code: package it.unibz.inf.ontop.generation.algebra;
  
  
  public interface SQLRelationVisitor<T> {
  
      T visit(SelectFromWhereWithModifiers selectFromWhere);
  
      T visit(SQLSerializedQuery sqlSerializedQuery);
  
      T visit(SQLTable sqlTable);
  
      T visit(SQLNaryJoinExpression sqlNaryJoinExpression);
  
      T visit(SQLUnionExpression sqlUnionExpression);
  
      T visit(SQLInnerJoinExpression sqlInnerJoinExpression);
  
      T visit(SQLLeftJoinExpression sqlLeftJoinExpression);
  
      T visit(SQLOneTupleDummyQueryExpression sqlOneTupleDummyQueryExpression);
  
      T visit(SQLValuesExpression sqlValuesExpression);
  
      T visit(SQLFlattenExpression sqlFlattenExpression);
  
  }
  