Use tag to set primary key

README.md

@@ -891,7 +891,7 @@ If you have an existing database schema, and the primary key field is different
 
 ```go
 type Animal struct {
-    AnimalId     int64 `primaryKey:"yes"`
+    AnimalId     int64 `gorm:"primary_key:yes"`
     Birthday     time.Time
     Age          int64
 }

create_test.go

@@ -56,6 +56,17 @@ func TestCreate(t *testing.T) {
 	}
 }
 
+func TestCreateWithNoStdPrimaryKey(t *testing.T) {
+	animal := Animal{Name: "Ferdinand"}
+	if db.Save(&animal).Error != nil {
+		t.Errorf("No error should happen when create an record without std primary key")
+	}
+
+	if animal.Counter == 0 {
+		t.Errorf("No std primary key should be filled value after create")
+	}
+}
+
 func TestAnonymousScanner(t *testing.T) {
 	user := User{Name: "anonymous_scanner", Role: Role{Name: "admin"}}
 	db.Save(&user)

main_private.go

@@ -45,7 +45,7 @@ func (s *DB) print(v ...interface{}) {
 }
 
 func (s *DB) log(v ...interface{}) {
-	if s.logMode == 2 {
+	if s != nil && s.logMode == 2 {
 		s.print(append([]interface{}{"log", fileWithLineNum()}, v...)...)
 	}
 }

scope.go

@@ -253,7 +253,10 @@ func (scope *Scope) Fields() []*Field {
 		field.IsBlank = isBlank(value)
 
 		// Search for primary key tag identifier
-		field.isPrimaryKey = scope.PrimaryKey() == field.DBName || fieldStruct.Tag.Get("primaryKey") != ""
+		settings := parseTagSetting(fieldStruct.Tag.Get("gorm"))
+		if _, ok := settings["PRIMARY_KEY"]; scope.PrimaryKey() == field.DBName || ok {
+			field.isPrimaryKey = true
+		}
 
 		if field.isPrimaryKey {
 			scope.primaryKey = field.DBName

structs_test.go

@@ -119,7 +119,7 @@ func (i *Num) Scan(src interface{}) error {
 }
 
 type Animal struct {
-	Counter   int64 `primaryKey:"yes"`
+	Counter   int64 `gorm:"primary_key:yes"`
 	Name      string
 	From      string //test reserved sql keyword as field name
 	CreatedAt time.Time

utils.go

@@ -106,7 +106,8 @@ func GetPrimaryKey(value interface{}) string {
 				continue
 			}
 
-			if fieldStruct.Tag.Get("primaryKey") != "" {
+			settings := parseTagSetting(fieldStruct.Tag.Get("gorm"))
+			if _, ok := settings["PRIMARY_KEY"]; ok {
 				return fieldStruct.Name
 			}
 		}