sql

SQL1 - Practice Übungen zur Lehrveranstaltung Datenbanken / H.-G. Hopf Practice 1: Overview This practice covers the following topics: • Selecting all data from different tables • Describing the structure of tables • Performing arithmetic calculations and specifying column names • Using iSQL*Plus y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 1: Overview This is the first of many practices in this course. The solutions (if you require them) can be found in Appendix A. Practices are intended to cover all topics that are presented in the corresponding lesson. I A & l a Note the following location for the lab files: E:\labs\SQL1\labs O n r te If you are asked to save any lab files, save them at this location. To start ISQL*Plus, start your browser. You need to enter a URL to access iSQL*Plus. The URL requires the host name, which your instructor will provide. Enter the following command, replacing the host name with the value that your instructor provides: n I e l c a http://<HOSTNAME:5561>/isqlplus In any practice, there may be exercises that are prefaced with the phrases “If you have time” or “If you want an extra challenge.” Work on these exercises only if you have completed all other exercises in the allocated time and would like a further challenge to your skills. Perform the practices slowly and precisely. You can experiment with saving and running command files. If you have any questions at any time, ask your instructor. r O Oracle Database 10g: SQL Fundamentals I 1-37 Practice 1 Part 1 Test your knowledge: 1. Initiate an iSQL*Plus session using the user ID and password that are provided by the instructor. 2. iSQL*Plus commands access the database. True/False 3. The following SELECT statement executes successfully: SELECT last_name, job_id, salary AS Sal FROM employees; True/False 4. The following SELECT statement executes successfully: SELECT * FROM job_grades; True/False 5. There are four coding errors in the following statement. Can you identify them? SELECT sal x 12 FROM employee_id, last_name ANNUAL SALARY employees; y l n O e Part 2 Note the following location for the lab files: E:\labs\SQL1\labs I A s U If you are asked to save any lab files, save them at this location. To start ISQL*Plus, start your browser. You need to enter a URL to access iSQL*Plus. The URL requires the host name, which your instructor will provide. Enter the following command, replacing the host name with the value that your instructor provides: & l a O http://<HOSTNAME:5561>/isqlplus n r te You have been hired as a SQL programmer for Acme Corporation. Your first task is to create some reports based on data from the Human Resources tables. 6. Your first task is to determine the structure of the DEPARTMENTS table and its contents. n I e r O l c a Oracle Database 10g: SQL Fundamentals I 1-38 Practice 1 (continued) 7. You need to determine the structure of the EMPLOYEES table. y l n O e I A s U O The HR department wants a query to display the last name, job code, hire date, and employee number for each employee, with employee number appearing first. Provide an alias STARTDATE for the HIRE_DATE column. Save your SQL statement to a file named lab_01_07.sql so that you can disperse this file to the HR department. & l a n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 1-39 Practice 1 (continued) 8. Test your query in the lab_01_07.sql file to ensure that it runs correctly. … y l n O e 9. The HR department needs a query to display all unique job codes from the EMPLOYEES table. I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 1-40 Practice 1 (continued) Part 3 If you have time, complete the following exercises: 10. The HR department wants more descriptive column headings for its report on employees. Copy the statement from lab_01_07.sql to the iSQL*Plus text box. Name the column headings Emp #, Employee, Job, and Hire Date, respectively. Then run your query again. y l n … O e s U 11. The HR department has requested a report of all employees and their job IDs. Display the last name concatenated with the job ID (separated by a comma and space) and name the column Employee and Title. I A & l a O n r te n I e l c a r O … Oracle Database 10g: SQL Fundamentals I 1-41 Practice 1 (continued) If you want an extra challenge, complete the following exercise: 12. To familiarize yourself with the data in the EMPLOYEES table, create a query to display all the data from that table. Separate each column output by a comma. Name the column title THE_OUTPUT. … y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 1-42 Practice 2: Overview This practice covers the following topics: • Selecting data and changing the order of the rows that are displayed • Restricting rows by using the WHERE clause • Sorting rows by using the ORDER BY clause • Using substitution variables to add flexibility to your SQL SELECT statements y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 2: Overview In this practice, you build more reports, including statements that use the WHERE clause and the ORDER BY clause. You make the SQL statements more reusable and generic by including ampersand substitution. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-32 Practice 2 The HR department needs your assistance with creating some queries. 1. Due to budget issues, the HR department needs a report that displays the last name and salary of employees who earn more than $12,000. Place your SQL statement in a text file named lab_02_01.sql. Run your query. 2. Create a report that displays the last name and department number for employee number 176. 