Distributed Database Applications COSC 5050 Week One

Jiangping Wang Webster UniversityDistributed Database Applications Outline Introduction Course overview Oracle client environment Data dictionary Language fundamentals Program control

Jiangping Wang Webster UniversityDistributed Database Applications Introduction Oracle database PL/SQL Accessing Oracle server Database objects DDL and DML statements

Jiangping Wang Webster UniversityDistributed Database Applications PL/SQL Many Oracle applications are built using client-server architecture The Oracle database resides on the server PL/SQL is like any other programming language PL/SQL is not a stand-alone programming language PL/SQL is a part of the Oracle RDBMS

Jiangping Wang Webster UniversityDistributed Database Applications PL/SQL Highly structured, readable, accessible language Standard and portable language Embedded language High-performance, highly integrated database language

Jiangping Wang Webster UniversityDistributed Database Applications Advantages of PL/SQL

Jiangping Wang Webster UniversityDistributed Database Applications SQL Example The semicolon terminates CREATE, INSERT, SELECT, and DROP statements CREATE TABLE STUDENT ( FIRST_NAME VARCHAR2(20), LAST_NAME VARCHAR2(20) ); INSERT INTO STUDENT VALUES (‘JOHN’, ‘LUCKY’); SELECT FIRST_NAME, LAST_NAME FROM STUDENT; DROP TABLE STUDENT;

Jiangping Wang Webster UniversityDistributed Database Applications PL/SQL Example Page 7, 8, 9, 39 examples When Oracle reads a PL/SQL block, a semicolon marks the end of the individual statement within the block It is not a block terminator! The “/” executes the PL/SQL block

Jiangping Wang Webster UniversityDistributed Database Applications Integration with SQL DECLARE l_book_count INTEGER; BEGIN SELECT COUNT(*) INTO l_book_count FROM books WHERE author LIKE '%Feuerstein, Steven%'; DBMS_OUTPUT.PUT_LINE( 'Steven have written (or co-written) ' || l_book_count || ' books.'); UPDATE books SET author = REPLACE (author, 'Steven', 'Stephen') WHERE author LIKE '%Feuerstein, Steven%'; END;

Jiangping Wang Webster UniversityDistributed Database Applications Control and Conditional Logic CREATE OR REPLACE PROCEDURE pay_out_balance( account_id_in IN accounts.id%TYPE) IS l_balance_remaining NUMBER; BEGIN LOOP l_balance_remaining := account_balance (account_id_in); IF l_balance_remaining < 1000 THEN EXIT; ELSE apply_balance ( accont_id_in, l_balance_remaining); END IF; END LOOP; END pay_out_balance;

Jiangping Wang Webster UniversityDistributed Database Applications When Things Go Wrong CREATE OR REPLACE PROCEDURE check_account(account_id_in IN accounts.id%TYPE) IS l_balance_remainingNUMBER; l_balance_below_minimum EXCEPTION; l_account_nameaccounts.name%TYPE; BEGIN SELECT name INTO l_account_name FROM accounts WHERE id = account_id_in; l_balance_remaining := account_balance (account_id_in); DBMS_OUTPUT.put_line ( 'Balance for ' || l_account_name || ' = ' || l_balance_remaining); IF l_balance_remaining < 1000 THEN RAISE l_balance_below_minimum; END IF; EXCEPTION WHEN NO_DATA_FOUND THEN log_error (...); WHEN l_balance_below_minimum THEN log_error (...); RAISE; END;

Jiangping Wang Webster UniversityDistributed Database Applications Creating a Stored Program CREATE OR REPLACE FUNCTION wordcount (str IN VARCHAR2) RETURN PLS_INTEGER AS words PLS_INTEGER := 0; len PLS_INTEGER := NVL(LENGTH(str),0); inside_a_word BOOLEAN; BEGIN FOR i IN 1..len + 1 LOOP IF ASCII(SUBSTR(str, i, 1)) len THEN IF inside_a_word THEN words := words + 1; inside_a_word := FALSE; END IF; ELSE inside_a_word := TRUE; END IF; END LOOP; RETURN words; END;

Jiangping Wang Webster UniversityDistributed Database Applications Executing, Showing, and Dropping a Stored Program BEGIN DBMS_OUTPUT.PUT_LINE( 'There are ' || wordcount(CHR(9)) || ' words in a tab'); END; SELECT * FROM USER_OBJECTS; DESC wordcount SELECT TEXT FROM USER_SOURCE WHERE NAME = 'WORDCOUNT'; DROP FUNCTION wordcount;

