*********************************************************
*                                                       *
*        DES: Datalog Educational System v.3.0          *
*                                                       *
*                                                       *
* Type "/help" for help about commands                  *
* Type "des." to continue if you get out of DES         *
*   from a Prolog interpreter                           *
*                                                       *
*                    Fernando Saenz-Perez (c) 2004-2011 *
*                                         GPD DISIA UCM *
*             Please send comments, questions, etc. to: *
*                                     fernan@sip.ucm.es *
*                                             Web site: *
*                           http://des.sourceforge.net/ *
*********************************************************

DES> /process examples/SQLDebugger/awards2

Info: Processing file 'examples/SQLDebugger/awards2.sql' ...

DES> -- SQL Debugger


DES> -- November 2011


DES> -- Example 2 Awards


DES> -- Wrong tuple 'Anna'


DES> -- Refer to example2UserTrace.txt for a user trace and example2DevelopmentTrace.txt for a development trace


DES> --


DES> -- Declarative Debugging of Wrong and Missing Answers for SQL Views


DES> -- FLOPS 2012


DES> 


DES> /abolish


DES> /multiline on


DES> /development off

Info: Development listings are already disabled.

DES> -- Turn development on to inspect more info


DES> -- /development on


DES> /* Tables */


DES> DROP TABLE IF EXISTS grants, payment, registration, courses;


DES> CREATE TABLE grants (
   student varchar(45) DEFAULT NULL,
   amount integer default 0
);


DES> CREATE TABLE courses (
  idcourses varchar(11) NOT NULL,
  style varchar(45) DEFAULT NULL,
  level int(11) DEFAULT NULL,
  teacher varchar(10) DEFAULT NULL,
  PRIMARY KEY (`idcourses`)
);


DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c1', 'salsa',    1, 'teach1');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c2', 'salsa',    2, 'teach2');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c3', 'Merengue', 3, 'teach3');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c4', 'salsa',    3, 'teach1');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c5', 'salsa',    3, 'teach1');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c6', 'salsa',    3, 'teach3');

Info: 1 tuple inserted.                     

DES> INSERT INTO `courses` (`idcourses`, `style`, `level`, `teacher`) VALUES ('c7', 'salsa',    0, 'teach1');

Info: 1 tuple inserted.                     

DES> CREATE TABLE registration (
  idregistration int(11) NOT NULL,
  student varchar(45) DEFAULT NULL,
  course varchar(11) DEFAULT NULL,
  PRIMARY KEY (`idregistration`)
);


DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (1, 'Juan', 'c1');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (2, 'Juan', 'c2');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (3, 'Juan', 'c6');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (4, 'Juan', 'c5');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (5, 'Pedro', 'c2');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (6, 'Ana', 'c1');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (7, 'Ana', 'c2');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (8, 'Ana', 'c5');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (9, 'Mica', 'c6');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (10, 'Juan', 'c7');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (11, 'Mica', 'c2');

Info: 1 tuple inserted.                     

DES> INSERT INTO `registration` (`idregistration`, `student`, `course`) VALUES (12, 'Mica', 'c1');

Info: 1 tuple inserted.                     

DES> CREATE TABLE payment (
  `id` int(11) NOT NULL,
  `student` varchar(45) DEFAULT NULL,
  `state` varchar(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
);


DES> INSERT INTO `payment` (`id`, `student`, `state`) VALUES (1, 'Miguel', 'unpaid');

Info: 1 tuple inserted.                     

DES> /* Views */


DES> /* Salsa courses */


DES> create or replace view salsaCourses(id, level, teacher) as
  select c.idcourses, c.level, c.teacher
  from courses c
  where c.style = 'salsa';  


DES> /* Students of salsa courses */


DES> create or replace view salsaStudents(student, level, teacher) as
   select R.student, C.level, C.teacher
   from salsaCourses C, registration R
   where C.id = R.course;


DES> /* Students of intensive course (level = 0) */


DES> create or replace view intensiveStudents(student) as
   select S.student
   from salsaStudents S
   where S.level = 0;


DES> /* Students of first three courses with different teachers */


DES> /* This is the ill-defined view */


DES> create or replace view basicLevelStudents(student) as
select a1.student
from salsaStudents a1, salsaStudents a2, salsaStudents a3 
where a1.student = a2.student and a2.student = a3.student and 
(a1.level = 1) and (a2.level = 2) and (a3.level = 3) and
(a1.teacher <> a2.teacher) and (a2.teacher <> a3.teacher);


