diff --git a/session.go b/session.go
index 1e33541a..3fb92991 100644
--- a/session.go
+++ b/session.go
@@ -437,7 +437,7 @@ func (session *Session) row2Slice(rows *core.Rows, fields []string, bean interfa
 }
 
 func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflect.Value,
-	scanResult interface{}, dataStruct *reflect.Value, table *schemas.Table) error {
+	scanResult interface{}, table *schemas.Table) error {
 	rawValue := reflect.Indirect(reflect.ValueOf(scanResult))
 
 	// if row is null then ignore
@@ -474,7 +474,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 	vv := reflect.ValueOf(rawValue.Interface())
 
 	fieldType := fieldValue.Type()
-	hasAssigned := false
 
 	if col.IsJSON {
 		var bs []byte
@@ -486,8 +485,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 			return fmt.Errorf("unsupported database data type: %s %v", col.Name, rawValueType.Kind())
 		}
 
-		hasAssigned = true
-
 		if len(bs) > 0 {
 			if fieldType.Kind() == reflect.String {
 				fieldValue.SetString(string(bs))
@@ -507,7 +504,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 				fieldValue.Set(x.Elem())
 			}
 		}
-
 		return nil
 	}
 
@@ -521,7 +517,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 			bs = vv.Bytes()
 		}
 
-		hasAssigned = true
 		if len(bs) > 0 {
 			if fieldValue.CanAddr() {
 				err := json.DefaultJSONHandler.Unmarshal(bs, fieldValue.Addr().Interface())
@@ -537,13 +532,13 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 				fieldValue.Set(x.Elem())
 			}
 		}
+		return nil
 	case reflect.Slice, reflect.Array:
 		switch rawValueType.Kind() {
 		case reflect.Slice, reflect.Array:
 			switch rawValueType.Elem().Kind() {
 			case reflect.Uint8:
 				if fieldType.Elem().Kind() == reflect.Uint8 {
-					hasAssigned = true
 					if col.SQLType.IsText() {
 						x := reflect.New(fieldType)
 						err := json.DefaultJSONHandler.Unmarshal(vv.Bytes(), x.Interface())
@@ -564,39 +559,40 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 							}
 						}
 					}
+					return nil
 				}
 			}
 		}
 	case reflect.String:
 		if rawValueType.Kind() == reflect.String {
-			hasAssigned = true
 			fieldValue.SetString(vv.String())
+			return nil
 		}
 	case reflect.Bool:
 		if rawValueType.Kind() == reflect.Bool {
-			hasAssigned = true
 			fieldValue.SetBool(vv.Bool())
+			return nil
 		}
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		switch rawValueType.Kind() {
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			hasAssigned = true
 			fieldValue.SetInt(vv.Int())
+			return nil
 		}
 	case reflect.Float32, reflect.Float64:
 		switch rawValueType.Kind() {
 		case reflect.Float32, reflect.Float64:
-			hasAssigned = true
 			fieldValue.SetFloat(vv.Float())
+			return nil
 		}
 	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint:
 		switch rawValueType.Kind() {
 		case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint:
-			hasAssigned = true
 			fieldValue.SetUint(vv.Uint())
+			return nil
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			hasAssigned = true
 			fieldValue.SetUint(uint64(vv.Int()))
+			return nil
 		}
 	case reflect.Struct:
 		if fieldType.ConvertibleTo(schemas.TimeType) {
@@ -606,8 +602,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 			}
 
 			if rawValueType == schemas.TimeType {
-				hasAssigned = true
-
 				t := vv.Convert(schemas.TimeType).Interface().(time.Time)
 