3. The HR departments needs to find high-salary and low-salary employees. Modify lab_02_01.sql to display the last name and salary for any employee whose salary is not in the range of $5,000 to $12,000. Place your SQL statement in a text file named lab_02_03.sql. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-33 Practice 2 (continued) 4. Create a report to display the last name, job ID, and start date for the employees with the last names of Matos and Taylor. Order the query in ascending order by start date. 5. Display the last name and department number of all employees in departments 20 or 50 in ascending alphabetical order by name. y l n O e s U 6. Modify lab_02_03.sql to display the last name and salary of employees who earn between $5,000 and $12,000 and are in department 20 or 50. Label the columns Employee and Monthly Salary, respectively. Resave lab_02_03.sql as lab_02_06.sql. Run the statement in lab_02_06.sql. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-34 Practice 2 (continued) 7. The HR department needs a report that displays the last name and hire date for all employees who were hired in 1994. 8. Create a report to display the last name and job title of all employees who do not have a manager. 9. Create a report to display the last name, salary, and commission of all employees who earn commissions. Sort data in descending order of salary and commissions. y l n O e s U 10. Members of the HR department want to have more flexibility with the queries that you are writing. They would like a report that displays the last name and salary of employees who earn more than an amount that the user specifies after a prompt. (You can use the query that you created in practice exercise 1 and modify it.) Save this query to a file named lab_02_10.sql. If you enter 12000 when prompted, the report displays the following results: I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-35 Practice 2 (continued) 11. The HR department wants to run reports based on a manager. Create a query that prompts the user for a manager ID and generates the employee ID, last name, salary, and department for that manager’s employees. The HR department wants the ability to sort the report on a selected column. You can test the data with the following values: manager ID = 103, sorted by employee last name: manager ID = 201, sorted by salary: manager ID = 124, sorted by employee ID: y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-36 Practice 2 (continued) If you have time, complete the following exercises: 12. Display all employee last names in which the third letter of the name is a. 13. Display the last name of all employees who have both an a and an e in their last name. If you want an extra challenge, complete the following exercises: 14. Display the last name, job, and salary for all employees whose job is sales representative or stock clerk and whose salary is not equal to $2,500, $3,500, or $7,000. y l n O e I A s U O 15. Modify lab_02_06.sql to display the last name, salary, and commission for all employees whose commission amount is 20%. Resave lab_02_06.sql as lab_02_15.sql. Rerun the statement in lab_02_15.sql. & l a n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 2-37 Practice 3: Overview of Part 1 This practice covers the following topics: • Writing a query that displays the current date • Creating queries that require the use of numeric, character, and date functions • Performing calculations of years and months of service for an employee y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 3: Overview of Part 1 Part 1 of this lesson’s practice provides a variety of exercises using different functions that are available for character, number, and date data types. I A O For Part 1, complete questions 1–6 at the end of this lesson. & l a n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-25 Practice 3 Part 1 1. Write a query to display the current date. Label the column Date. 2. The HR department needs a report to display the employee number, last name, salary, and salary increased by 15.5% (expressed as a whole number) for each employee. Label the column New Salary. Place your SQL statement in a text file named lab_03_02.sql. 3. Run your query in the file lab_03_02.sql. … y l n O e I A s U 4. Modify your query lab_03_02.sql to add a column that subtracts the old salary from the new salary. Label the column Increase. Save the contents of the file as lab_03_04.sql. Run the revised query. & l a O … n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-62 Practice 3 (continued) 5. Write a query that displays the last name (with the first letter uppercase and all other letters lowercase) and the length of the last name for all employees whose name starts with the letters J, A, or M. Give each column an appropriate label. Sort the results by the employees’ last names. Rewrite the query so that the user is prompted to enter a letter that starts the last name. For example, if the user enters H when prompted for a letter, then the output should show all employees whose last name starts with the letter H. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-63 Practice 3 (continued) 6. The HR department wants to find the length of employment for each employee. For each employee, display the last name and calculate the number of months between today and the date on which the employee was hired. Label the column MONTHS_WORKED. Order your results by the number of months employed. Round the number of months up to the closest whole number. Note: Your results will differ. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-64 Practice 3: Overview of Part 2 This practice covers the following topics: • Creating queries that require the use of numeric, character, and date functions • Using concatenation with functions • Writing case-insensitive queries to test the usefulness of character functions • Performing calculations of years and months of service for an employee • Determining the review date for an employee y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 3: Overview of Part 2 Part 2 of this lesson’s practice provides a variety of exercises using different functions that are available for character, number, and date data types. For Part 2, complete exercises 7–14. I A O Remember that for nested functions, the results are evaluated from the innermost function to the outermost function. & l a n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-61 Practice 3 (continued) Part 2 7. Create a report that produces the following for each employee: <employee last name> earns <salary> monthly but wants <3 times salary>. Label the column Dream Salaries. … y l n O e If you have time, complete the following exercises: 8. Create a query to display the last name and salary for all employees. Format the salary to be 15 characters long, left-padded with the $ symbol. Label the column SALARY. I A & l a s U O … n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-65 Practice 3 (continued) 9. Display each employee’s last name, hire date, and salary review date, which is the first Monday after six months of service. Label the column REVIEW. Format the dates to appear in the format similar to “Monday, the Thirty-First of July, 2000.” … y l n 10. Display the last name, hire date, and day of the week on which the employee started. Label the column DAY. Order the results by the day of the week, starting with Monday. O e I A & l a … s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-66 Practice 3 (continued) If you want an extra challenge, complete the following exercises: 11. Create a query that displays the employees’ last names and commission amounts. If an employee does not earn commission, show “No Commission.” Label the column COMM. … y l n O e s U 12. Create a query that displays the first eight characters of the employees’ last names and indicates the amounts of their salaries with asterisks. Each asterisk signifies a thousand dollars. Sort the data in descending order of salary. Label the column EMPLOYEES_AND_THEIR_SALARIES. I A & l a O n r te … n I e r O l c a Oracle Database 10g: SQL Fundamentals I 3-67 Practice 3 (continued) 13. Using the DECODE function, write a query that displays the grade of all employees based on the value of the column JOB_ID, using the following data: Job Grade AD_PRES A ST_MAN B IT_PROG C SA_REP D ST_CLERK E None of the above 0 y l n O e I A & l a s U O n r te n I e l c a r O 14. Rewrite the statement in the preceding exercise using the CASE syntax. Oracle Database 10g: SQL Fundamentals I 3-68 Practice 4: Overview This practice covers the following topics: • Writing queries that use the group functions • Grouping by rows to achieve more than one result • Restricting groups by using the HAVING clause y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 4: Overview At the end of this practice, you should be familiar with using group functions and selecting groups of data. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 4-25 Practice 4 Determine the validity of the following three statements. Circle either True or False. 1. Group functions work across many rows to produce one result per group. True/False 2. Group functions include nulls in calculations. True/False 3. The WHERE clause restricts rows prior to inclusion in a group calculation. True/False The HR department needs the following reports: 4. Find the highest, lowest, sum, and average salary of all employees. Label the columns Maximum, Minimum, Sum, and Average, respectively. Round your results to the nearest whole number. Place your SQL statement in a text file named lab_04_04.sql. 5. Modify the query in lab_04_04.sql to display the minimum, maximum, sum, and average salary for each job type. Resave lab_04_04.sql as lab_04_05.sql. Run the statement in lab_04_05.sql. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 4-26 Practice 4 (continued) 6. Write a query to display the number of people with the same job. Generalize the query so that the user in the HR department is prompted for a job title. Save the script to a file named lab_04_06.sql. y l n 7. Determine the number of managers without listing them. Label the column Number of Managers. Hint: Use the MANAGER_ID column to determine the number of managers. O e I A s U 8. Find the difference between the highest and lowest salaries. Label the column DIFFERENCE. & l a O n r te If you have time, complete the following exercises: 9. Create a report to display the manager number and the salary of the lowest-paid employee for that manager. Exclude anyone whose manager is not known. Exclude any groups where the minimum salary is $6,000 or less. Sort the output in descending order of salary. n I e r O l c a Oracle Database 10g: SQL Fundamentals I 4-27 Practice 4 (continued) If you want an extra challenge, complete the following exercises: 10. Create a query to display the total number of employees and, of that total, the number of employees hired in 1995, 1996, 1997, and 1998. Create appropriate column headings. 11. Create a matrix query to display the job, the salary for that job based on department number, and the total salary for that job, for departments 20, 50, 80, and 90, giving each column an appropriate heading. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 4-28 Practice 5: Overview This practice covers the following topics: • Joining tables using an equijoin • Performing outer and self-joins • Adding conditions y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 5: Overview This practice is intended to give you practical experience in extracting data from more than one table using SQL:1999–compliant joins. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-30 Practice 5 1. Write a query for the HR department to produce the addresses of all the departments. Use the LOCATIONS and COUNTRIES tables. Show the location ID, street address, city, state or province, and country in the output. Use a NATURAL JOIN to produce the results. 2. The HR department needs a report of all employees. Write a query to display the last name, department number, and department name for all employees. y l n O e I A … & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-31 Practice 5 (continued) 3. The HR department needs a report of employees in Toronto. Display the last name, job, department number, and department name for all employees who work in Toronto. 4. Create a report to display employees’ last name and employee number along with their manager’s last name and manager number. Label the columns Employee, Emp#, Manager, and Mgr#, respectively. Place your SQL statement in a text file named lab_05_04.sql. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-32 Practice 5 (continued) 5. Modify lab_05_04.sql to display all employees including King, who has no manager. Order the results by the employee number. Place your SQL statement in a text file named lab_05_05.sql. Run the query in lab_05_05.sql. … 6. Create a report for the HR department that displays employee last names, department numbers, and all the employees who work in the same department as a given employee. Give each column an appropriate label. Save the script to a file named lab_05_06.sql. y l n O e I A & l a s U O n r te … n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-33 Practice 5 (continued) 7. The HR department needs a report on job grades and salaries. To familiarize yourself with the JOB_GRADES table, first show the structure of the JOB_GRADES table. Then create a query that displays the name, job, department name, salary, and grade for all employees. … If you want an extra challenge, complete the following exercises: O e y l n 8. The HR department wants to determine the names of all employees who were hired after Davies. Create a query to display the name and hire date of any employee hired after employee Davies. I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-34 Practice 5 (continued) 9. The HR department needs to find the names and hire dates for all employees who were hired before their managers, along with their managers’ names and hire dates. Save the script to a file named lab5_09.sql. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 5-35 Practice 6: Overview This practice covers the following topics: • Creating subqueries to query values based on unknown criteria • Using subqueries to find out which values exist in one set of data and not in another y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 6: Overview In this practice, you write complex queries using nested SELECT statements. I A Paper-Based Questions You may want to create the inner query first for these questions. Make sure that it runs and produces the data that you anticipate before you code the outer query. & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 6-20 Practice 6 1. The HR department needs a query that prompts the user for an employee last name. The query then displays the last name and hire date of any employee in the same department as the employee whose name they supply (excluding that employee). For example, if the user enters Zlotkey, find all employees who work with Zlotkey (excluding Zlotkey). 2. Create a report that displays the employee number, last name, and salary of all employees who earn more than the average salary. Sort the results in order of ascending salary. y l n O e I A s U 3. Write a query that displays the employee number and last name of all employees who work in a department with any employee whose last name contains a u. Place your SQL statement in a text file named lab_06_03.sql. Run your query. & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 6-21 Practice 6 (continued) 4. The HR department needs a report that displays the last name, department number, and job ID of all employees whose department location ID is 1700. Modify the query so that the user is prompted for a location ID. Save this to a file named lab_06_04.sql. 5. Create a report for HR that displays the last name and salary of every employee who reports to King. y l n O e I A s U 6. Create a report for HR that displays the department number, last name, and job ID for every employee in the Executive department. & l a O n r te n I e If you have time, complete the following exercise: 7. Modify the query in lab_06_03.sql to display the employee number, last name, and salary of all employees who earn more than the average salary and who work in a department with any employee whose last name contains a u. Resave lab_06_03.sql as lab_06_07.sql. Run the statement in lab_06_07.sql. r O l c a Oracle Database 10g: SQL Fundamentals I 6-22 Practice 7: Overview In this practice, you use the set operators to create reports: • Using the UNION operator • Using the INTERSECTION operator • Using the MINUS operator y l n O e Copyright © 2004, Oracle. All rights reserved. Practice 7: Overview In this practice, you write queries using the set operators. I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 7-24 Practice 7 1. The HR department needs a list of department IDs for departments that do not contain the job ID ST_CLERK. Use set operators to create this report. 