Practica 2

practicas/prac2/03_create_squema.sql

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+create table departamento(
+cod_dep char(5) not null constraint cp_dep primary key initially immediate deferrable,
+nombre varchar(40) not null,
+director varchar(20),
+telefono char(15));
+
+create table profesor(
+cod_pro char(5) not null constraint cp_prof primary key initially immediate deferrable,
+nombre varchar(40) not null,
+telefono char(15),
+cod_dep char(5) constraint ca_prof_dep references departamento(cod_dep) initially immediate deferrable);
+
+create table asignatura(
+cod_asg char(5) not null constraint cp_asi primary key initially immediate deferrable,
+nombre varchar(40) not null,
+semestre char(2) not null,
+teoria number(3,1) not null,
+prac number(3,1) not null,
+cod_dep char(5) constraint ca_asi_dep references departamento(cod_dep) initially immediate deferrable);
+
+create table docencia(
+cod_pro char(5) not null constraint ca_doc_prof references profesor(cod_pro) initially immediate deferrable,
+cod_asg char(5) not null constraint ca_doc_asi references asignatura(cod_asg) initially immediate deferrable,
+gteo number(2) not null,
+gprac number(2) not null,
+constraint cp_doc primary key(cod_pro, cod_asg) initially immediate deferrable);
+

practicas/prac2/05_populate_squema.sql

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+insert into departamento values('DSIC','Sistemas Informaticos y Computacion','V. Botti','3500');
+insert into departamento values('DISCA','Ingenieria de Sistemas y Automatica','A. Crespo','6400');
+insert into profesor values('JCC','Juan Carlos Casamayor','3523','DSIC');
+insert into profesor values('MCG','Matilde Celma Gimenez','3234','DSIC');
+insert into profesor values('MAP','Maria Pastor','3666','DISCA');
+insert into asignatura values('BDA','Bases de Datos','2B',3,3,'DSIC');
+insert into asignatura values('AD3','Algoritmos y Estructuras de Datos III','2B',3,3,'DSIC');
+insert into asignatura values('BDV','Bases de Datos Avanzadas','5A',3,3,'DSIC');
+insert into asignatura values('APB','Desarrollo de aplicaciones de BD','3B',3,3,'DSIC');
+insert into asignatura values('SO','Sistemas Operativos','2A',3,3,'DISCA');
+insert into docencia values('MCG','SO',1,1);
+insert into docencia values('MCG','BDA',2,1);
+insert into docencia values('MCG','AD3',1,1);
+insert into docencia values('JCC','BDA',1,2);
+insert into docencia values('MAP','BDA',1,2);
+insert into docencia values('MAP','BDV',1,2);
+commit;
+

practicas/prac2/06_create_views.sql

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+CREATE VIEW prof_dsic AS SELECT
+    cod_pro, nombre, telefono
+FROM
+    profesor
+WHERE
+    cod_dep = 'DSIC';
+    
+CREATE VIEW docencia_dsic AS SELECT
+    prof_dsic.cod_pro, prof_dsic.nombre AS nombre_pro, asignatura.cod_asg,
+    asignatura.nombre AS nombre_asg, gteo, gprac
+FROM
+    prof_dsic, asignatura, docencia
+WHERE
+    prof_dsic.cod_pro = docencia.cod_pro AND
+    docencia.cod_asg  = asignatura.cod_asg;
+
+CREATE VIEW asg_dsic AS SELECT
+    asignatura.cod_asg, nombre_asg as nombre, semestre, teoria, prac,
+    COUNT(DISTINCT cod_pro) AS profesores, SUM(gteo + gprac) AS creditos
+FROM
+    docencia_dsic JOIN asignatura ON docencia_dsic.cod_asg = asignatura.cod_asg
+GROUP BY nombre_asg, semestre, teoria, prac, asignatura.cod_asg;

practicas/prac2/08_view_insert_trigger.sql

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+CREATE OR REPLACE TRIGGER prof_dsic_insert_trigger
+INSTEAD OF INSERT ON prof_dsic
+FOR EACH ROW
+BEGIN
+INSERT INTO profesor VALUES (:NEW.cod_pro, :NEW.nombre, :NEW.telefono, 'DSIC');
+END;
+/
+
+-- Probar disparador (ver insercion antes y despues)
+INSERT INTO prof_dsic VALUES ('pp', 'Pepe', '963123123');
+DELETE FROM prof_dsic WHERE cod_pro = 'pp';
+DELETE FROM profesor WHERE cod_pro = 'pp';

practicas/prac2/09_mod_constraints.sql

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+INSERT INTO PROFESOR(cod_pro, nombre) VALUES('JR', 'Juan Ruiz');
+-- Fails here, constraint is INITIALLY IMMEDIATE
+INSERT INTO PROFESOR(cod_pro, nombre) VALUES('JR', 'Javier Pérez');
+ROLLBACK; -- Don't save the first insertion
+
+-- Change constraint to be INITIALLY DEFERRED
+ALTER TABLE profesor DROP PRIMARY KEY CASCADE KEEP INDEX;
+ALTER TABLE profesor ADD CONSTRAINT cp_prof PRIMARY KEY(cod_pro) INITIALLY DEFERRED DEFERRABLE;
+-- Because we used CASCADE to DROP the primary key constraint,
+-- we need to restore the FOREIGN KEY in docencia
+ALTER TABLE docencia
+	ADD CONSTRAINT ca_doc_prof
+	FOREIGN KEY(cod_pro) REFERENCES profesor(cod_pro) INITIALLY IMMEDIATE DEFERRABLE;
+
+INSERT INTO PROFESOR(cod_pro, nombre) VALUES('JR', 'Juan Ruiz');
+INSERT INTO PROFESOR(cod_pro, nombre) VALUES('JR', 'Javier Pérez');
+-- Fails here, constraint is INITIALLY DEFERRED
+COMMIT;
+
+-- Restore constraint to initial setting
+ALTER TABLE profesor DROP PRIMARY KEY CASCADE KEEP INDEX;
+ALTER TABLE profesor ADD CONSTRAINT cp_prof PRIMARY KEY(cod_pro) INITIALLY IMMEDIATE DEFERRABLE;
+ALTER TABLE docencia ADD CONSTRAINT ca_doc_prof FOREIGN KEY(cod_pro) REFERENCES profesor(cod_pro) INITIALLY IMMEDIATE DEFERRABLE;
+

practicas/prac2/10_cascade_trigger.sql

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+-- In WHEN, NEW and OLD don't need the colon
+
+-- Update docencia.cod_pro when profesor.cod_pro changes
+CREATE OR REPLACE TRIGGER cascade_profesor_update
+AFTER UPDATE ON profesor
+FOR EACH ROW
+WHEN (OLD.cod_pro <> NEW.cod_pro)
+BEGIN
+    UPDATE docencia
+    SET cod_pro = :new.cod_pro
+    WHERE cod_pro = :old.cod_pro;
+END;
+/
+
+-- Delete entries from docencia when profesor is deleted
+CREATE OR REPLACE TRIGGER cascade_profesor_delete
+AFTER DELETE ON profesor
+FOR EACH ROW
+BEGIN
+    DELETE FROM docencia
+    WHERE cod_pro = :old.cod_pro;
+END;
+/