DES> /* Students of basic level with different teachers and no intensive level */


DES> /* Two equivalent formulations below (the first one is not accepted by MySQL) */


DES> /*create or replace view candidates(student) as
  select student
  from  basicLevelStudents
except
  select student
  from  intensiveStudents;
*/


DES> create or replace view candidates(student) as
  select student
  from  basicLevelStudents
where student not in (
  select student
  from  intensiveStudents);


DES> /* Candidates with no past due payments */


DES> create or replace view awards(student) as
  select student
  from candidates c
  where  
      c.student not in (select student
                    from payment
                    where state = 'unpaid')
      OR  /* UNION */
      c.student in (select student from grants);


DES> 


Info: Batch file processed.

DES> /verbose on

Info: Verbose output is on.

DES> /development on

Info: Development listings are on.

DES> /debug_sql awards

Info: Question: all(awards)
Info: Debugging view 'awards'.
  SELECT ALL c.student AS $a9
  FROM 
    candidates AS c
  WHERE ((c.student) NOT IN (
      SELECT ALL $t0.student AS $a4
      FROM 
        payment AS $t0
      WHERE $t0.state = 'unpaid' ) OR (c.student) IN (
      SELECT ALL $t2.student AS $a7
      FROM 
        grants AS $t2 ));
Info: Solving query awards(A)...
Info: Computing by stratum of [awards_1_2(A),candidates_1_2(A)].
{                                           
  1 - awards('Ana'),
  2 - awards('Mica')
}
Input: Is this the expected answer for view 'awards'? (y/n/m/mT/w/wN/a/h) [n]: w1
Info: processAnswer(all(awards),wrong(awards(Ana)))
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Computing by stratum of [answer_1_2(A),candidates_1_2(A)].
Info: Processing:                           
  CREATE VIEW candidates_slice1(student) AS
    SELECT ALL *
    FROM 
      candidates AS R
    WHERE EXISTS (
        SELECT ALL candidates.student
        FROM 
          candidates AS c
        WHERE (((c.student) NOT IN (
            SELECT ALL $t0.student AS $a4
            FROM 
              payment AS $t0
            WHERE $t0.state = 'unpaid' ) AND c.student = R.student) AND candidates.student = 'Ana') );
Info: Parsing query...
Info: Query successfully parsed.
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: View created.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Computing by stratum of [candidates_1_2(A)].
Info: Initial logic program:                
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
Info: Solving query basicLevelStudents(A)...
Info: Solving query candidates(A)...        
Info: Computing by stratum of [candidates_1_2(A)].
Info: Solving query courses(A,B,C,D)...     
Info: Solving query grants(A,B)...          
Info: Solving query intensiveStudents(A)... 
Info: Solving query payment(A,B,C)...       
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query candidates_slice1(A)... 
Info: Computing by stratum of [candidates_1_2(A),candidates_slice1_1_4(A)].
Info: Question: all(grants)                 
Info: processAnswer(all(grants),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(grants),valid).

Info: Solving query basicLevelStudents(A)...
Info: Solving query candidates(A)...        
Info: Computing by stratum of [candidates_1_2(A)].
Info: Solving query courses(A,B,C,D)...     
Info: Solving query intensiveStudents(A)... 
Info: Solving query payment(A,B,C)...       
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query candidates_slice1(A)... 
Info: Computing by stratum of [candidates_1_2(A),candidates_slice1_1_4(A)].
Info: Question: all(intensiveStudents)      
Info: Debugging view 'intensiveStudents'.
  SELECT ALL S.student AS $a4
  FROM 
    salsaStudents AS S
  WHERE S.level = 0;
Info: Solving query intensiveStudents(A)...
{                                           
  1 - intensiveStudents('Juan')
}
Input: Is this the expected answer for view 'intensiveStudents'? (y/n/m/mT/w/wN/a/h) [y]: 
Info: processAnswer(all(intensiveStudents),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).

