DB2 SQL Workshop for Experienced Users (Course Code CF13)

Transcription

1 DB2 SQL Workshop for Experienced Users (Course Code CF13) ERC4.1 IBM Learning Services Worldwide Certified Material

2 Publishing Information This publication has been produced using BookMaster (Program Number ), the Document Composition Facility (Program Number 5748-XX9), and Freelance for Windows. It was printed on the IBM 3820 Page Printer. Trademarks IBM is a registered trademark of International Business Machines Corporation. The following are trademarks International Business Machines Corporation in the United States, or other countries, or both: AIX AS/400 BookMaster DataJoiner DB2 DB2 Universal Database OS/2 OS/390 OS/400 QMF SQL/DS Freelance Graphics and Lotus are trademarks of Lotus Development Corporation in the United States, or other countries, or both. Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both. Microsoft, Windows, Windows NT, and the Windows logo are trademarks of Microsoft Corporation in the United States, other countries, or both. Intel is a registered trademark of Intel Corporation in the United States, other countries, or both. UNIX is a registered trademark in the United States and other countries licensed exclusively through The Open Group. Linux is a trademark of Linus Torvalds. Other company, product, and service names may be trademarks or service marks of others. January, 2001 The information contained in this document has not been submitted to any formal IBM test and is distributed on an as is basis without any warranty either express or implied. The use of this information or the implementation of any of these techniques is a customer responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. While each item may have been reviewed by IBM for accuracy in a specific situation, there is no guarantee that the same or similar results will result elsewhere. Customers attempting to adapt these techniques to their own environments do so at their own risk. The original repository material for this course has been certified as being Year 2000 compliant. Copyright International Business Machines Corporation 1998, All rights reserved. This document may not be reproduced in whole or in part Note to U.S. Government Users Documentation related to restricted rights Use, duplication or disclosure is subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp.

3 Contents Exercises Description v Table Descriptions xiii Table Content xv Exercises Exercise 1. SQL Basics Review, CUBE AND ROLLUP Exercise 2. Create Objects Exercise 3. Joins Exercise 4. CASE and CAST Exercise 5. Subqueries Exercise 6. Scalar Functions Exercise 7. Table Expressions and Recursive SQL Exercise 8. Performance and UDT/UDF Copyright IBM Corp. 1998, 2001 Contents iii

4 iv DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

5 Exercises Description Be sure to read the General Information section and the description of the lab tables before attempting the exercises. Feel free to consult with the instructor if you need a hint or encounter difficulties while you are formulating the query. Expected Results repeats the problem and shows the results that you should get if you run the query. In most cases, the complete result is shown. In cases where the result set is too large, an ellipsis (...) is shown to indicate that there are additional rows in the result. In these cases, the correct number of rows for the result set is shown so that you can be sure that you got the right result. Solutions contains the correct query that solves the problem. Remember that sometimes there can be several correct answers. Your solution may be different than the one shown in the document. If you have any doubts about whether your solution is correct or if it is as good as the given solution from a performance point of view, please consult your instructor. General Information This lab guide provides the information necessary to complete the required and optional labs for the IBM DB2 SQL Workshop for Experienced Users course. In countries that provide several query tools for each environment, this lab guide will be supplemented by additional documentation that describes the basics of each query tool. You can do the exercises for this course in OS/390 or in a Workstation environment. Depending on where you are taking the course, these Workstation platforms may be available for your use: OS/2, AIX, Windows 95/98 or Windows NT. Be sure to read the instructions for the operating system you chose before attempting the exercises. All of the workstation platforms use the same instructions. You will be able to use any of the query tools that we have installed on each operating system. Please note that the emphasis of this course is on teaching you SQL, not how to use the tools. Therefore, you will only see the basics of using the tool in this course. If you want more information about these tools, ask the instructor for recommendations on the best manuals to read or courses to take for this purpose. Copyright IBM Corp. 1998, 2001 Exercises Description v

6 You do not need to save your solutions or show them to the instructor but feel free to do so if you like. Full solutions are provided for every question but if you wish to save your own solutions to diskette or print them, ask your instructor when you begin the first exercise. In some cases, diskettes or printers may not be available. vi DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

7 General Information for OS/390 Users There are many different query tools that work with DB2 for OS/390, including SPUFI, QMF, and others. You can use any tool installed to do the labs. The following query tools are available for this course: The instructor will tell you how to logon to the OS/390 system and what specific user ID and password to use. In addition, you will probably be given a team number: this number will be used occasionally during the exercises so that you can distinguish your files or objects from those of other students. Your logon ID is. Your password is. Your team number is. The instructor will give you brief verbal or written instructions on how to use the tool you choose so that you will have enough information to get started. If you want to know more about a tool, for example how to save a query, be sure to ask the instructor. You will need a partitioned dataset in order to complete the exercises. This dataset already exists. The dataset name is. Each of the tables described in the Table Relationships section of this document already exists and has the same qualifier. The qualifier is. When you refer to these tables in your SQL, you will need to prefix the table names with the qualifier identified above. For example, if you want to display the complete contents of the EMPLOYEE table, enter the following, substituting the qualifier you were given: SELECT * FROM qualifier.employee Note: Using member CRTAB to create table TESTEMP, if the table has not been provided in advance. You may need to add an IN clause to your CREATE TABLE statements that identifies where the table is being created. The IN clause you need to add is: IN. Copyright IBM Corp. 1998, 2001 Exercises Description vii

