CS44800 Practice Project SQL Spring 2019

Transcription

1 CS44800 Practice Project SQL Spring 2019 Due: No Grade Total Points: 30 points Learning Objectives 1. Be familiar with the basic SQL syntax for DML. 2. Use a declarative programming model (SQL) to retrieve information from a database. 3. Use a procedural programming model (PL/SQL) to write database applications. 4. Write database applications using JDBC. Introduction You are going to use Oracle to perform some queries against a predefined database. The schema and sample data of the database are provided. You should be able to run the project on Purdue University Linux machines. You should be able to access your password and account name in your my.cs.purdue.edu, under the Local Accounts section. Remember that when you log into sqlplus your username needs to be <username>@csora Also, please do not attempt to change your password. Accounts are managed by Purdue and students do not have permissions to properly modify them attempting to change your password may result in your Oracle account becoming inaccessible. Information about getting your Oracle account and general initial configuration is available in: A tutorial on Oracle SQL and setting up your account will be given during PSOs sessions. Reference queries covered during these tutorials are available on the course site under this project listing as well. Feel free to contact the TAs or to attend office hours/pso sessions if you have any questions about Oracle SQL or the project. Besides, there is a SQL Tutorial available in the course website that you may find helpful for this practice project.

2 Your assignment In this project you will use the file: db.sql. Copy this file into your working directory. After entering the sqlplus environment, create and populate tables by using the following command: File db.sql will create the tables needed for this assignment. It will also fill the tables with some sample data. This will help you test your queries. Feel free to add your own data to help with testing your queries. IDE If you do not feel comfortable using the sqlplus command-line tool, you can use an IDE (with GUI) for your SQL/PLSQL development, such as Oracle SQL Developer. To configure the connection to the Oracle database installed in the University machines you will need to follow the following steps: 1. Add a new Connection (from the menu on the left). 2. Use claros.cs.purdue.edu as Hostname 3. Use 1524 as Port, and strep as SID. 4. Use your Oracle credential as Username and Password (you should find them in my.cs.purdue.edu).

3 The following section shows the schema of the database. Study the schema carefully. ProjectsInfo is a database used by a software development company to keep track of its projects. ProjectsInfo keeps track of the projects, the employees/managers working on the projects including the universities they were graduated from. The back-end database of the ProjectsInfo consists of the relations defined in the following schema: University(UnivId, UnivName) Department(DeptId, DeptName) Employee(EmpId, EmpName, DeptId, ZipCode, Salary) Project (ProjId, ProjName, Budget) Graduate(EmpId, UnivId, GradYear) EmpProject(EmpId, ProjId, StartDate, EndDate) ProjectManager(ProjId, MgrId, StartDate, EndDate) Relation University contains information about the universities where the employees graduated from. Attribute UnivId is the primary key. Relation Department contains information about the different departments in the company. Attribute DeptId is the primary key. The name of a department is unique. Relation Employee contains information about the employees in the company (including managers). Attribute EmpId is the primary key. Relation Project contains information about the projects that are running or that have been completed by the company. Attribute ProjId is the primary key. The name of a project is unique. Relation Graduate contains information about the university as well as the graduation year of each employee. It is assumed that each employee is graduated by exactly one degree from one university. Thus, the primary key is defined to be EmpId. Relation EmpProject contains information about all the projects an employee is/was working on. The primary key is composed of the three attributes: EmpId, ProjId, StartDate as an employee can rejoin a project s/he was released from. A NULL value in the EndDate attribute indicates "Current", i.e., the employee is currently working on that project. Relation ProjectManager contains information about all the managers of each project. A project has only one manager at a time, but the project can have different managers at different non-intersecting time frames. A manager is identified by Attribute MgrId and references the EmpId attribute of the Employee relation. The primary key is composed of the three attributes: ProjId, MgrId, StartDate. A NULL value in the EndDate attribute indicates "Current", i.e., the manager is currently managing that project.