Info: Solving query basicLevelStudents(A)...
Info: Solving query candidates(A)...        
Info: Computing by stratum of [candidates_1_2(A)].
Info: Solving query courses(A,B,C,D)...     
Info: Solving query payment(A,B,C)...       
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query candidates_slice1(A)... 
Info: Computing by stratum of [candidates_1_2(A),candidates_slice1_1_4(A)].
Info: Question: all(payment)                
Info: processAnswer(all(payment),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).

Info: Solving query basicLevelStudents(A)...
Info: Solving query candidates(A)...        
Info: Computing by stratum of [candidates_1_2(A)].
Info: Solving query courses(A,B,C,D)...     
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query candidates_slice1(A)... 
Info: Computing by stratum of [candidates_1_2(A),candidates_slice1_1_4(A)].
Info: Question: subset(candidates_slice1,candidates)
Info: Solving query candidates_slice1(A)...
Info: Computing by stratum of [candidates_1_2(A),candidates_slice1_1_4(A)].
Info: Debugging view 'candidates'.          
  SELECT ALL $t2.student AS $a3
  FROM 
    basicLevelStudents AS $t2
  WHERE ($t2.student) NOT IN (
      SELECT ALL $t0.student AS $a1
      FROM 
        intensiveStudents AS $t0 );
Input: Should 'candidates' include a tuple of the form 'Ana'? (y/n/a) [y]: n
Info: processAnswer(subset(candidates_slice1,candidates),wrong(candidates(Ana)))
Info: processAnswer(all(candidates),wrong(candidates(Ana)))
Info: Processing:
  CREATE VIEW basicLevelStudents_slice1(student) AS
    SELECT ALL *
    FROM 
      basicLevelStudents AS R
    WHERE EXISTS (
        SELECT ALL basicLevelStudents.student
        FROM 
          basicLevelStudents AS $t2
        WHERE ((($t2.student) NOT IN (
            SELECT ALL $t0.student AS $a1
            FROM 
              intensiveStudents AS $t0 ) AND $t2.student = R.student) AND basicLevelStudents.student = 'Ana') );
Info: Parsing query...
Info: Query successfully parsed.
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: View created.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(candidates_slice1,candidates),nonvalid).

Info: Solving query basicLevelStudents(A)...
Info: Solving query courses(A,B,C,D)...     
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query basicLevelStudents_slice1(A)...
Info: Computing by stratum of [basicLevelStudents_slice1_1_4(A)].
Info: Question: subset(basicLevelStudents_slice1,basicLevelStudents)
Info: Solving query basicLevelStudents_slice1(A)...
Info: Computing by stratum of [basicLevelStudents_slice1_1_4(A)].
Info: Debugging view 'basicLevelStudents'.  
  SELECT ALL a1.student AS $a20
  FROM 
    salsaStudents AS a1, 
    salsaStudents AS a2, 
    salsaStudents AS a3
  WHERE ((((((a1.student = a2.student AND a2.student = a3.student) AND a1.level = 1) AND a2.level = 2) AND a3.level = 3) AND a1.teacher <> a2.teacher) AND a2.teacher <> a3.teacher);
Input: Should 'basicLevelStudents' include a tuple of the form 'Ana'? (y/n/a) [y]: n
Info: processAnswer(subset(basicLevelStudents_slice1,basicLevelStudents),wrong(basicLevelStudents(Ana)))
Info: processAnswer(all(basicLevelStudents),wrong(basicLevelStudents(Ana)))
Info: Processing:
  CREATE VIEW salsaStudents_slice1(student,level,teacher) AS
    SELECT ALL *
    FROM 
      salsaStudents AS R
    WHERE EXISTS (
        SELECT ALL salsaStudents.student
        FROM 
          salsaStudents AS a1, 
          salsaStudents AS a2, 
          salsaStudents AS a3
        WHERE ((((((((a1.student = a2.student AND a2.student = a3.student) AND a1.level = 1) AND a2.level = 2) AND a3.level = 3) AND a1.teacher <> a2.teacher) AND a2.teacher <> a3.teacher) AND (a1.student = R.student AND (a1.level = R.level AND a1.teacher = R.teacher))) AND salsaStudents.student = 'Ana') );
Info: Parsing query...
Info: Query successfully parsed.
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: View created.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Processing:
  CREATE VIEW salsaStudents_slice2(student,level,teacher) AS
    SELECT ALL *
    FROM 
      salsaStudents AS R
    WHERE EXISTS (
        SELECT ALL salsaStudents.student
        FROM 
          salsaStudents AS a1, 
          salsaStudents AS a2, 
          salsaStudents AS a3
        WHERE ((((((((a1.student = a2.student AND a2.student = a3.student) AND a1.level = 1) AND a2.level = 2) AND a3.level = 3) AND a1.teacher <> a2.teacher) AND a2.teacher <> a3.teacher) AND (a2.student = R.student AND (a2.level = R.level AND a2.teacher = R.teacher))) AND salsaStudents.student = 'Ana') );
Info: Parsing query...
Info: Query successfully parsed.
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: View created.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Processing:
  CREATE VIEW salsaStudents_slice3(student,level,teacher) AS
    SELECT ALL *
    FROM 
      salsaStudents AS R
    WHERE EXISTS (
        SELECT ALL salsaStudents.student
        FROM 
          salsaStudents AS a1, 
          salsaStudents AS a2, 
          salsaStudents AS a3
        WHERE ((((((((a1.student = a2.student AND a2.student = a3.student) AND a1.level = 1) AND a2.level = 2) AND a3.level = 3) AND a1.teacher <> a2.teacher) AND a2.teacher <> a3.teacher) AND (a3.student = R.student AND (a3.level = R.level AND a3.teacher = R.teacher))) AND salsaStudents.student = 'Ana') );
Info: Parsing query...
Info: Query successfully parsed.
Info: Compiling SQL statement to Datalog rules...
Info: SQL statement successfully compiled.
Info: View created.
Info: Computing predicate dependency graph...
Info: Computing strata...
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(basicLevelStudents) :-
    state(subset(salsaStudents_slice1,salsaStudents),valid),
    state(subset(salsaStudents_slice2,salsaStudents),valid),
    state(subset(salsaStudents_slice3,salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(basicLevelStudents),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(basicLevelStudents_slice1,basicLevelStudents),nonvalid).
  state(subset(candidates_slice1,candidates),nonvalid).