8 When you are using the TESTEMP table, you will have to omit the qualifier or use your logon ID as qualifier. For example, if you are trying to read the TESTEMP table, you will have to write: SELECT * FROM TESTEMP or SELECT * FROM logon ID.TESTEMP You do not have to save your SQL but if you want to save it, you may put it in your partitioned dataset. viii DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

9 General Information for DB2 UDB on UNIX, Windows and OS/2 Users There are many different query tools that work with DB2 on the workstation platforms, including Command Center, CLP, and others. You can use any tool installed to do the labs. The following query tools are available for this course: Students doing the exercises on workstation platforms do not need a team number. Each workstation student has a complete standalone environment and will not share any files or tables with other students. Each student will have to sign on with the following information: USERID is PASSWORD is The instructor will give you brief verbal or written instructions on how to use the tool you choose so that you have enough information to get started. If you want to know more about a tool, for example how to save a query, be sure to ask the instructor. A database named sample has already been created for you. To connect in a single-user environment, enter the following at a command prompt: db2 connect to sample To connect in a client/server environment, enter the following at a command prompt, substituting the userid and password you were assigned: db2 connect to sample user userid using password Each of the tables described in the Table Relationships section of this document already exists and has the same qualifier. The qualifier is. When you refer to these tables in your SQL, you will need to prefix the table names with the qualifier identified above. For example, if you want to display the complete contents of the EMPLOYEE table, enter the following, substituting the qualifier you were given: SELECT * FROM qualifier.employee Copyright IBM Corp. 1998, 2001 Exercises Description ix

10 Note: Using member CRTAB to create table TESTEMP, if the table has not been provided in advance. Using the following command to create table TESTEMP: DB2 -tvf CRTAB In cases where you are using your TESTEMP table you need to omit the qualifier or use your logon ID as qualifier. For example, if you are trying to read the TESTEMP table, you will need to write: SELECT * FROM TESTEMP or SELECT * FROM logon ID.TESTEMP If you choose to do the labs in CLP, you may create your SQL in the \CF13 directory. x DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

11 Figure 0-1. Table Relationships (CF13X010) Notes:: This diagram illustrates the relationships between the tables used in the exercises for this course. The lines show the connection between the tables. Copyright IBM Corp. 1998, 2001 Exercises Description xi

12 xii DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

13 Table Descriptions The tables are described in hierarchical order, as shown in the Table Relationships on the previous page. DEPARTMENT There is one row in the DEPARTMENT table for each department in the company. Column Name Meaning Data Type NULLS allowed DEPTNO Department Number CHAR(3) N DEPTNAME Department Name VARCHAR(36) N MGRNO Employee Number of the Responsible CHAR(6) Y Manager ADMRDEPT Department Number of the CHAR(3) N Department to which the Department reports LOCATION Location Number CHAR(5) Y EMPLOYEE There is one row in the EMPLOYEE table for each of the employees in the company. Column Name Meaning Data Type NULLS allowed EMPNO Employee Number CHAR(6) N FIRSTNME First Name VARCHAR(20) N MIDINIT Middle Initial CHAR(1) N LASTNAME Last Name VARCHAR(15) N WORKDEPT Department in which the Employee CHAR(3) Y Works PHONENO Phone Number CHAR(4) Y HIREDATE Date of Hire DATE Y JOB Job CHAR(8) Y EDLEVEL Number of Years of Formal Education SMALLINT Y SEX Sex (M male, F female) CHAR(1) Y BIRTHDATE Date of Birth DATE Y SALARY Yearly Salary DECIMAL(9, 2) Y BONUS Yearly Bonus DECIMAL(9, 2) Y COMM Yearly Commission DECIMAL(9, 2) Y Copyright IBM Corp. 1998, 2001 Table Descriptions xiii

14 PROJECT There is one row in the PROJECT table for each project. Column Name Meaning Data Type NULLS allowed PROJNO Project Number CHAR(6) N PROJNAME Project Name VARCHAR(24) N DEPTNO Responsible Department CHAR(3) N RESPEMP Employee Number of the Responsible CHAR(6) N Employee PRSTAFF Estimated Mean Staffing DECIMAL(5, 2) Y PRSTDATE Estimated Start Date DATE Y PRENDATE Estimated End Date DATE Y MAJPROJ Major Project for a Subproject CHAR(6) Y EMP_ACT There are many rows in the EMP_ACT table for any employee or any project. Column Name Meaning Data Type NULLS allowed EMPNO Employee Number of Employee CHAR(6) N Performing the Activity PROJNO Project Number CHAR(6) N ACTNO Activity Number SMALLINT N EMPTIME Proportion of Employee's Time Spent DECIMAL(5, 2) Y on Project EMSTDATE Date Activity Starts DATE Y EMENDATE Date Activity Ends DATE Y xiv DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