Jiangping Wang Webster UniversityDistributed Database Applications Access Oracle Oracle server (service and host name) cronus, icarus.webster.edu Oracle client Oracle 11g client download SQL*Plus SQL Developer Application Express (APEX) Workspace Your login and password

Jiangping Wang Webster UniversityDistributed Database Applications Oracle SQL*Plus

Jiangping Wang Webster UniversityDistributed Database Applications Oracle SQL Developer

Jiangping Wang Webster UniversityDistributed Database Applications Oracle APEX

Jiangping Wang Webster UniversityDistributed Database Applications Data Dictionary USER_ ALL_ DBA_ select view_name from all_views where view_name like 'USER%';

Jiangping Wang Webster UniversityDistributed Database Applications Language Fundamentals PL/SQL block structure Modularization Scope Anonymous blocks Named blocks Procedures Functions Scope and visibility

Jiangping Wang Webster UniversityDistributed Database Applications PL/SQL Block Structure Header Declaration section Execution section Exception section PROCEDURE get_happy (ename_in IN VARCHAR2) IS hiredata DATE; BEGIN hiredate := SYSDATE – 2; INSERT INTO employee (emp_name, hiredate) VALUES (ename_in, hiredate); EXCEPTION WHEN dup_val_in_index THEN DBMS_OUTPUT.PUT_LINE (‘Cannot insert.’); END;

Jiangping Wang No header Begin with either DECLARE or BEGIN Cannot be called Webster UniversityDistributed Database Applications Anonymous Blocks BEGIN DBMS_OUTPUT.PUT_LINE (SYSDATE); END; DECLARE l_right_now DATE := SYSDATE; BEGIN DBMS_OUTPUT.PUT_LINE (l_right_now); END;

Jiangping Wang Procedures Functions Webster UniversityDistributed Database Applications Named Blocks procedure Add_employee (ssninvarchar2, fnameinvarchar2, lnameinvarchar2, dept_numinnumber, codeinnumber, sup_ssninvarchar2) is begin insert into employee values (ssn, fname, lname, dept_num, code, sup_ssn); end; -- Add_employee

Jiangping Wang Webster UniversityDistributed Database Applications Named Blocks function get_department(ssn_in in employee.ssn%type) return department.dept_name%type is l_dept_name department.dept_name%type; begin select dept_name into l_dept_name from department inner join employee on employee.dept_num = department.dept_num where ssn = ssn_in; dbms_output.put_line('department name: ' || l_dept_name); return l_dept_name; exception when no_data_found then dbms_output.put_line( 'no such employee or not in any department!'); return null; end;

Jiangping Wang Named Blocks in DB2 Webster UniversityDistributed Database Applications CREATE PROCEDURE sum( IN p_a INTEGER, IN p_b INTEGER, OUT p_s INTEGER) LANGUAGE SQL BEGIN SET p_s = p_a + p_b; END; CALL sum(100,200,?);

Jiangping Wang Webster UniversityDistributed Database Applications Language Fundamentals PL/SQL character set Case-insensitive language Identifiers Up to 30 characters in length Must start with a letter Can include $, _, and # Cannot contain spaces PL/SQL keywords Comments Single-line comments using “--” Multi-line comments using /* … */

Jiangping Wang Webster UniversityDistributed Database Applications PL/SQL Character Set TypeCharacters LettersA-Z, a-z Digits0-9 Symbols~ # $ % * ( ) _ - + = | : ; " ',. ? / ^ WhitespaceTab, space, newline, carriage return

Jiangping Wang Distributed Database Applications Program Control IF statements CASE LOOP WHILE loop Cursor loop

Jiangping Wang Distributed Database Applications IF Statement IF salary > THEN give_bonus (employee_id, 500); END IF; IF salary <= THEN give_bonus (employee_id, 0); ELSE give_bonus (employee_id, 500); END IF; declare salary number := 40000; begin IF salary > THEN dbms_output.put_line('Salary is greater than 40000'); ELSE dbms_output.put_line('Salary is not greater than 40000'); END IF; end; /

Jiangping Wang Distributed Database Applications IF Statement declare salary number := &salary; begin IF salary BETWEEN AND THEN dbms_output.put_line('Give bonus 1500.'); ELSIF salary BETWEEN AND THEN dbms_output.put_line('Give bonus 1000.'); ELSIF salary > THEN dbms_output.put_line('Give bonus 500.'); ELSE dbms_output.put_line('Give bonus 0.'); END IF; end; /

