| 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "database/sql" |
| 5 | "errors" |
| 6 | "strings" |
| 7 | ) |
| 8 | |
| 9 | type Category struct { |
| 10 | ID int64 |
| 11 | Name string |
| 12 | CreatedAt string |
| 13 | } |
| 14 | |
| 15 | func listCategories(db *sql.DB) ([]Category, error) { |
| 16 | rows, err := db.Query(`SELECT id, name, created_at FROM categories ORDER BY name ASC`) |
| 17 | if err != nil { |
| 18 | return nil, err |
| 19 | } |
| 20 | defer rows.Close() |
| 21 | var out []Category |
| 22 | for rows.Next() { |
| 23 | var c Category |
| 24 | if err := rows.Scan(&c.ID, &c.Name, &c.CreatedAt); err != nil { |
| 25 | return nil, err |
| 26 | } |
| 27 | out = append(out, c) |
| 28 | } |
| 29 | return out, rows.Err() |
| 30 | } |
| 31 | |
| 32 | func getOrCreateCategory(db *sql.DB, name string) (*Category, error) { |
| 33 | name = strings.TrimSpace(name) |
| 34 | if name == "" { |
| 35 | return nil, nil |
| 36 | } |
| 37 | var c Category |
| 38 | err := db.QueryRow(`SELECT id, name, created_at FROM categories WHERE name = ?`, name).Scan(&c.ID, &c.Name, &c.CreatedAt) |
| 39 | if err == nil { |
| 40 | return &c, nil |
| 41 | } |
| 42 | if !errors.Is(err, sql.ErrNoRows) { |
| 43 | return nil, err |
| 44 | } |
| 45 | res, err := db.Exec(`INSERT INTO categories (name) VALUES (?)`, name) |
| 46 | if err != nil { |
| 47 | var existing Category |
| 48 | if err2 := db.QueryRow(`SELECT id, name, created_at FROM categories WHERE name = ?`, name).Scan(&existing.ID, &existing.Name, &existing.CreatedAt); err2 == nil { |
| 49 | return &existing, nil |
| 50 | } |
| 51 | return nil, err |
| 52 | } |
| 53 | id, _ := res.LastInsertId() |
| 54 | return getCategory(db, id) |
| 55 | } |
| 56 | |
| 57 | func getCategory(db *sql.DB, id int64) (*Category, error) { |
| 58 | var c Category |
| 59 | err := db.QueryRow(`SELECT id, name, created_at FROM categories WHERE id = ?`, id).Scan(&c.ID, &c.Name, &c.CreatedAt) |
| 60 | if errors.Is(err, sql.ErrNoRows) { |
| 61 | return nil, nil |
| 62 | } |
| 63 | if err != nil { |
| 64 | return nil, err |
| 65 | } |
| 66 | return &c, nil |
| 67 | } |
| 68 | |
| 69 | func deleteCategory(db *sql.DB, id int64) (bool, error) { |
| 70 | res, err := db.Exec(`DELETE FROM categories WHERE id = ?`, id) |
| 71 | if err != nil { |
| 72 | return false, err |
| 73 | } |
| 74 | n, _ := res.RowsAffected() |
| 75 | return n > 0, nil |
| 76 | } |