15 Table Content DEPARTMENT Table DEPTNO DEPTNAME MGRNO ADMRDEPT LOCATION A00 SPIFFY COMPUTER SERVICE DIV A00 B01 PLANNING A00 C01 INFORMATION CENTER A00 D01 DEVELOPMENT CENTER - A00 D11 MANUFACTURING SYSTEMS D01 D21 ADMINISTRATION SYSTEMS D01 E01 SUPPORT SERVICES A00 E11 OPERATIONS E01 E21 SOFTWARE SUPPORT E01 Copyright IBM Corp. 1998, 2001 Table Content xv

16 EMPLOYEE Table EMPNO FIRSTNME MIDINIT LASTNAME WORKDEPT PHONENO HIREDATE CHRISTINE I HAAS A MICHAEL L THOMPSON B SALLY A KWAN C JOHN B GEYER E IRVING F STERN D EVA D PULASKI D EILEEN W HENDERSON E THEODORE Q SPENSER E VINCENZO G LUCCHESI A SEAN O'CONNELL A DOLORES M QUINTANA C HEATHER A NICHOLLS C BRUCE ADAMSON D ELIZABETH R PIANKA D MASATOSHI J YOSHIMURA D MARILYN S SCOUTTEN D JAMES H WALKER D DAVID BROWN D WILLIAM T JONES D JENNIFER K LUTZ D JAMES J JEFFERSON D SALVATORE M MARINO D DANIEL S SMITH D SYBIL V JOHNSON D MARIA L PEREZ D ETHEL R SCHNEIDER E JOHN R PARKER E PHILIP X SMITH E MAUDE F SETRIGHT E RAMLAL V MEHTA E WING LEE E JASON R GOUNOT E xvi DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

17 EMPLOYEE Table (Cont) JOB EDLEVEL SEX BIRTHDATE SALARY BONUS COMM PRES 18 F MANAGER 18 M MANAGER 20 F MANAGER 16 M MANAGER 16 M MANAGER 16 F MANAGER 16 F MANAGER 14 M SALESREP 19 M CLERK 14 M ANALYST 16 F ANALYST 18 F DESIGNER 16 M DESIGNER 17 F DESIGNER 16 M DESIGNER 17 F DESIGNER 16 M DESIGNER 16 M DESIGNER 17 M DESIGNER 18 F CLERK 14 M CLERK 17 M CLERK 15 M CLERK 16 F CLERK 15 F OPERATOR 17 F OPERATOR 12 M OPERATOR 14 M OPERATOR 12 F FIELDREP 16 M FIELDREP 14 M FIELDREP 16 M Copyright IBM Corp. 1998, 2001 Table Content xvii

18 PROJECT Table DEPT PR PROJNO PROJNAME NO RESPEMP STAFF PRSTDATE PRENDATE MAJPROJ AD3100 ADMIN SERVICES D AD3110 GENERAL AD SYSTEMS D AD3100 AD3111 PAYROLL PROGRAMMING D AD3110 AD3112 PERSONNEL PROGRAMMG D AD3110 AD3113 ACCOUNT.PROGRAMMING D AD3110 IF1000 QUERY SERVICES C IF2000 USER EDUCATION C MA2100 WELD LINE AUTOMATION D MA2110 W L PROGRAMMING D MA2100 MA2111 W L PROGRAM DESIGN D MA2110 MA2112 W L ROBOT DESIGN D MA2110 MA2113 W L PROD CONT PROGS D MA2110 OP1000 OPERATION SUPPORT E OP1010 OPERATION E OP1000 OP2000 GEN SYSTEMS SERVICES E OP2010 SYSTEMS SUPPORT E OP2000 OP2011 SCP SYSTEMS SUPPORT E OP2010 OP2012 APPLICATIONS SUPPORT E OP2010 OP2013 DB/DC SUPPORT E OP2010 PL2100 WELD LINE PLANNING B MA2100 xviii DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

19 EMP_ACT Table EMPNO PROJNO ACTNO EMPTIME EMSTDATE EMENDATE AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD IF IF IF IF Copyright IBM Corp. 1998, 2001 Table Content xix

20 EMP_ACT Table (Cont) EMPNO PROJNO ACTNO EMPTIME EMSTDATE EMENDATE IF IF IF IF IF MA MA MA MA MA MA MA MA MA MA MA MA MA MA MA MA MA OP OP OP OP OP OP OP OP OP OP OP OP OP OP PL xx DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

