Example showing the issue we're facing with null.String

db.go

@@ -11,6 +11,7 @@ import (
 	"gorm.io/driver/postgres"
 	"gorm.io/driver/sqlite"
 	"gorm.io/driver/sqlserver"
+
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
 )

go.mod

@@ -1,35 +1,45 @@
 module gorm.io/playground
 
-go 1.20
+go 1.22.0
+
+toolchain go1.23.2
 
 require (
-	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/driver/mysql v1.5.7
+	gorm.io/driver/postgres v1.5.9
+	gorm.io/driver/sqlite v1.5.6
+	gorm.io/driver/sqlserver v1.5.3
+	gorm.io/gen v0.3.26
+	gorm.io/gen/examples v0.0.0-00010101000000-000000000000
+	gorm.io/gorm v1.25.12
 )
 
 require (
-	github.com/go-sql-driver/mysql v1.7.1 // indirect
+	filippo.io/edwards25519 v1.1.0 // indirect
+	github.com/go-sql-driver/mysql v1.8.1 // indirect
 	github.com/golang-sql/civil v0.0.0-20220223132316-b832511892a9 // indirect
 	github.com/golang-sql/sqlexp v0.1.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
-	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
-	github.com/jackc/pgx/v5 v5.4.3 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.7.1 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
-	github.com/mattn/go-sqlite3 v1.14.17 // indirect
-	github.com/microsoft/go-mssqldb v1.5.0 // indirect
-	golang.org/x/crypto v0.14.0 // indirect
-	golang.org/x/mod v0.14.0 // indirect
-	golang.org/x/sys v0.14.0 // indirect
-	golang.org/x/text v0.13.0 // indirect
-	golang.org/x/tools v0.15.0 // indirect
-	gorm.io/datatypes v1.1.1-0.20230130040222-c43177d3cf8c // indirect
-	gorm.io/hints v1.1.0 // indirect
-	gorm.io/plugin/dbresolver v1.5.0 // indirect
+	github.com/mattn/go-sqlite3 v1.14.24 // indirect
+	github.com/microsoft/go-mssqldb v1.7.2 // indirect
+	golang.org/x/crypto v0.28.0 // indirect
+	golang.org/x/mod v0.21.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
+	golang.org/x/text v0.19.0 // indirect
+	golang.org/x/tools v0.26.0 // indirect
+	gopkg.in/guregu/null.v3 v3.5.0 // indirect
+	gorm.io/datatypes v1.2.2 // indirect
+	gorm.io/hints v1.1.2 // indirect
+	gorm.io/plugin/dbresolver v1.5.3 // indirect
 )
 
 replace gorm.io/gorm => ./gorm
+
+replace gorm.io/gen/examples => ../gen/examples

main_test.go

@@ -2,19 +2,49 @@ package main
 
 import (
 	"testing"
+
+	"gopkg.in/guregu/null.v3"
 )
 
 // GORM_REPO: https://github.com/go-gorm/gorm.git
 // GORM_BRANCH: master
 // TEST_DRIVERS: sqlite, mysql, postgres, sqlserver
 
 func TestGORM(t *testing.T) {
-	user := User{Name: "jinzhu"}
+
+	user := User{Name: "jinzhu", OptionalID: null.StringFrom("this_is_an_optional_id")}
 
 	DB.Create(&user)
 
 	var result User
 	if err := DB.First(&result, user.ID).Error; err != nil {
 		t.Errorf("Failed, got error: %v", err)
 	}
+
+	// Update the user's name and optionalID (to be NULL)
+	toUpdate := user
+	toUpdate.OptionalID = null.String{}
+	toUpdate.Name = "Steve"
+
+	err := DB.Save(&toUpdate).Error
+	if err != nil {
+		t.Errorf("Failed, got error: %v", err)
+	}
+
+	// Refetch the updated user into &user
+	if err := DB.Model(user).
+		First(&user).
+		Error; err != nil {
+		t.Errorf("Failed, got error: %v", err)
+	}
+
+	// Name is updated
+	if user.Name != "Steve" {
+		t.Errorf("Updated name was not fetched")
+	}
+
+	// OptionalID isn't updated (should be invalid)
+	if user.OptionalID.Valid {
+		t.Errorf("Updated optional ID was not fetched")
+	}
 }

models.go

@@ -4,6 +4,8 @@ import (
 	"database/sql"
 	"time"
 
+	"gopkg.in/guregu/null.v3"
+
 	"gorm.io/gorm"
 )
 
@@ -13,20 +15,21 @@ import (
 // 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
+	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
+	OptionalID null.String
 }
 
 type Account struct {