php小编小新发现,使用GORM的Find(&room)操作时,有时会出现使用空数据填充结构的情况,而不是使用实际数据。这可能导致程序出现错误或异常。为了解决这个问题,我们需要了解GORM的工作原理以及如何正确使用Find操作来填充结构,从而避免这种情况的发生。在本文中,我们将详细介绍这个问题的原因,并提供解决方案来确保正确使用GORM的Find操作。
问题内容
我正在使用 GORM 连接到我的数据库。我正在使用 GoFiber 作为该应用程序。我有两个端点,一个用于列出所有房间的 GET 和一个用于创建房间的 POST。我正在使用 Gorm MySQL 驱动程序并连接到 PlanetScale 托管的数据库。
我的模型:-
type Room struct {
Model
RoomType string `json:"room_type" validate:"required"`
}
我的获取端点代码:-
func GetAllRooms(c *fiber.Ctx) error {
var rooms []entities.Room
res := database.Database.Find(&rooms)
if res.RowsAffected != 0 {
return c.JSON(fiber.Map{"rooms": rooms})
} else {
return c.JSON(fiber.Map{"rooms": nil})
}
}
我的数据库代码:-(托管在planetscale)
var Database *gorm.DB
func ConnectDb() {
dsn := "sample_dsn/mydatabase?tls=true&interpolateParams=true"
db, err := gorm.Open(mysql.Open(dsn))
if err != nil {
panic("Failed to connect to DB")
}
// Setup Migrations Here
db.AutoMigrate(&entities.Booking{})
db.AutoMigrate(&entities.Inventory{})
db.AutoMigrate(&entities.Room{})
db.AutoMigrate(&entities.User{})
Database = db
}
控制台输出:-
{{1 0001-01-01 00:00:00 +0000 UTC 0001-01-01 00:00:00 +0000 UTC {0001-01-01 00:00:00 +0000 UTC false}} }
{{2 0001-01-01 00:00:00 +0000 UTC 0001-01-01 00:00:00 +0000 UTC {0001-01-01 00:00:00 +0000 UTC false}} }
{{3 0001-01-01 00:00:00 +0000 UTC 0001-01-01 00:00:00 +0000 UTC {0001-01-01 00:00:00 +0000 UTC false}} }
{{4 0001-01-01 00:00:00 +0000 UTC 0001-01-01 00:00:00 +0000 UTC {0001-01-01 00:00:00 +0000 UTC false}} }
数据库中的数据:-
id created_at updated_at deleted_at **room_type**
1 2024-01-18 19:27:36.680 2024-01-18 19:27:36.680 DOUBLE_ROOM
2 2024-01-18 19:27:41.206 2024-01-18 19:27:41.206 DOUBLE_ROOM
3 2024-01-18 19:27:49.403 2024-01-18 19:27:49.403 KING_SIZE_AC
4 2024-01-19 11:06:11.789 2024-01-19 11:06:11.789 DOUBLE_BED
API 输出:-
{
"rooms": [
{
"ID": 1,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"room_type": ""
},
{
"ID": 2,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"room_type": ""
},
{
"ID": 3,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"room_type": ""
},
{
"ID": 4,
"CreatedAt": "0001-01-01T00:00:00Z",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"room_type": ""
}
]
}
更新:- 01/20/2024
当我切换到 Postgres 数据库时,这个确切的代码可以工作。所以我改用 Postgres 并关闭此票。
解决方法
我使用以下代码进行了快速测试:
package main
import (
"github.com/gofiber/fiber/v2"
"gorm.io/driver/postgres"
"gorm.io/gorm"
"log"
)
var (
dsn = "host=localhost user=postgres password=secret dbname=mySampleDb port=5432 sslmode=disable"
)
type Room struct {
gorm.Model
RoomType string `json:"room_type" validate:"required"`
}
var DB *gorm.DB
func main() {
initDb()
app := fiber.New()
app.Get("/", getAllRoomsForFiber)
app.Listen(":3000")
}
func getAllRoomsForFiber(c *fiber.Ctx) error {
var rooms []Room
res := DB.Find(&rooms)
if res.RowsAffected != 0 {
return c.JSON(fiber.Map{"rooms": rooms})
} else {
return c.JSON(fiber.Map{"rooms": nil})
}
}
func seedDb() {
DB.Create(&Room{RoomType: "single"})
DB.Create(&Room{RoomType: "Deluxe bed"})
DB.Create(&Room{RoomType: "Twin bed"})
DB.Create(&Room{RoomType: "King Size bed"})
}
func initDb() {
db, err := gorm.Open(postgres.Open(dsn))
if err != nil {
log.Fatal("couldn't connect to db")
}
DB = db
db.AutoMigrate(&Room{})
seedDb()
}
这就是我得到的:
德巴4139f5302207be648f12c74de60e