21 CARS Table The CARS table is to use in unit 7 (recursive SQL). LEVEL ASSEMBLY COMPONENT QUANTITY HONDA ACCORD ENGINE COMPARTMENT 1 1 HONDA ACCORD PASSENGER COMPARTMENT 1 2 ENGINE COMPARTMENT ENGINE 1 2 ENGINE COMPARTMENT IGNITION SYSTEM 1 2 PASSENGER COMPARTMENT SEAT GROUP 3 2 PASSENGER COMPARTMENT DASHBOARD 1 2 PASSENGER COMPARTMENT TRUNK 1 3 ENGINE CAMSHAFT 1 3 ENGINE CRANKSHAFT 1 3 ENGINE PISTON 4 3 ENGINE CONNECTING ROD 4 3 SEAT GROUP FRONT SEAT ASSEMBLY 2 3 SEAT GROUP REAR SEAT ASSEMBLY 1 3 DASHBOARD VENT 4 3 DASHBOARD STEREO SYSTEM 1 3 DASHBOARD GAUGE CLUSTER 1 3 DASHBOARD CONTROL CLUSTER 1 3 TRUNK TOOL KIT 1 4 STEREO SYSTEM RADIO 1 4 STEREO SYSTEM CD PLAYER 1 4 GAUGE CLUSTER SPEEDOMETER 1 4 GAUGE CLUSTER ODOMETER 1 4 CONTROL CLUSTER FOG LAMP CONTROL 1 4 CONTROL CLUSTER FOUR WAY FLASHER CONTROL 1 4 CONTROL CLUSTER TURN SIGNAL CONTROL 1 4 FRONT SEAT ASSEMBLY FRONT SEAT 1 4 FRONT SEAT ASSEMBLY LAP/SHOULDER BELT 1 4 REAR SEAT ASSEMBLY REAR SEAT 1 4 REAR SEAT ASSEMBLY LAP/SHOULDER BELT 3 4 REAR SEAT ASSEMBLY SHOULDER BELT 3 Copyright IBM Corp. 1998, 2001 Table Content xxi

22 TESTEMP Table The TESTEMP table is to use in unit 2 (views). EMPNO LASTNAME WORKDEPT HIREDATE SALARY BONUS SMITH C HAAS A THOMPSON B KWAN C GEYER E xxii DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

23 Content of VIEWS The listed views have to be used for the exercises in unit 3. Data types are listed in the table description. VEMPLOYEE View EMPNO LASTNAME SALARY WORKDEPT HAAS A KWAN C O'CONNELL A QUINTANA C NICHOLLS C01 VDEPARTMENT View DEPTNO DEPTNAME MGRNO A00 SPIFFY COMPUTER SERVICE DIV C01 INFORMATION CENTER D01 DEVELOPMENT CENTER VPROJECT View PROJNO PROJNAME DEPTNO RESPEMP AD3100 ADMIN SERVICES D IF1000 QUERY SERVICES C IF2000 USER EDUCATION C Copyright IBM Corp. 1998, 2001 Table Content xxiii

24 Each exercise in this course is divided into sections as described below. Select the section that best fits your method of performing labs. You may elect to use a combination of these sections as appropriate. Exercise Instructions This section contains what it is you are to accomplish. There are no definitive details on how to perform the tasks. You can work through the exercises based on what you have learned in the unit presentation, as well as the unit Student Notebook, your past experience and some intuition. Exercise Instructions With Hints This section is an exact duplicate of the Exercise Instructions section except that in addition, specific details and/or hints are provided to help step you through the exercise. A combination of using the Instructions section along with Instructions With Hints section can make for a rewarding combination providing you with no hints when you don't want them and hints when you need them. xxiv DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

25 Exercise 1. SQL Basics Review, CUBE AND ROLLUP What This Exercise Is About This exercise provides an opportunity to review some basic topics What You Should Be Able to Do At the end of the lab, you should be able to: Code SELECT statements with multiple conditions Use the GROUP BY clause Use column functions Use the new super groups features, CUBE & ROLLUP Introduction See the data model at the start of this Exercise Guide to get the column names and descriptions for each table. Required Materials Student handout SQL Reference Copyright IBM Corp. 1998, 2001 Exercise 1. SQL Basics Review, CUBE & ROLLUP 1-1

26 Exercise Instructions Problem 1 Problem 2 Problem 3 Problem 4 Ron is the SQL specialist in the department. Joe is a colleague of Ron and does not have SQL knowledge. Joe asked Ron for help to solve the following problems. Note: See the data model at the beginning of this exercise guide for descriptions of the tables used in the labs and for their column names. Joe's manager wants information about employees which match the following criteria: Their yearly salary is between and They work in departments D11 or D21. List the employee number, last name, yearly salary, and department number of the appropriate employees. Now, Joe's manager wants information about the yearly salary. He wants to know the minimum, the maximum, and average yearly salary of all employees with an education level of 16. He also wants to know how many employees have this education level. Joe's manager is interested in some additional salary information. This time, he wants information for every department that appears in the EMPLOYEE table, provided that the department has more than five employees. The report needs to show the department number, the minimum, maximum, and average yearly salary, and the number of employees who work in the department. Joe's manager wants information about employees grouped by department, grouped by sex and in addition by the combination of department and sex. List only those who work in a department which start with the letter D. List the department, the sex, sum of the salaries, minimum salary and maximum salary. Note, the solution of this problem can only be used on DB2 UDB for UNIX, Windows and OS/2. END OF LAB 1-2 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

