code: public int removeMetadataParent(long parentId) throws SQLException {
  
  		UpdateBuilder<MetadataReference, Void> ub = updateBuilder();
  		ub.updateColumnValue(MetadataReference.COLUMN_PARENT_ID, null);
  
  		ub.where().eq(MetadataReference.COLUMN_PARENT_ID, parentId);
  
  		PreparedUpdate<MetadataReference> update = ub.prepare();
  		int updated = update(update);
  
  		return updated;
  	}
docs: Remove metadata references (by updating the field to null) with foreign
  keys to the metadata parent id
  
  @param parentId
  parent id
  @return updated count
  @throws SQLException
  upon failure