386 lines
10 KiB
MySQL
386 lines
10 KiB
MySQL
-- Aufgabe 7.1
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DECLARE
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v_num NUMBER := &sv_num;
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BEGIN
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DBMS_OUTPUT.PUT_LINE ('Square root of '||v_num||
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' is '||SQRT(v_num));
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('An error has occurred');
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END;
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/
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--a) Was wird ausgegeben, wenn das Skript einmal mit 4 und -4 ausgeführt wird
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-- 4: Square root of 4 is 2
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-- -4: An error has occured
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--b) Wieso ist der zweite Durchlauf anders?
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-- Der zweite Durchlauf ist anders, weil die Funktion SQRT keine negative Zahlen akzeptiert.
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--c) Angenommen es gibt keine VALUE-ERROR Exception. Wie müsste das Skript umgebaut werden, um den Fehler zu behandeln/vermeiden?
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-- Man müsste mit einem IF vorher schauen, ob die Zahl negativ ist.
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-- Aufgabe 7.2
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DECLARE
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v_exists NUMBER(1);
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v_total_students NUMBER(1);
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v_zip CHAR(5):= '&sv_zip';
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BEGIN
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SELECT count(*)
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INTO v_exists
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FROM zipcode
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WHERE zip = v_zip;
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IF v_exists != 0 THEN
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SELECT COUNT(*)
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INTO v_total_students
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FROM student
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WHERE zip = v_zip;
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DBMS_OUTPUT.PUT_LINE('There are '||v_total_students||' students');
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ELSE
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DBMS_OUTPUT.PUT_LINE (v_zip||' is not a valid zip');
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END IF;
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EXCEPTION
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WHEN VALUE_ERROR OR INVALID_NUMBER THEN
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DBMS_OUTPUT.PUT_LINE ('An error has occurred');
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END;
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/
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--a) Was wird ausgegeben, wenn das Skript für 07024, 00914 und 12345 aufgerufen wird.
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-- 07024: There are 1 students
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-- 00914: 00914 is not a valid zip
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-- 12345: 12345 is not a valid zip
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--b) Wieso wurde keine Exception geworfen?
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-- Da wir vorher im IF geschaut haben, ob die Zahl existiert und wir auch das richtige Format eingegeben haben.
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--c) Füge folgenden Studenten hinzu
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INSERT INTO student (student_id, salutation, first_name,
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last_name, zip, registration_date, created_by, created_date,
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modified_by, modified_date)
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VALUES (STUDENT_ID_SEQ.NEXTVAL, 'Mr.', 'John', 'Smith', '07024',
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SYSDATE, 'STUDENT', SYSDATE, 'STUDENT', SYSDATE); COMMIT;
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--d) Führe nach dem Hinzufügen aus Schritt c. das Skript mit 07024 aus. Wieso ändert sich jetzt das Ergebnis?
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-- Error, weil Exists nur eine Stelle hat und der eingefügt Student der 10. existierende Schüler wäre.
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--e)Ändere das Skript so, dass nun Vor- und Nachname des ersten Studenten für die angegeben
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--PLZ anstelle der Gesamtanzahl ausgegeben wird. (vgl. rownum) — Achte dabei auf korrektes
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--Error-Handling!