2. The HR department needs a list of countries that have no departments located in them. Display the country ID and the name of the countries. Use set operators to create this report. y l n 3. Produce a list of jobs for departments 10, 50, and 20, in that order. Display job ID and department ID using set operators. O e I A & l a s U O 4. Create a report that lists the employee IDs and job IDs of those employees who currently have a job title that is the same as their job title when they were initially hired by the company (that is, they changed jobs but have now gone back to doing their original job). n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 7-25 Practice 7 (continued) 5. The HR department needs a report with the following specifications: - Last name and department ID of all the employees from the EMPLOYEES table, regardless of whether or not they belong to a department - Department ID and department name of all the departments from the DEPARTMENTS table, regardless of whether or not they have employees working in them Write a compound query to accomplish this. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 7-26 Practice 8: Overview This practice covers the following topics: • Inserting rows into the tables • Updating and deleting rows in the table • Controlling transactions y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 8: Overview In this practice, you add rows to the MY_EMPLOYEE table, update and delete data from the table, and control your transactions. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 8-40 Practice 8 The HR department wants you to create SQL statements to insert, update, and delete employee data. As a prototype, you use the MY_EMPLOYEE table, prior to giving the statements to the HR department. Insert data into the MY_EMPLOYEE table. 1. Run the statement in the lab_08_01.sql script to build the MY_EMPLOYEE table to be used for the lab. 2. Describe the structure of the MY_EMPLOYEE table to identify the column names. 3. Create an INSERT statement to add the first row of data to the MY_EMPLOYEE table from the following sample data. Do not list the columns in the INSERT clause. Do not enter all rows yet. ID LAST_NAME FIRST_NAME USERID SALARY 1 Patel Ralph rpatel 895 2 Dancs Betty bdancs 860 3 Biri Ben bbiri 1100 4 Newman Chad cnewman 750 5 Ropeburn Audrey aropebur I A y l n O e s U 1550 4. Populate the MY_EMPLOYEE table with the second row of sample data from the preceding list. This time, list the columns explicitly in the INSERT clause. 5. Confirm your addition to the table. & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 8-41 Practice 8 (continued) 6. Write an insert statement in a dynamic reusable script file named loademp.sql to load rows into the MY_EMPLOYEE table. Concatenate the first letter of the first name and the first seven characters of the last name to produce the user ID. Save this script to a file named lab_08_06.sql. 7. Populate the table with the next two rows of sample data by running the insert statement in the script that you created. 8. Confirm your additions to the table. 9. Make the data additions permanent. Update and delete data in the MY_EMPLOYEE table. 10. Change the last name of employee 3 to Drexler. 11. Change the salary to $1,000 for all employees who have a salary less than $900. 12. Verify your changes to the table. y l n O e I A 13. Delete Betty Dancs from the MY_EMPLOYEE table. 14. Confirm your changes to the table. & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 8-42 Practice 8 (continued) 15. Commit all pending changes. Control data transaction to the MY_EMPLOYEE table. 16. Populate the table with the last row of sample data by using the statements in the script that you created in step 6. Run the statements in the script. 17. Confirm your addition to the table. 18. 19. 20. 21. Mark an intermediate point in the processing of the transaction. Empty the entire table. Confirm that the table is empty. Discard the most recent DELETE operation without discarding the earlier INSERT operation. 22. Confirm that the new row is still intact. y l n O e 23. Make the data addition permanent. & l a I A s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 8-43 Practice 9: Overview This practice covers the following topics: • Creating new tables • Creating a new table by using the CREATE TABLE AS syntax • • Verifying that tables exist Dropping tables y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 9: Overview Create new tables by using the CREATE TABLE statement. Confirm that the new table was added to the database. Create the syntax in the command file, and then execute the command file to create the table. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 9-37 Practice 9 1. Create the DEPT table based on the following table instance chart. Place the syntax in a script called lab_09_01.sql, then execute the statement in the script to create the table. Confirm that the table is created. Column Name ID NAME Key Type Primary key Nulls/Unique FK Table FK Column Data type NUMBER VARCHAR2 Length 7 25 2. Populate the DEPT table with data from the DEPARTMENTS table. Include only columns that you need. 3. Create the EMP table based on the following table instance chart. Place the syntax in a script called lab_09_03.sql, and then execute the statement in the script to create the table. Confirm that the table is created. y l n Column Name ID LAST_NAME FIRST_NAME Key Type I A Nulls/Unique FK Table FK Column Data type NUMBER Length 7 r e nt na 25 s U DEPT ID VARCHAR2 NUMBER 25 7 I e l c a r O l& VARCHAR2 O O e DEPT_ID Oracle Database 10g: SQL Fundamentals I 9-38 Practice 9 (continued) 4. Create the EMPLOYEES2 table based on the structure of the EMPLOYEES table. Include only the EMPLOYEE_ID, FIRST_NAME, LAST_NAME, SALARY, and DEPARTMENT_ID columns. Name the columns in your new table ID, FIRST_NAME, LAST_NAME, SALARY , and DEPT_ID, respectively. 