enhance(report):批量导入预置的维护费功能，会提前删除之前导入的内容。

controller/report.go

@@ -291,7 +291,7 @@ func importPredefinedMaintenanceFees(c *gin.Context) {
 			return *fee
 		},
 	)
-	err = service.ReportService.BatchSaveMaintenanceFee(dilutedFees)
+	err = service.ReportService.BatchSaveMaintenanceFee(report.Id, dilutedFees)
 	if err != nil {
 		result.Error(http.StatusInternalServerError, err.Error())
 		return

service/report.go

@@ -220,13 +220,21 @@ func (_ReportService) CreateTemporaryWillDilutedMaintenanceFee(fee model.WillDil
 	return err
 }
 
-func (_ReportService) BatchSaveMaintenanceFee(fees []model.WillDilutedFee) error {
+func (_ReportService) BatchSaveMaintenanceFee(reportId string, fees []model.WillDilutedFee) error {
 	tx := global.DBConn.NewSession()
 	if err := tx.Begin(); err != nil {
 		return err
 	}
 	defer tx.Close()
-	_, err := tx.Insert(fees)
+	// 首先删除所有预定义的部分，条件是指定报表ID，SourceID不为空。
+	cond := builder.Eq{"report_id": reportId}.And(builder.NotNull{"source_id"})
+	_, err := tx.Table(new(model.WillDilutedFee)).Where(cond).Delete()
+	if err != nil {
+		tx.Rollback()
+		return err
+	}
+	// 然后插入新的记录
+	_, err = tx.Insert(fees)
 	if err != nil {
 		return err
 	}