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DECLARE
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v_exists NUMBER(1);
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v_first_name VARCHAR2(50);
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v_last_name VARCHAR2(50);
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v_zip CHAR(5) := '&sv_zip';
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BEGIN
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SELECT count(*)
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INTO v_exists
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FROM zipcode
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WHERE zip = v_zip;
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IF v_exists != 0 THEN
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BEGIN
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SELECT first_name, last_name
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INTO v_first_name, v_last_name
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FROM STUDENT
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WHERE zip = v_zip AND ROWNUM = 1;
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DBMS_OUTPUT.PUT_LINE('First student: ' || v_first_name || ' ' || v_last_name);
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EXCEPTION
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WHEN NO_DATA_FOUND THEN
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DBMS_OUTPUT.PUT_LINE('No students found for zip ' || v_zip);
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END;
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ELSE
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DBMS_OUTPUT.PUT_LINE(v_zip || ' is not a valid zip');
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END IF;
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EXCEPTION
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WHEN VALUE_ERROR OR INVALID_NUMBER THEN
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DBMS_OUTPUT.PUT_LINE('An error has occurred');
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END;
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/
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-- Aufgabe 7.3
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DECLARE
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v_student_id NUMBER(10) := '&sv_user_id';
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v_first_name VARCHAR2(50);
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BEGIN
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SELECT first_name
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INTO v_first_name
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FROM STUDENT
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WHERE student_id = v_student_id;
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DBMS_OUTPUT.PUT_LINE('Is here: ' || v_first_name);
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EXCEPTION
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WHEN NO_DATA_FOUND THEN
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INSERT INTO student (STUDENT_ID, salutation, first_name,
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last_name, zip, registration_date, created_by, created_date,
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modified_by, modified_date)
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VALUES (v_student_id, 'Mr.', 'John', 'Smith', '07024',
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SYSDATE, 'STUDENT', SYSDATE, 'STUDENT', SYSDATE); COMMIT;
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END;
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/
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-- Aufgabe 7.4
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DECLARE
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v_instructor_id NUMBER := &sv_instructor_id;
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v_sections_count NUMBER;
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v_firstname VARCHAR2(50);
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BEGIN
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SELECT COUNT(*), first_name
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INTO v_sections_count, v_firstname
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FROM instructor
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INNER JOIN SECTION USING(instructor_id)
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WHERE instructor_id = v_instructor_id
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GROUP BY first_name;
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DBMS_OUTPUT.PUT_LINE('Sections: ' || v_sections_count);
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EXCEPTION
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WHEN NO_DATA_FOUND THEN
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DBMS_OUTPUT.PUT_LINE('No data found for instructor ID: ' || v_instructor_id);
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WHEN OTHERS THEN
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DBMS_OUTPUT.PUT_LINE('An error has occurred');
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END;
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/
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-- Aufgabe 7.5
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DECLARE
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v_zip VARCHAR2(5) := '&sv_zip';
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v_total NUMBER(1);
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-- outer block
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BEGIN
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DBMS_OUTPUT.PUT_LINE ('Check if provided zipcode is valid');
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SELECT zip
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INTO v_zip
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FROM zipcode
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WHERE zip = v_zip;
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-- inner block
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BEGIN
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SELECT count(*)
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INTO v_total
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FROM student
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WHERE zip = v_zip;
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DBMS_OUTPUT.PUT_LINE ('There are '||v_total||' students for zipcode '||v_zip);
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END;
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DBMS_OUTPUT.PUT_LINE ('Done...');
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END;
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/
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--a) Was wird ausgegeben, wenn das Skript für 07024 ausgeführt wird?
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-- Es soll die v_total auf NUMBER(2) oder höher geändert werden, sodass kein Error mehr kommt. Danach würde folgendes ausgegeben werden:
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--Check if provided zipcode is valid
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--There are 11 students for zipcode 07024
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--Done...
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--b) Auf Basis der Ausgabe von a. welches Exception-Handling muss hinzugefügt werden?
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-- EXCEPTION
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-- WHEN NO_DATA_FOUND THEN
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-- DBMS_OUTPUT.PUT_LINE('No valid zipcode found: ' || v_zip);
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-- WHEN OTHERS THEN
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-- DBMS_OUTPUT.PUT_LINE('An error has occurred: ' || SQLERRM);
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-- Aufgabe 7.6
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DECLARE
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v_instructor_id NUMBER := &sv_instructor_id;
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v_tot_sections NUMBER;
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v_name VARCHAR2(30);
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e_too_many_sections EXCEPTION;
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BEGIN
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SELECT COUNT(*)
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INTO v_tot_sections
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FROM section
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WHERE instructor_id = v_instructor_id;
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IF v_tot_sections >= 10 THEN
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RAISE e_too_many_sections;
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ELSE
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SELECT RTRIM(first_name)||' '||RTRIM(last_name)
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INTO v_name
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FROM instructor
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WHERE instructor_id = v_instructor_id;
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DBMS_OUTPUT.PUT_LINE ('Instructor, '||v_name||', teaches '||
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v_tot_sections||' sections');
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END IF;
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EXCEPTION
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WHEN e_too_many_sections THEN
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DBMS_OUTPUT.PUT_LINE ('This instructor teaches too much');
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END;
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/
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--a) Was wird ausgegeben, wenn das Skript für 101 und 102 ausgeführt wird?