5. Drop the EMP table. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 9-39 Practice 10: Overview of Part 2 This practice covers the following topics: • Creating sequences • Using sequences • Creating nonunique indexes • Creating synonyms y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 10: Overview of Part 2 Part 2 of this lesson’s practice provides you with a variety of exercises in creating and using a sequence, an index, and a synonym. Complete questions 7–10 at the end of this lesson. & l a I A O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 10-41 Practice 10 Part 1 1. The staff in the HR department wants to hide some of the data in the EMPLOYEES table. They want a view called EMPLOYEES_VU based on the employee numbers, employee names, and department numbers from the EMPLOYEES table. They want the heading for the employee name to be EMPLOYEE. 2. Confirm that the view works. Display the contents of the EMPLOYEES_VU view. … 3. Using your EMPLOYEES_VU view, write a query for the HR department to display all employee names and department numbers. y l n O e … I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 10-42 Practice 10 4. Department 50 needs access to its employee data. Create a view named DEPT50 that contains the employee numbers, employee last names, and department numbers for all employees in department 50. You have been asked to label the view columns EMPNO, EMPLOYEE, and DEPTNO. For security purposes, do not allow an employee to be reassigned to another department through the view. 5. Display the structure and contents of the DEPT50 view. 6. Test your view. Attempt to reassign Matos to department 80. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 10-43 Practice 10 Part 2 7. You need a sequence that can be used with the primary key column of the DEPT table. The sequence should start at 200 and have a maximum value of 1,000. Have your sequence increment by 10. Name the sequence DEPT_ID_SEQ. 8. To test your sequence, write a script to insert two rows in the DEPT table. Name your script lab_10_08.sql. Be sure to use the sequence that you created for the ID column. Add two departments: Education and Administration. Confirm your additions. Run the commands in your script. 9. Create a nonunique index on the NAME column in the DEPT table. 10. Create a synonym for your EMPLOYEES table. Call it EMP. y l n O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 10-44 Practice 11: Overview This practice covers the following topics: • Querying the dictionary views for table and column information • Querying the dictionary views for constraint information • Querying the dictionary views for view information • Querying the dictionary views for sequence information • Querying the dictionary views for synonym information • Adding a comment to a table and querying the dictionary views for comment information y l n O e Copyright © 2004, Oracle. All rights reserved. s U Practice 11: Overview In this practice, you query the dictionary views to find information about objects in your schema. I A & l a O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 11-21 Practice 11 1. For a specified table, create a script that reports the column names, data types, and data types’ lengths, as well as whether nulls are allowed. Prompt the user to enter the table name. Give appropriate aliases to the columns DATA_PRECISION and DATA_SCALE. Save this script in a file named lab_11_01.sql. For example, if the user enters DEPARTMENTS, the following output results: 2. Create a script that reports the column name, constraint name, constraint type, search condition, and status for a specified table. You must join the USER_CONSTRAINTS and USER_CONS_COLUMNS tables to obtain all of this information. Prompt the user to enter the table name. Save the script in a file named lab_11_02.sql. For example, if the user enters DEPARTMENTS, the following output results: y l n O e I A s U 3. Add a comment to the DEPARTMENTS table. Then query the USER_TAB_COMMENTS view to verify that the comment is present. & l a O n r te 4. Find the names of all synonyms that are in your schema. n I e r O l c a Oracle Database 10g: SQL Fundamentals I 11-22 Practice 11 5. You need to determine the names and definitions of all of the views in your schema. Create a report that retrieves view information: the view name and text from the USER_VIEWS data dictionary view. Note: Another view already exists. The EMP_DETAILS_VIEW was created as part of your schema. Also, if you completed practice 10, you will see the DEPT50 view. Note: To see more contents of a LONG column, use the iSQL*Plus command SET LONG n, where n is the value of the number of characters of the LONG column that you want to see. y l n 6. Find the names of your sequences. Write a query in a script to display the following information about your sequences: sequence name, maximum value, increment size, and last number. Name the script lab_11_06.sql. Run the statement in your script. O e I A & l a s U O n r te n I e r O l c a Oracle Database 10g: SQL Fundamentals I 11-23