Handle SubStruct

do.go

@@ -566,8 +566,10 @@ func (s *Do) combinedSql() string {
 func (s *Do) createTable() *Do {
 	var sqls []string
 	for _, field := range s.model.fields("") {
+		if len(field.SqlType) > 0 {
 			sqls = append(sqls, field.DbName+" "+field.SqlType)
 		}
+	}
 
 	s.sql = fmt.Sprintf(
 		"CREATE TABLE \"%v\" (%v)",

gorm_test.go

@@ -995,3 +995,39 @@ func TestNot(t *testing.T) {
 		t.Errorf("Should find all users's name not equal 3")
 	}
 }
+
+type Category struct {
+	Id   int64
+	Name string
+}
+
+type Post struct {
+	Id       int64
+	Title    string
+	Body     string
+	Comments []Comment
+	Category Category
+}
+
+type Comment struct {
+	Id      int64
+	Content string
+	Post    Post
+}
+
+func TestSubStruct(t *testing.T) {
+	db.CreateTable(Category{})
+	db.CreateTable(Post{})
+	db.CreateTable(Comment{})
+
+	post := Post{
+		Title:    "post 1",
+		Body:     "body 1",
+		Comments: []Comment{{Content: "Comment 1"}, {Content: "Comment 2"}},
+		Category: Category{Name: "category"},
+	}
+
+	if err := db.Save(&post).Error; err != nil {
+		t.Errorf("Got errors when save post", err)
+	}
+}

model.go

@@ -77,6 +77,7 @@ func (m *Model) fields(operation string) (fields []Field) {
 			field.AutoCreateTime = "created_at" == field.DbName
 			field.AutoUpdateTime = "updated_at" == field.DbName
 			value := indirect_value.FieldByName(p.Name)
+			time_value, is_time := value.Interface().(time.Time)
 
 			switch value.Kind() {
 			case reflect.Int, reflect.Int64, reflect.Int32:
@@ -84,15 +85,15 @@ func (m *Model) fields(operation string) (fields []Field) {
 			case reflect.String:
 				field.IsBlank = value.String() == ""
 			default:
-				if value, ok := value.Interface().(time.Time); ok {
+				if is_time {
-					field.IsBlank = value.IsZero()
+					field.IsBlank = time_value.IsZero()
 				}
 			}
 
-			if v, ok := value.Interface().(time.Time); ok {
+			if is_time {
 				switch operation {
 				case "create":
-					if (field.AutoCreateTime || field.AutoUpdateTime) && v.IsZero() {
+					if (field.AutoCreateTime || field.AutoUpdateTime) && time_value.IsZero() {
 						value.Set(reflect.ValueOf(time.Now()))
 					}
 				case "update":
@@ -107,8 +108,16 @@ func (m *Model) fields(operation string) (fields []Field) {
 			if field.IsPrimaryKey {
 				field.SqlType = getPrimaryKeySqlType(m.driver, field.Value, 0)
 			} else {
+				switch reflect.TypeOf(field.Value).Kind() {
+				case reflect.Slice:
+				case reflect.Struct:
+					if is_time {
 						field.SqlType = getSqlType(m.driver, field.Value, 0)
 					}
+				default:
+					field.SqlType = getSqlType(m.driver, field.Value, 0)
+				}
+			}
 			fields = append(fields, field)
 		}
 	}
@@ -165,7 +174,7 @@ func (m *Model) columnsAndValues(operation string) map[string]interface{} {
 
 	results := map[string]interface{}{}
 	for _, field := range m.fields(operation) {
-		if !field.IsPrimaryKey {
+		if !field.IsPrimaryKey && (len(field.SqlType) > 0) {
 			results[field.DbName] = field.Value
 		}
 	}