27 Exercise Instructions With Hints (Expected Results) Problem 1 Joe's manager wants information about employees which match the following criteria: Their yearly salary is between and They work in departments D11 or D21. Result Problem 2 Result Problem 3 Result Problem 4 List the employee number, last name, yearly salary, and department number of the appropriate employees. EMPNO LASTNAME SALARY WORKDEPT PIANKA D JEFFERSON D21 Now, Joe's manager wants information about the yearly salary. He wants to know the minimum, the maximum, and average yearly salary of all employees with an education level of 16. He also wants to know how many employees have this education level. MIN MAX AVG COUNT Joe's manager is interested in some additional salary information. This time, he wants information for every department that appears in the EMPLOYEE table, provided that the department has more than five employees. The report needs to show the department number, the minimum, maximum, and average yearly salary, and the number of employees who work in the department. WORKDEPT MIN MAX AVG COUNT D D Joe's manager wants information about employees grouped by department, grouped by sex and in addition by the combination of department and sex. List only those who work in a department which start with the letter D. List the department, the sex, sum of the salaries, minimum salary and maximum salary. Copyright IBM Corp. 1998, 2001 Exercise 1. SQL Basics Review, CUBE & ROLLUP 1-3

28 Result Note, the solution of this problem can only be used on DB2 UDB for UNIX, Windows and OS/2. WORKDEPT SEX MIN MAX SUM D D F M D11 F D21 F D11 M D21 M record(s) selected. END OF LAB (with hints) 1-4 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

29 Solution Problem 1 Problem 2 Problem 3 Problem 4 SELECT EMPNO, LASTNAME, SALARY, WORKDEPT FROM EMPLOYEE WHERE WORKDEPT IN ('D11', 'D21') AND SALARY BETWEEN AND SELECT MIN(SALARY) AS MIN, MAX(SALARY) AS MAX, AVG(SALARY) AS AVG, COUNT(*) AS COUNT FROM EMPLOYEE WHERE EDLEVEL = 16 SELECT WORKDEPT, MIN(SALARY) AS MIN, MAX(SALARY) AS MAX, AVG(SALARY) AS AVG, COUNT(*) AS COUNT FROM EMPLOYEE GROUP BY WORKDEPT HAVING COUNT(*) > 5 SELECT WORKDEPT,SEX,MIN(SALARY) AS MIN,MAX(SALARY) AS MAX, SUM(SALARY) AS SUM FROM EMPLOYEE WHERE WORKDEPT LIKE 'D%' GROUP BY CUBE (WORKDEPT,SEX) END OF SOLUTION Copyright IBM Corp. 1998, 2001 Exercise 1. SQL Basics Review, CUBE & ROLLUP 1-5

30 1-6 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

31 Exercise 2. Create Objects What This Exercise Is About This exercise gives you an opportunity to implement a small data model. What You Should Be Able to Do At the end of the lab, you should be able to: Create tables with check constraints Create index Use referential integrity Create triggers Create views Understand the effect of CHECK OPTION in a view Appreciate some of the advantages of using views Introduction See the data model at the start of this Exercise Guide to get the column names and descriptions for each table. OS/390 Users: Be sure to add the correct IN clause to your CREATE TABLE statements. Ask the instructor if you forgot which IN clause to use. Required Materials Student handout SQL Reference Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-1

32 Exercise Instructions Problem 1 Harvey needs your help to create a database for his test environment. He has accurately defined the requirements, but he does not know the SQL syntax. You should help him to do the subsequent steps. Create the table EMPDEPT with these columns: EMPNO LASTNAME SALARY DEPTNO DEP_NAME The data types and null characteristics for these columns should be the same as for the columns with the same names in the EMPLOYEE and DEPARTMENT tables. These tables are described in our course data model. The definition of the table should limit the values for the yearly salary (SALARY) column to ensure that: The yearly salary for employees in department E11 (operations) must not exceed No employee in any department may have a yearly salary that exceeds The values in the EMPNO column should be unique. The uniqueness should be guaranteed via a unique index. Create the table HIGH_SALARY_RAISE with the following columns: EMPNO PREV_SAL NEW_SAL The data type for column EMPNO is CHAR(6). The other columns should be defined as DECIMAL(9,2). All columns in this table should be defined with NOT NULL. 2-2 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

33 Problem 2 Problem 3 Problem 4 After creating the table, you should add referential constraints. The primary key for the EMPDEPT table should be EMPNO. The EMPDEPT table should only allow values in column EMPNO which exist in the EMPLOYEE table. If an employee is deleted from the EMP table, the corresponding row in the EMPDEPT table should also be immediately deleted. The EMPDEPT table should only allow values in column DEPTNO which exist in the DEPARTMENT table. It should not be possible to delete a department from the DEPARTMENT table as long as a corresponding DEPTNO exists in the EMPDEPT table. Note: In DB2 for OS/390 the used sample tables are originally defined as views. You can not have a foreign key reference a view. Ask your instructor for the name and the qualifier of the tables which should be referenced. Klaus must update the yearly salaries for the employees of the EMPDEPT table. If the new value for a salary exceeds the previous value by 10 percent or more, Harvey wants to insert a row into the HIGH_SALARY_RAISE table. The values in this row should be the employee number, the previous salary, and the new salary. Create something in DB2 that will ensure that a row is inserted into the HIGH_SALARY_RAISE table whenever an employee of the EMPDEPT table gets a raise of 10 percent or more. Now, you should insert data in the EMPDEPT table. Use the combined contents of tables EMPLOYEE and DEPARTMENT as the source for your data. Did your insert work? If not, correct your INSERT statement so that you get only rows which satisfy the check constraints on the EMPDEPT table. Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-3