Jiangping Wang Distributed Database Applications CASE Statement declare salary_level number := &salary; begin case salary_level when 1 then dbms_output.put_line('give bonus 1500.'); when 2 then dbms_output.put_line('give bonus 1000.'); when 3 then dbms_output.put_line('give bonus 500.'); else dbms_output.put_line('give bonus 0.'); end case; end; / Simple CASE statement

Jiangping Wang Searched CASE statement Distributed Database Applications CASE Statement declare salary number := &salary; begin case when salary between and then dbms_output.put_line('give bonus 1500.'); when salary between and then dbms_output.put_line('give bonus 1000.'); when salary > then dbms_output.put_line('give bonus 500.'); else dbms_output.put_line('give bonus 0.'); end case; end; /

Jiangping Wang CASE expression Distributed Database Applications CASE Statement declare salary number := &salary; bonus_amount number; begin bonus_amount := case when salary BETWEEN AND THEN 1500 when salary BETWEEN AND THEN 1000 when salary > THEN 500 else 0 end; dbms_output.put_line( 'Give bonus ' || bonus_amount || '.'); end; /

Jiangping Wang Distributed Database Applications Loop Statement Simple loop FOR loop WHILE loop Cursor FOR loop

Jiangping Wang Distributed Database Applications Simple Loop PROCEDURE set_all_ranks (max_rank_in IN INTEGER) IS ranking_level NUMBER (3) := 1; BEGIN LOOP EXIT WHEN ranking_level > max_rank_in; set_rank (ranking_level); ranking_level := ranking_level + 1; END LOOP; END set_all_ranks; Use EXIT or EXIT WHEN to exit loop

Jiangping Wang Distributed Database Applications For Loop PROCEDURE set_all_ranks (max_rank_in IN INTEGER) IS ranking_level NUMBER (3) := 1; BEGIN FOR ranking_level IN 1.. max_rank_in LOOP set_rank (ranking_level); END LOOP; END set_all_ranks; Reverse loop: FOR counter IN REVERSE 1.. max LOOP … END LOOP;

Jiangping Wang Distributed Database Applications WHILE Loop PROCEDURE set_all_ranks (max_rank_in IN INTEGER) IS ranking_level NUMBER (3) := 1; BEGIN WHILE ranking_level <= max_rank_in LOOP set_rank (ranking_level); ranking_level := ranking_level + 1; END LOOP; END set_all_ranks;

Jiangping Wang Distributed Database Applications Cursor FOR Loop Cursor with simple loop DECLARE CURSOR name_cur IS SELECT lname, fname FROM employee WHERE ssn like '8%'; name_rec name_cur%ROWTYPE; BEGIN OPEN name_cur; LOOP FETCH name_cur INTO name_rec; EXIT WHEN name_cur%NOTFOUND; DBMS_OUTPUT.PUT_LINE( name_rec.fname || ' ' || name_rec.lname); END LOOP; CLOSE name_cur; END; /

Jiangping Wang Distributed Database Applications Cursor FOR Loop Cursor with simple loop DECLARE CURSOR occupancy_cur IS SELECT pet_id, room_number FROM occupancy WHERE occupied_dt = TRUNC(SYSDATE); occupancy_rec occupancy_cur%ROWTYPE; BEGIN OPEN occupancy_cur; LOOP FETCH occupancy_cur INTO occupancy_rec; EXIT WHEN occupancy_cur%NOTFOUND; update_bill (occupancy_rec.pet_id, occupancy_rec.room_number); END LOOP; CLOSE occupancy_cur; END;

Jiangping Wang Distributed Database Applications Cursor FOR Loop Cursor For loop DECLARE CURSOR occupancy_cur IS SELECT pet_id, room_number FROM occupancy WHERE occupied_dt = TRUNC(SYSDATE); BEGIN FOR occupancy_rec IN occupancy_cur LOOP update_bill (occupancy_rec.pet_id, occupancy_rec.room_number); END LOOP; END;

Jiangping Wang Distributed Database Applications Cursor FOR Loop Cursor FOR loop DECLARE CURSOR name_cur IS SELECT lname, fname FROM employee WHERE ssn like '8%'; BEGIN FOR name_rec IN name_cur LOOP DBMS_OUTPUT.PUT_LINE( name_rec.fname || ' ' || name_rec.lname); END LOOP; END; /

Jiangping Wang Webster UniversityDistributed Database Applications Homework Given the table layout, write the SQL to create the table Create a script file to load database table Create an anonymous PL/SQL block to retrieve data from above database table Create a simple procedure in your DB2 Company schema to retrieve employee data Project proposal