Info: Solving query courses(A,B,C,D)...
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query salsaStudents_slice1(A,B,C)...
Info: Solving query salsaStudents_slice2(A,B,C)...
Info: Solving query salsaStudents_slice3(A,B,C)...
Info: Question: subset(salsaStudents_slice1,salsaStudents)
Info: Solving query salsaStudents_slice1(A,B,C)...
Info: Debugging view 'salsaStudents'.       
  SELECT ALL R.student AS $a8, C.level AS $a9, C.teacher AS $a10
  FROM 
    salsaCourses AS C, 
    registration AS R
  WHERE C.id = R.course;
Input: Should 'salsaStudents' include a tuple of the form 'Ana,1,teach1'? (y/n/a) [y]: 
Info: processAnswer(subset(salsaStudents_slice1,salsaStudents),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(basicLevelStudents) :-
    state(subset(salsaStudents_slice1,salsaStudents),valid),
    state(subset(salsaStudents_slice2,salsaStudents),valid),
    state(subset(salsaStudents_slice3,salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(basicLevelStudents),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(basicLevelStudents_slice1,basicLevelStudents),nonvalid).
  state(subset(candidates_slice1,candidates),nonvalid).
  state(subset(salsaStudents_slice1,salsaStudents),valid).

Info: Solving query courses(A,B,C,D)...
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query salsaStudents_slice2(A,B,C)...
Info: Solving query salsaStudents_slice3(A,B,C)...
Info: Question: subset(salsaStudents_slice2,salsaStudents)
Info: Solving query salsaStudents_slice2(A,B,C)...
Info: Debugging view 'salsaStudents'.       
  SELECT ALL R.student AS $a8, C.level AS $a9, C.teacher AS $a10
  FROM 
    salsaCourses AS C, 
    registration AS R
  WHERE C.id = R.course;
Input: Should 'salsaStudents' include a tuple of the form 'Ana,2,teach2'? (y/n/a) [y]: 
Info: processAnswer(subset(salsaStudents_slice2,salsaStudents),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(basicLevelStudents) :-
    state(subset(salsaStudents_slice1,salsaStudents),valid),
    state(subset(salsaStudents_slice2,salsaStudents),valid),
    state(subset(salsaStudents_slice3,salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(basicLevelStudents),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(basicLevelStudents_slice1,basicLevelStudents),nonvalid).
  state(subset(candidates_slice1,candidates),nonvalid).
  state(subset(salsaStudents_slice1,salsaStudents),valid).
  state(subset(salsaStudents_slice2,salsaStudents),valid).