34 Problem 5 Problem 6 Problem 7 Problem 8 Problem 9 Harvey wants to test the table-level check constraint on the EMPDEPT table. Ethel Schneider works in the operations department. Her department number is E11, and her employee number is Try to set her yearly salary to the value of Does it work? Harvey wants to see if the trigger works. Elizabeth Pianka, whose employee number is , has been given a raise. Set her yearly salary to Inspect the HIGH_SALARY_RAISE table to see if the trigger worked. Create a view named VEMPPAY that contains one row for each employee in the company. Each row should contain employee number, last name, department number, and total earnings for the corresponding employee. Total earnings means salary plus bonus plus commission for the employee. Then, determine the average of the earnings for the departments by using the view you just created. Create a view named VEMP1 containing employee number, last name, yearly salary, and work department based on your TESTEMP table. Only employees with a yearly salary less than should be displayed when you use the view. Note: It is very important that you base this view on the TESTEMP table that was created for you or you created with the CRTABS member. Otherwise, you may get incorrect results in a later lab. Display the rows in the view in employee number sequence. Our employee with the employee number (Thompson) changed jobs and will get a new salary of Update the data for employee number using the view VEMP1. Display the view again, arranging the rows in employee number sequence. What happened? Is Thompson still in the view? Query the row of employee number in your TESTEMP table. Did the update work? Reset the salary of employee Thompson (empno = '000020') to the value of Create a view named VEMP2 which has the same definition as in problem 8, but add a CHECK OPTION. Again, base the view on your TESTEMP table. 2-4 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

35 Display the rows in the view in employee number sequence. Our employee with the employee number (Geyer) also changed jobs and will have a new salary of Update the data for employee number using the view VEMP2. Does the UPDATE statement work? Display the view again, arranging the rows in employee number sequence. Query Geyer's row in your TESTEMP table. Did the data in the base table change? END OF LAB Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-5

36 Exercise Instructions With Hints (Expected Results) Problem 1 Create the table EMPDEPT with these columns: EMPNO LASTNAME SALARY DEPTNO DEP_NAME The data types and null characteristics for these columns should be the same as for the columns with the same names in the EMPLOYEE and DEPARTMENT tables. These tables are described in our course data model. The definition of the table should limit the values for the yearly salary (SALARY) column to ensure that: The yearly salary for employees in department E11 (operations) must not exceed No employee in any department may have a yearly salary that exceeds The values in the EMPNO column should be unique. The uniqueness should be guaranteed via a unique index. Create the table HIGH_SALARY_RAISE with the following columns: EMPNO PREV_SAL NEW_SAL Result The data type for column EMPNO is CHAR(6). The other columns should be defined as DECIMAL(9,2). All columns in this table should be defined with NOT NULL. The CREATE statements for the EMPDEPT table, the unique index on the EMPDEPT table, and the HIGH_SALARY_RAISE table should all be successful. 2-6 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

37 Problem 2 Result Problem 3 Result Problem 4 Result After creating the table, you should add referential constraints. The primary key for the EMPDEPT table should be EMPNO. The EMPDEPT table should only allow values in column EMPNO which exist in the EMPLOYEE table. If an employee is deleted from the EMP table, the corresponding row in the EMPDEPT table should also be immediately deleted. The EMPDEPT table should only allow values in column DEPTNO which exist in the DEPARTMENT table. It should not be possible to delete a department from the DEPARTMENT table as long as a corresponding DEPTNO exists in the EMPDEPT table. Note: In DB2 for OS/390 the used sample tables are originally defined as views. You can not have a foreign key reference a view. Ask your instructor for the name and the qualifier of the tables which should be referenced. The ALTER statements which add the primary key and the foreign keys should execute successfully. Klaus must update the yearly salaries for the employees of the EMPDEPT table. If the new value for a salary exceeds the previous value by 10 percent or more, Harvey wants to insert a row into the HIGH_SALARY_RAISE table. The values in this row should be the employee number, the previous salary, and the new salary. Create something in DB2 that will ensure that a row is inserted into the HIGH_SALARY_RAISE table whenever an employee of the EMPDEPT table gets a raise of 10 percent or more. The CREATE TRIGGER statement should execute successfully. Now, you should insert data in the EMPDEPT table. Use the combined contents of tables EMPLOYEE and DEPARTMENT as the source for your data. Did your insert work? If not, correct your INSERT statement so that you get only rows which satisfy the check constraints on the EMPDEPT table. The initial INSERT should fail due to a check constraint violation. The INSERT should work after it has been modified so that none of the rows violates a check constraint. Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-7