4 Part 1: SQL Write SQL queries that answer the questions below (one SQL query per question but you are allowed to use nested queries and/or the "WITH" clause of Oracle) and run them on the Oracle system. Simple SELECT... FROM... WHERE queries should be sufficient for most queries, but some will require basic aggregation operators (e.g. COUNT(), MAX(), etc.), GROUP BY statements, and ORDER BY statements. If you are unfamiliar with Oracle SQL or any of these concepts, please feel free to attend PSOs or TA office hours or ask TAs if you have any questions. 1. Find the names of the employees who do not live in West Lafayette (Zip code or 47907). 2. Find the names of the projects that are currently managed by any manager. 3. Display the names of projects with at least 3 employees currently assigned. Sort the output in descending order of the number of employees per project. HINT. Check examples #10-12 from the SQL Tutorial. 4. For each university, display the university s name and the number of employees who have graduated from that university. 5. Display the name, department name, and graduation year of each Employee. 6. Find the names of all employees who work in Department 3. Print the names in ascending order. 7. Find the names of all Employees that graduated from Purdue or UCSB in the year 2008 or earlier that have worked on a Project with a budget of at least $50,000. HINT: Don t assume that the university ID of Purdue or UCSB will be the same in the grading test cases as they are in the provided data. Use Joins to solve instead of hard-coding the university ID. 8. For each zip code in the Employee table, print the number of employees that live in that zip code. Order the results in descending order by the number of employees, and then in ascending order by zip code. 9. Print the name(s) of the employee(s) who graduated first (i.e. the lowest graduation year). HINT. Find the earliest graduation year, and then print the name(s) of the employee(s) who graduated in that year. 10. Print the name of the project and the name of the employee that worked on that project. Do not repeat an employee for each project (in the case that the employee has joined the project more than once). Order the results in ascending order, first by the project name and second by the employee name. HINT. An employee may had joined a project in multiple times. You only need to show employees once.

5 Optional SQLs The following questions are a little more challenging and may require more advance SQL statements. 11. Display the names of employees from Department 3 whose salary is higher than any employee from Department Find the names of employees who have worked in all Projects. 13. Find the projects who have more than 4 employees assigned at any given time. 14. Find the Department with the highest payroll. Display the name of the Department, payroll, number of employees assigned. 15. Display the Purdue alumni who has worked in more than 1 project. Part 2: PL/SQL Implement triggers to enforce the following constraints: 1. No employee can work on the same project in overlapping time periods. 2. No project can have more than 5 employees assigned in overlapping time periods. Optional PL/SQL Implement triggers to add the following features: 1. Employee ID (EmpId) should be automatically generated by the database (e.g. an auto incremental identifier). 2. For a given project, list of the following information of the employees who are currently working on: employee complete name, name of the department the employee works in, zip code where they live in, university and graduate year. Part 3: JDBC Write a Java application to access your database using JDBC API. Your application should take the username and password used to log in to the Purdue Oracle Server as an input (from a file). The program should connect to the database and report the results of the following queries for a given employee id: 1. Retrieve all employees including: employee complete name, name of department the employee works in, and the zip code they live in. 2. Retrieve the projects an employee has worked on (including the number of times the employee has worked on that project). 3. Retrieve the managers that are in the same department as the employee. 4. Update the employee s graduate year by setting it to 5 years earlier. 5. Delete all projects that this employee has worked on. Delete the references in other tables to those deleted projects.

6 The JDBC driver for Oracle is in the lib subfolder. For more information about Oracle JDBC applications, please refer to the Oracle Guide. Since Oracle does not publish the JDBC drivers in the maven repositories, to configure your project using maven you will have to install first the JDBC library using the following command: mvn install:install-file -Dfile=lib/ojdbc8.jar -DgroupId=com.oracle -DartifactId=ojdbc8 -Dversion=18.3 -Dpackaging=jar Drop Drop all tables. Use statement SELECT * FROM user_catalog; to make sure that all the objects are dropped. You can use the droptables.sql script to drop all tables.

7 A useful strategy Here are some useful approaches for doing the project 1. Follow the introduction about the environment setup, connect to the Oracle server with your assigned Oracle account. 2. Try a few simple SQL statements until you are comfortable interacting with sqlplus. 3. Workout the SQL statements you need to solve the above queries 4. Use a text editor you are familiar with to create a.sql file that contains the necessary SQL statements for this project, and then call your sql script within sqlplus. Working within a text editor offers better editing functionality than the sqlplus interface available on the Purdue CS Linux machines. 5. Test your.sql file 6. Remember to divide and conquer. Test your.sql file continuously as you add the new SQL statements. 7. Most of the questions can be addressed with a simple query (inner joins, filters, etc). 8. In some cases, it s useful to divide the question in two (or more) subproblems. Then, you can join those subproblems using subqueries (e.g. IN, EXISTS) or a WITH clause. For example, check the hint for question 9.