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-- 101: This instructor teaches too much
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-- 102: Instructor, John Smith, teaches 2 sections
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--b) Welche Anweisung löst die User-Defined Exception aus?
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-- RAISE e_too_many_sections;
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--c) Ändere das Skript so, dass auch der Nachname in der Fehlermeldung ausgegeben wird.
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DECLARE
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v_instructor_id NUMBER := &sv_instructor_id;
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v_tot_sections NUMBER;
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v_name VARCHAR2(30);
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e_too_many_sections EXCEPTION;
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BEGIN
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SELECT COUNT(*)
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INTO v_tot_sections
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FROM section
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WHERE instructor_id = v_instructor_id;
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SELECT RTRIM(first_name)||' '||RTRIM(last_name)
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INTO v_name
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FROM instructor
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WHERE instructor_id = v_instructor_id;
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IF v_tot_sections >= 10 THEN
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RAISE e_too_many_sections;
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ELSE
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SELECT RTRIM(first_name)||' '||RTRIM(last_name)
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INTO v_name
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FROM instructor
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WHERE instructor_id = v_instructor_id;
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DBMS_OUTPUT.PUT_LINE ('Instructor, '||v_name||', teaches '||
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v_tot_sections||' sections');
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END IF;
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EXCEPTION
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WHEN e_too_many_sections THEN
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DBMS_OUTPUT.PUT_LINE ('This instructor ' || v_name || ' teaches too much');
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END;
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/
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-- Aufgabe 7.7
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DECLARE
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v_my_name VARCHAR2(15) := 'ELENA SILVESTROVA';
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BEGIN
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DBMS_OUTPUT.PUT_LINE ('My name is '||v_my_name);
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DECLARE
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v_your_name VARCHAR2(15);
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BEGIN
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v_your_name := '&sv_your_name';
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DBMS_OUTPUT.PUT_LINE ('Your name is '||v_your_name);
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the inner block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END;
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the outer block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END;
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/
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--a) Da der default wert für v_my_name zu lang ist, wird eine string buffer exception geworfen
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--b) Nein es wird der Rest nicht ausgeführt
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--c)
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DECLARE
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BEGIN
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DECLARE
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v_my_name VARCHAR2(15) := 'ELENA SILVESTROVA';
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BEGIN
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DBMS_OUTPUT.PUT_LINE ('My name is '||v_my_name);
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DECLARE
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v_your_name VARCHAR2(15);
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BEGIN
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v_your_name := '&sv_your_name';
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DBMS_OUTPUT.PUT_LINE ('Your name is '||v_your_name);
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the inner block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END;
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the outer block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END;
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EXCEPTION
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WHEN others THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the outer block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END;
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/
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-- Aufgabe 7.8)
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DECLARE
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v_section_id NUMBER := &sv_section_id;
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v_total_students NUMBER;
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e_too_many_students EXCEPTION;
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BEGIN
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SELECT COUNT(*)
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INTO v_total_students
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FROM enrollment
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WHERE section_id = v_section_id;
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IF v_total_students >= 10 THEN
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RAISE e_too_many_students;
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ELSE
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DBMS_OUTPUT.PUT_LINE('Number of students: ' || v_total_students);
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END IF;
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EXCEPTION
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WHEN e_too_many_students THEN
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DBMS_OUTPUT.PUT_LINE('Too many students in section ' || v_section_id);
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WHEN OTHERS THEN
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DBMS_OUTPUT.PUT_LINE('An error has occurred.');
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END;
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/
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-- Aufgabe 7.9)
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DECLARE
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BEGIN
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DECLARE
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v_my_name VARCHAR2(15) := 'ELENA SILVESTROVA';
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BEGIN
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DBMS_OUTPUT.PUT_LINE ('My name is '||v_my_name);
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DECLARE
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v_your_name VARCHAR2(15);
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BEGIN
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v_your_name := '&sv_your_name';
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DBMS_OUTPUT.PUT_LINE ('Your name is '||v_your_name);
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the inner block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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RAISE; -- Reraise the exception to be handled by the outer block
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END;
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the outer inner block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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RAISE;
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END;
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EXCEPTION
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WHEN VALUE_ERROR THEN
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DBMS_OUTPUT.PUT_LINE ('Error in the outer outer block');
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DBMS_OUTPUT.PUT_LINE ('This name is too long');
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END; |