Implement the Valuer/Scanner interface

db.go

@@ -55,7 +55,9 @@ func OpenTestConnection() (db *gorm.DB, err error) {
 		if dbDSN == "" {
 			dbDSN = "user=gorm password=gorm host=localhost dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai"
 		}
-		db, err = gorm.Open(postgres.Open(dbDSN), &gorm.Config{})
+		db, err = gorm.Open(postgres.Open(dbDSN), &gorm.Config{
+			SkipDefaultTransaction: true,
+		})
 	case "sqlserver":
 		// CREATE LOGIN gorm WITH PASSWORD = 'LoremIpsum86';
 		// CREATE DATABASE gorm;
@@ -83,7 +85,7 @@ func OpenTestConnection() (db *gorm.DB, err error) {
 
 func RunMigrations() {
 	var err error
-	allModels := []interface{}{&User{}, &Account{}, &Pet{}, &Company{}, &Toy{}, &Language{}}
+	allModels := []interface{}{&User{}}
 	rand.Seed(time.Now().UnixNano())
 	rand.Shuffle(len(allModels), func(i, j int) { allModels[i], allModels[j] = allModels[j], allModels[i] })
 

gen.go

@@ -14,7 +14,6 @@ func generate() {
 	})
 	g.UseDB(dal.DB)
 
-	g.ApplyBasic(Company{}, Language{}) // Associations
 	g.ApplyBasic(g.GenerateModel("user"), g.GenerateModelAs("account", "AccountInfo"))
 
 	g.Execute()

go.mod

@@ -3,12 +3,13 @@ module gorm.io/playground
 go 1.20
 
 require (
+	github.com/qmuntal/stateless v1.7.0
 	gorm.io/driver/mysql v1.5.2
 	gorm.io/driver/postgres v1.5.2
 	gorm.io/driver/sqlite v1.5.3
 	gorm.io/driver/sqlserver v1.5.1
 	gorm.io/gen v0.3.25
-	gorm.io/gorm v1.25.4
+	gorm.io/gorm v1.25.10
 )
 
 require (
@@ -32,4 +33,4 @@ require (
 	gorm.io/plugin/dbresolver v1.5.0 // indirect
 )
 
-replace gorm.io/gorm => ./gorm
+// replace gorm.io/gorm => ./gorm

main_test.go

@@ -9,12 +9,20 @@ import (
 // TEST_DRIVERS: sqlite, mysql, postgres, sqlserver
 
 func TestGORM(t *testing.T) {
-	user := User{Name: "jinzhu"}
+	user := User{Name: "jinzhu", State: NewCustomType("active")}
 
 	DB.Create(&user)
 
-	var result User
-	if err := DB.First(&result, user.ID).Error; err != nil {
+	var result []User
+	if err := DB.Find(&result).Error; err != nil {
 		t.Errorf("Failed, got error: %v", err)
 	}
+
+	if len(result) == 0 {
+		t.Errorf("Failed, got empty result")
+	}
+
+	if result[0].State.Machine == nil {
+		t.Errorf("Failed, expected: active")
+	}
 }

models.go

@@ -1,60 +1,41 @@
 package main
 
 import (
-	"database/sql"
-	"time"
-
+	"database/sql/driver"
 	"gorm.io/gorm"
+	"log"
 )
 
-// User has one `Account` (has one), many `Pets` (has many) and `Toys` (has many - polymorphic)
-// He works in a Company (belongs to), he has a Manager (belongs to - single-table), and also managed a Team (has many - single-table)
-// He speaks many languages (many to many) and has many friends (many to many - single-table)
-// His pet also has one Toy (has one - polymorphic)
 type User struct {
 	gorm.Model
-	Name      string
-	Age       uint
-	Birthday  *time.Time
-	Account   Account
-	Pets      []*Pet
-	Toys      []Toy `gorm:"polymorphic:Owner"`
-	CompanyID *int
-	Company   Company
-	ManagerID *uint
-	Manager   *User
-	Team      []User     `gorm:"foreignkey:ManagerID"`
-	Languages []Language `gorm:"many2many:UserSpeak"`
-	Friends   []*User    `gorm:"many2many:user_friends"`
-	Active    bool
+	Name  string
+	State CustomType
 }
 
-type Account struct {
-	gorm.Model
-	UserID sql.NullInt64
-	Number string
+type CustomType struct {
+	Machine *Machine
 }
 
-type Pet struct {
-	gorm.Model
-	UserID *uint
-	Name   string
-	Toy    Toy `gorm:"polymorphic:Owner;"`
-}
+type Machine string
 
-type Toy struct {
-	gorm.Model
-	Name      string
-	OwnerID   string
-	OwnerType string
+func NewCustomType(state Machine) CustomType {
+	return CustomType{&state}
 }
 
-type Company struct {
-	ID   int
-	Name string
+// Implement scanner and value interfaces as described in tests https://gorm.io/docs/data_types.html#Scanner-x2F-Valuer
+// https://github.com/go-gorm/gorm/blob/master/tests/scanner_valuer_test.go
+
+func (sm *CustomType) Scan(value interface{}) error {
+	log.Printf("Scanning state %v", value)
+	switch vt := value.(type) {
+	case string:
+		state := vt
+		*sm = NewCustomType(Machine(state))
+	}
+	return nil
 }
 
-type Language struct {
-	Code string `gorm:"primarykey"`
-	Name string
+func (sm CustomType) Value() (driver.Value, error) {
+	log.Printf("Value of state %v", sm)
+	return &sm.Machine, nil
 }