt.Errorf("counterIncrement: %v", err)
+	}
+	return count, nil
+}
+
+func albumsByArtist(name string) ([]Album, error) {
+	var albums []Album
+
+	rows, err := db.Query("SELECT * FROM album WHERE artist = ?", name)
+	if err != nil {
+		return nil, fmt.Errorf("albumbsByArtist %q: %v", name, err)
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var alb Album
+		if err := rows.Scan(&alb.ID, &alb.Title, &alb.Artist, &alb.Price); err != nil {
+			return nil, fmt.Errorf("albumbsByArtist %q: %v", name, err)
+		}
+		albums = append(albums, alb)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("albumbsByArtist %q: %v", name, err)
+	}
+	return albums, nil
+}

go.mod

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+module example/data-access
+
+go 1.22.3
+
+require github.com/mattn/go-sqlite3 v1.14.22

go.sum

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+github.com/mattn/go-sqlite3 v1.14.22 h1:2gZY6PC6kBnID23Tichd1K+Z0oS6nE/XwU+Vz/5o4kU=
+github.com/mattn/go-sqlite3 v1.14.22/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=

migrations/0001_add_table_test_counter.sql

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+DROP TABLE IF EXISTS test_counter;
+CREATE TABLE "test_counter" (
+  "id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, 
+  "counter" integer NOT NULL
+);
+
+INSERT INTO test_counter (
+  id,
+  counter
+) VALUES ( 0,0 );

migrations/0002_tutorial_create_tables.sql

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+DROP TABLE IF EXISTS album;
+CREATE TABLE album (
+  "id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, 
+  title      VARCHAR(128) NOT NULL,
+  artist     VARCHAR(255) NOT NULL,
+  price      DECIMAL(5,2) NOT NULL
+);
+

migrations/0003_tutorial_add_data.sql

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+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);