Save before associations

callbacks/create.go

@@ -42,6 +42,29 @@ func BeforeCreate(db *gorm.DB) {
 }
 
 func SaveBeforeAssociations(db *gorm.DB) {
+	if db.Statement.Schema != nil {
+		for _, rel := range db.Statement.Schema.Relationships.BelongsTo {
+			switch db.Statement.ReflectValue.Kind() {
+			case reflect.Slice:
+			case reflect.Struct:
+				if _, zero := rel.Field.ValueOf(db.Statement.ReflectValue); !zero {
+					f := rel.Field.ReflectValueOf(db.Statement.ReflectValue)
+					if f.Kind() == reflect.Ptr {
+						db.Session(&gorm.Session{}).Create(f.Interface())
+					} else {
+						db.Session(&gorm.Session{}).Create(f.Addr().Interface())
+					}
+
+					for _, ref := range rel.References {
+						if !ref.OwnPrimaryKey {
+							fv, _ := ref.PrimaryKey.ValueOf(f)
+							ref.ForeignKey.Set(db.Statement.ReflectValue, fv)
+						}
+					}
+				}
+			}
+		}
+	}
 }
 
 func Create(config *Config) func(db *gorm.DB) {

logger/sql.go

@@ -51,20 +51,22 @@ func ExplainSQL(sql string, numericPlaceholder *regexp.Regexp, escaper string, v
 			if v == nil {
 				vars[idx] = "NULL"
 			} else {
-				rv := reflect.Indirect(reflect.ValueOf(v))
+				rv := reflect.ValueOf(v)
+
 				if !rv.IsValid() {
 					vars[idx] = "NULL"
-					return
-				}
-
-				for _, t := range convertableTypes {
-					if rv.Type().ConvertibleTo(t) {
-						convertParams(rv.Convert(t).Interface(), idx)
-						return
+				} else if rv.Kind() == reflect.Ptr && !rv.IsZero() {
+					convertParams(reflect.Indirect(rv).Interface(), idx)
+				} else {
+					for _, t := range convertableTypes {
+						if rv.Type().ConvertibleTo(t) {
+							convertParams(rv.Convert(t).Interface(), idx)
+							return
+						}
 					}
-				}
 
-				vars[idx] = escaper + strings.Replace(fmt.Sprint(v), escaper, "\\"+escaper, -1) + escaper
+					vars[idx] = escaper + strings.Replace(fmt.Sprint(v), escaper, "\\"+escaper, -1) + escaper
+				}
 			}
 		}
 	}

tests/create.go

@@ -40,4 +40,45 @@ func TestCreate(t *testing.T, db *gorm.DB) {
 			AssertObjEqual(t, newUser, user, "Name", "Age", "Birthday")
 		}
 	})
+
+	TestCreateAssociations(t, db)
+}
+
+func TestCreateAssociations(t *testing.T, db *gorm.DB) {
+	db.Migrator().DropTable(&Company{})
+	db.Migrator().AutoMigrate(&Company{})
+
+	t.Run("Create-BelongsToAssociation", func(t *testing.T) {
+		var user = User{
+			Name:     "create",
+			Age:      18,
+			Birthday: Now(),
+			Company:  Company{Name: "company-belongs-to-association"},
+			Manager:  &User{Name: "manager-belongs-to-association"},
+		}
+
+		if err := db.Create(&user).Error; err != nil {
+			t.Fatalf("errors happened when create: %v", err)
+		}
+
+		if user.CompanyID == nil {
+			t.Errorf("Failed to create belongs to association - Company")
+		} else {
+			var company Company
+			db.First(&company, "id = ?", *user.CompanyID)
+			if company.Name != "company-belongs-to-association" {
+				t.Errorf("Failed to query saved belongs to association - Company")
+			}
+		}
+
+		if user.ManagerID == nil {
+			t.Errorf("Failed to create belongs to association - Manager")
+		} else {
+			var manager User
+			db.First(&manager, "id = ?", *user.ManagerID)
+			if manager.Name != "manager-belongs-to-association" {
+				t.Errorf("Failed to query saved belongs to association - Manager")
+			}
+		}
+	})
 }