38 Problem 5 Result Problem 6 Result Problem 7 Result Problem 8 Harvey wants to test the table-level check constraint on the EMPDEPT table. Ethel Schneider works in the operations department. Her department number is E11, and her employee number is Try to set her yearly salary to the value of Does it work? The UPDATE for Ethel Schneider will fail because it violates a check constraint. Harvey wants to see if the trigger works. Elizabeth Pianka, whose employee number is , has been given a raise. Set her yearly salary to Inspect the HIGH_SALARY_RAISE table to see if the trigger worked. The UPDATE for Elizabeth Pianka should succeed and should fire the trigger. You can verify that the trigger has fired by examining the contents of the HIGH_SALARY_RAISE table. You should see a row there for Elizabeth Pianka (EMPNO = ). EMPNO PREV_SAL NEW_SAL Create a view named VEMPPAY that contains one row for each employee in the company. Each row should contain employee number, last name, department number, and total earnings for the corresponding employee. Total earnings means salary plus bonus plus commission for the employee. Then, determine the average of the earnings for the departments by using the view you just created. WORKDEPT AVG_TOTAL_EARNINGS A B C D D E E E Create a view named VEMP1 containing employee number, last name, yearly salary, and work department based on your TESTEMP table. 2-8 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

39 Result Problem 9 Only employees with a yearly salary less than should be displayed when you use the view. Note: It is very important that you base this view on the TESTEMP table that was created for you or you created with the CRTABS member. Otherwise, you may get incorrect results in a later lab. Display the rows in the view in employee number sequence. Our employee with the employee number (Thompson) changed jobs and will get a new salary of Update the data for employee number using the view VEMP1. Display the view again, arranging the rows in employee number sequence. What happened? Is Thompson still in the view? Query the row of employee number in your TESTEMP table. Did the update work? You should see the following when you first display the view contents: EMPNO LASTNAME SALARY WORKDEPT THOMPSON B KWAN C GEYER E SMITH C01 You should see the following when you display the view contents after the update: EMPNO LASTNAME SALARY WORKDEPT KWAN C GEYER E SMITH C01 You should see the following when you query the TESTEMP table: EMPNO LASTNAME SALARY WORKDEPT THOMPSON B01 The update worked. Reset the salary of employee Thompson (empno = '000020') to the value of Create a view named VEMP2 which has the same definition as in problem 8, but add a CHECK OPTION. Again, base the view on your TESTEMP table. Display the rows in the view in employee number sequence. Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-9

40 Our employee with the employee number (Geyer) also changed also jobs and will have a new salary of Update the data for employee number using the view VEMP2. Does the UPDATE statement work? Display the view again, arranging the rows in employee number sequence. Query Geyer's row in your TESTEMP table. Result Did the data in the base table change? You should see the following when you first display the view contents: EMPNO LASTNAME SALARY WORKDEPT THOMPSON B KWAN C GEYER E SMITH C01 The SQLCODE (-161 in OS/390, SQL0161N on the workstation) indicates that the UPDATE did not work. The desired value for Geyer's SALARY, that is, 55000, was outside of the scope of the view (SALARY < 50000). The CHECK OPTION prevented the UPDATE. You should see the following when displaying the view after the update: EMPNO LASTNAME SALARY WORKDEPT THOMPSON B KWAN C GEYER E SMITH C01 You should see the following when you query the TESTEMP table after the update: EMPNO LASTNAME SALARY WORKDEPT GEYER E01 The data in the base table did not change. Remember that the data seen through the view is actually the base table data so this should not be a surprise. END OF LAB (with hints) 2-10 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

41 Solution Problem 1 CREATE TABLE EMPDEPT (EMPNO CHAR(6) NOT NULL, LASTNAME VARCHAR(15) NOT NULL, SALARY DECIMAL(9,2) CHECK(SALARY <= 50000), DEPTNO CHAR(3) NOT NULL, DEP_NAME VARCHAR(36) NOT NULL, CONSTRAINT DEPT_SAL CHECK (SALARY <= or DEPTNO <> 'E11')) --IN clause (OS/390 users only) ; CREATE UNIQUE INDEX EMPIND ON EMPDEPT(EMPNO); Problem 2 CREATE TABLE HIGH_SALARY_RAISE (EMPNO CHAR(6) NOT NULL, PREV_SAL DECIMAL(9,2) NOT NULL, NEW_SAL DECIMAL(9,2) NOT NULL) --IN clause (OS/390 users only) ; ALTER TABLE EMPDEPT ADD PRIMARY KEY (EMPNO); ALTER TABLE EMPDEPT ADD FOREIGN KEY (EMPNO) REFERENCES EMPLOYEE ON DELETE CASCADE; Problem 3 Problem 4 ALTER TABLE EMPDEPT ADD FOREIGN KEY (DEPTNO) REFERENCES DEPARTMENT ON DELETE RESTRICT; CREATE TRIGGER HIGH_SAL AFTER UPDATE OF SALARY ON EMPDEPT REFERENCING OLD AS O NEW AS N FOR EACH ROW MODE DB2SQL WHEN (N.SALARY >= O.SALARY * 1.1) INSERT INTO HIGH_SALARY_RAISE VALUES (N.EMPNO, O.SALARY, N.SALARY); Remember, OLD identifies the value that is in column SALARY before the update and NEW the value after the update. Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-11

