try {
Image image = OBDal.getInstance().get(Image.class, imageID);
Table table = OBDal.getInstance().get(Table.class, tableId);
String propertyName = ModelProvider.getInstance().getEntityByTableName(
table.getDBTableName()).getPropertyByColumnName(columnName).getName();
DataPackage dpackage = table.getDataPackage();
try {
Class tableClass = Class.forName(dpackage.getJavaPackage() + "."
+ table.getJavaClassName());
BaseOBObject parentObject = (BaseOBObject) OBDal.getInstance().get(tableClass,
parentObjectId);
parentObject.set(propertyName, null);
OBDal.getInstance().flush();