 				z, _ := t.Zone()
@@ -620,45 +614,42 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 
 				t = t.In(session.engine.TZLocation)
 				fieldValue.Set(reflect.ValueOf(t).Convert(fieldType))
+				return nil
 			} else if rawValueType == schemas.IntType || rawValueType == schemas.Int64Type ||
 				rawValueType == schemas.Int32Type {
-				hasAssigned = true
-
 				t := time.Unix(vv.Int(), 0).In(session.engine.TZLocation)
 				fieldValue.Set(reflect.ValueOf(t).Convert(fieldType))
+				return nil
 			} else {
 				if d, ok := vv.Interface().([]uint8); ok {
-					hasAssigned = true
 					t, err := session.byte2Time(col, d)
 					if err != nil {
 						session.engine.logger.Errorf("byte2Time error: %v", err)
-						hasAssigned = false
 					} else {
 						fieldValue.Set(reflect.ValueOf(t).Convert(fieldType))
+						return nil
 					}
+
 				} else if d, ok := vv.Interface().(string); ok {
-					hasAssigned = true
 					t, err := session.str2Time(col, d)
 					if err != nil {
 						session.engine.logger.Errorf("byte2Time error: %v", err)
-						hasAssigned = false
 					} else {
 						fieldValue.Set(reflect.ValueOf(t).Convert(fieldType))
+						return nil
 					}
 				} else {
 					return fmt.Errorf("rawValueType is %v, value is %v", rawValueType, vv.Interface())
 				}
 			}
 		} else if nulVal, ok := fieldValue.Addr().Interface().(sql.Scanner); ok {
-			// !<winxxp>! 增加支持sql.Scanner接口的结构，如sql.NullString
-			hasAssigned = true
-			if err := nulVal.Scan(vv.Interface()); err != nil {
-				session.engine.logger.Errorf("sql.Sanner error: %v", err)
-				hasAssigned = false
+			err := nulVal.Scan(vv.Interface())
+			if err == nil {
+				return nil
 			}
+			session.engine.logger.Errorf("sql.Sanner error: %v", err)
 		} else if col.IsJSON {
 			if rawValueType.Kind() == reflect.String {
-				hasAssigned = true
 				x := reflect.New(fieldType)
 				if len([]byte(vv.String())) > 0 {
 					err := json.DefaultJSONHandler.Unmarshal([]byte(vv.String()), x.Interface())
@@ -667,8 +658,8 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 					}
 					fieldValue.Set(x.Elem())
 				}
+				return nil
 			} else if rawValueType.Kind() == reflect.Slice {
-				hasAssigned = true
 				x := reflect.New(fieldType)
 				if len(vv.Bytes()) > 0 {
 					err := json.DefaultJSONHandler.Unmarshal(vv.Bytes(), x.Interface())
@@ -677,6 +668,7 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 					}
 					fieldValue.Set(x.Elem())
 				}
+				return nil
 			}
 		} else if session.statement.UseCascade {
 			table, err := session.engine.tagParser.ParseWithCache(*fieldValue)
@@ -684,7 +676,6 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 				return err
 			}
 
-			hasAssigned = true
 			if len(table.PrimaryKeys) != 1 {
 				return errors.New("unsupported non or composited primary key cascade")
 			}
@@ -709,6 +700,7 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 					return errors.New("cascade obj is not exist")
 				}
 			}
+			return nil
 		}
 	case reflect.Ptr:
 		// !nashtsai! TODO merge duplicated codes above
@@ -717,92 +709,92 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 		case schemas.PtrStringType:
 			if rawValueType.Kind() == reflect.String {
 				x := vv.String()
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrBoolType:
 			if rawValueType.Kind() == reflect.Bool {
 				x := vv.Bool()
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrTimeType:
 			if rawValueType == schemas.PtrTimeType {
-				hasAssigned = true
 				var x = rawValue.Interface().(time.Time)
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrFloat64Type:
 			if rawValueType.Kind() == reflect.Float64 {
 				x := vv.Float()
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrUint64Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = uint64(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrInt64Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				x := vv.Int()
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrFloat32Type:
 			if rawValueType.Kind() == reflect.Float64 {
 				var x = float32(vv.Float())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrIntType:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = int(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrInt32Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = int32(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrInt8Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = int8(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrInt16Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = int16(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrUintType:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = uint(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.PtrUint32Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = uint32(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.Uint8Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = uint8(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.Uint16Type:
 			if rawValueType.Kind() == reflect.Int64 {
 				var x = uint16(vv.Int())
-				hasAssigned = true
 				fieldValue.Set(reflect.ValueOf(&x))
+				return nil
 			}
 		case schemas.Complex64Type:
 			var x complex64
@@ -813,7 +805,7 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 				}
 				fieldValue.Set(reflect.ValueOf(&x))
 			}
-			hasAssigned = true
+			return nil
 		case schemas.Complex128Type:
 			var x complex128
 			if len([]byte(vv.String())) > 0 {
@@ -823,23 +815,16 @@ func (session *Session) convertBeanField(col *schemas.Column, fieldValue *reflec
 				}
 				fieldValue.Set(reflect.ValueOf(&x))
 			}
-			hasAssigned = true
+			return nil
 		} // switch fieldType
 	} // switch fieldType.Kind()
 
-	if hasAssigned {
-		return nil
-	}
-
 	data, err := value2Bytes(&rawValue)
 	if err != nil {
 		return err
 	}
 
-	if err = session.bytes2Value(col, fieldValue, data); err != nil {
-		return err
-	}
-	return nil
+	return session.bytes2Value(col, fieldValue, data)
 }
 
 func (session *Session) slice2Bean(scanResults []interface{}, fields []string, bean interface{}, dataStruct *reflect.Value, table *schemas.Table) (schemas.PK, error) {
@@ -878,7 +863,7 @@ func (session *Session) slice2Bean(scanResults []interface{}, fields []string, b
 			continue
 		}
 
-		if err := session.convertBeanField(col, fieldValue, scanResult, dataStruct, table); err != nil {
+		if err := session.convertBeanField(col, fieldValue, scanResult, table); err != nil {
 			return nil, err
 		}
 		if col.IsPrimaryKey {