Info: Solving query courses(A,B,C,D)...
Info: Solving query registration(A,B,C)...  
Info: Solving query salsaCourses(A,B,C)...  
Info: Solving query salsaStudents(A,B,C)... 
Info: Solving query salsaStudents_slice3(A,B,C)...
Info: Question: subset(salsaStudents_slice3,salsaStudents)
Info: Solving query salsaStudents_slice3(A,B,C)...
Info: Debugging view 'salsaStudents'.       
  SELECT ALL R.student AS $a8, C.level AS $a9, C.teacher AS $a10
  FROM 
    salsaCourses AS C, 
    registration AS R
  WHERE C.id = R.course;
Input: Should 'salsaStudents' include a tuple of the form 'Ana,3,teach1'? (y/n/a) [y]: 
Info: processAnswer(subset(salsaStudents_slice3,salsaStudents),valid)
Info: Current logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(basicLevelStudents) :-
    state(subset(salsaStudents_slice1,salsaStudents),valid),
    state(subset(salsaStudents_slice2,salsaStudents),valid),
    state(subset(salsaStudents_slice3,salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(basicLevelStudents),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(basicLevelStudents_slice1,basicLevelStudents),nonvalid).
  state(subset(candidates_slice1,candidates),nonvalid).
  state(subset(salsaStudents_slice1,salsaStudents),valid).
  state(subset(salsaStudents_slice2,salsaStudents),valid).
  state(subset(salsaStudents_slice3,salsaStudents),valid).

Info: Final logic program:
  buggy(awards) :-
    state(all(awards),nonvalid),
    state(all(candidates),valid),
    state(all(grants),valid),
    state(all(payment),valid).
  buggy(awards) :-
    state(subset(candidates_slice1,candidates),valid),
    state(all(payment),valid).
  buggy(basicLevelStudents) :-
    state(all(basicLevelStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(basicLevelStudents) :-
    state(subset(salsaStudents_slice1,salsaStudents),valid),
    state(subset(salsaStudents_slice2,salsaStudents),valid),
    state(subset(salsaStudents_slice3,salsaStudents),valid).
  buggy(candidates) :-
    state(all(candidates),nonvalid),
    state(all(basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(candidates) :-
    state(subset(basicLevelStudents_slice1,basicLevelStudents),valid),
    state(all(intensiveStudents),valid).
  buggy(courses) :-
    state(all(courses),nonvalid).
  buggy(grants) :-
    state(all(grants),nonvalid).
  buggy(intensiveStudents) :-
    state(all(intensiveStudents),nonvalid),
    state(all(salsaStudents),valid).
  buggy(payment) :-
    state(all(payment),nonvalid).
  buggy(registration) :-
    state(all(registration),nonvalid).
  buggy(salsaCourses) :-
    state(all(salsaCourses),nonvalid),
    state(all(courses),valid).
  buggy(salsaStudents) :-
    state(all(salsaStudents),nonvalid),
    state(all(registration),valid),
    state(all(salsaCourses),valid).
  state(all(awards),nonvalid).
  state(all(basicLevelStudents),nonvalid).
  state(all(candidates),nonvalid).
  state(all(grants),valid).
  state(all(intensiveStudents),valid).
  state(all(payment),valid).
  state(subset(basicLevelStudents_slice1,basicLevelStudents),nonvalid).
  state(subset(candidates_slice1,candidates),nonvalid).
  state(subset(salsaStudents_slice1,salsaStudents),valid).
  state(subset(salsaStudents_slice2,salsaStudents),valid).
  state(subset(salsaStudents_slice3,salsaStudents),valid).

Info: Buggy view found: basicLevelStudents
Info: View 'candidates_slice1' dropped.
Info: View 'basicLevelStudents_slice1' dropped.
Info: View 'salsaStudents_slice1' dropped.
Info: View 'salsaStudents_slice2' dropped.
Info: View 'salsaStudents_slice3' dropped.

DES>