42 Problem 5 Problem 6 Problem 7 The correct version of the INSERT is as follows: INSERT INTO EMPDEPT SELECT E.EMPNO, E.LASTNAME, E.SALARY, D.DEPTNO, D.DEPTNAME FROM EMPLOYEE E, DEPARTMENT D WHERE E.WORKDEPT = D.DEPTNO AND ((E.SALARY <= and E.WORKDEPT <> 'E11') OR (E.SALARY <= and E.WORKDEPT = 'E11')) ; The WHERE condition satisfies the check condition on the SALARY column of the EMPDEPT table (SALARY < 50000). The table constraint DEPT_SAL ensures that employees in department E11 have a yearly salary of 2800 or less. The condition "E.SALARY < = AND E.WORKDEPT < > 'E11'" selects employees who are not in department E11 and have a salary of less than The condition "E.SALARY < = AND E.WORKDEPT = 'E11'" selects employees who are in department E11 and have a salary of less than UPDATE EMPDEPT SET SALARY = WHERE EMPNO = '000280' The update fails because the table constraint DEPT_SAL ensures that employees in department E11 have a yearly salary of less than UPDATE EMPDEPT SET SALARY = WHERE EMPNO = '000280' This statement works is the maximum yearly salary for Ethel Schneider unless she changed departments. UPDATE EMPDEPT SET SALARY = WHERE EMPNO = '000160'; SELECT * FROM HIGH_SALARY_RAISE; Create the view: CREATE VIEW VEMPPAY (EMPNO, LASTNAME, WORKDEPT, TOTAL_EARNINGS) AS SELECT EMPNO, LASTNAME, WORKDEPT, SALARY + BONUS + COMM FROM EMPLOYEE; Use the view to determine the average total earnings for each department: 2-12 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

43 Problem 8 Problem 9 SELECT WORKDEPT, AVG(TOTAL_EARNINGS) AS AVG_TOTAL_EARNINGS FROM VEMPPAY GROUP BY WORKDEPT Create the view: CREATE VIEW VEMP1 AS SELECT EMPNO, LASTNAME, SALARY, WORKDEPT FROM TESTEMP WHERE SALARY < 50000; Determine which employees appear in the view: SELECT * FROM VEMP1 ORDER BY EMPNO; Update the data using the view: UPDATE VEMP1 SET SALARY = WHERE EMPNO = '000020'; Display the view again. SELECT * FROM VEMP1 ORDER BY EMPNO; See if the update worked: SELECT EMPNO, LASTNAME, SALARY, WORKDEPT FROM TESTEMP WHERE EMPNO = '000020'; Reset the salary for Thompson: UPDATE TESTEMP SET SALARY = WHERE EMPNO = '000020' Create the view: CREATE VIEW VEMP2 AS SELECT EMPNO, LASTNAME, SALARY, WORKDEPT FROM TESTEMP WHERE SALARY < WITH CHECK OPTION; Determine which employees appear in the view: SELECT * FROM VEMP2 ORDER BY EMPNO; Update the data using the view: Copyright IBM Corp. 1998, 2001 Exercise 2. Create Objects 2-13

44 UPDATE VEMP2 SET SALARY = WHERE EMPNO = '000050'; Display the view again. SELECT * FROM VEMP2 ORDER BY EMPNO; See if the update worked: SELECT EMPNO, LASTNAME, SALARY, WORKDEPT FROM TESTEMP WHERE EMPNO = '000050'; END OF SOLUTION 2-14 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001

45 Exercise 3. Joins What This Exercise Is About This exercise will give you the opportunity to code inner and outer joins. What You Should Be Able to Do Introduction Required Materials At the end of the lab, you should be able to: Code Inner and Outer Joins See the data model at the start of this Exercise Guide to get the column names and descriptions for each table. Note: Use the views VDEPARTMENT, VEMPLOYEE, and VPROJECT during this unit. Student handout SQL Reference Copyright IBM Corp. 1998, 2001 Exercise 3. Joins 3-1

46 Exercise Instructions Problem 1 Problem 2 Problem 3 Problem 4 Problem 5 Display all employees who work in the INFORMATION CENTER department. Show department number, employee number and last name for all employees in that department. Use the "old" SQL syntax that puts the join condition in the WHERE clause. Note: Use the views VDEPARTMENT, VEMPLOYEE, and VPROJECT during this unit. Solve problem 1 again using the newer SQL syntax that places the join condition in the ON clause. Bill needs a list of those employees whose departments are involved in projects. The list needs to show employee number, last name, department number, and project name. The list should be ordered by project names. Now Bill wants to see all employees, whether or not their departments are involved a project. The list needs to show the employee number, last name, department number, and project name. If the department of an employee is not involved in a project, display NULLs instead of the project name. The list should be ordered by employee number. Now Bill wants to see all projects, including those assigned to departments without employees. The list needs to show employee number, last name, department number, and project name. If a project is not assigned to a department having employees, NULLS should be displayed instead of the department number, employee number and last name. The list should be ordered by project name. 3-2 DB2 SQL for Experienced Users Copyright IBM Corp. 1998, 2001