1. CSCI 260 Database Applications Chapter 1 – Getting Started

2. 2 CSCI 260 – Database Apps Database processing is the heart of all applications today Database processing is the heart of all applications today The knowledge gained in this course will be valuable at job-hunting time The knowledge gained in this course will be valuable at job-hunting time Internet technology has tremendously amplified the need for database knowledge Internet technology has tremendously amplified the need for database knowledge Technology can be used inside organizations as well as outside for e-commerce applications Technology can be used inside organizations as well as outside for e-commerce applications

3. 3 Chapter 1 Objectives  Know the potential problems with lists  Understand the reasons for using a database  Understand how related tables avoid the problems of lists  Learn the components of database system  Learn the elements of a database  Learn the purpose of the database management system (DBMS)  Understand the functions of a database application

4. 4 Purpose of a Database The purpose of a database is to keep track of things The purpose of a database is to keep track of things Unlike a list or spreadsheet, a database may store information that is more complicated than a simple list Unlike a list or spreadsheet, a database may store information that is more complicated than a simple list

5. 5 Problems with Lists: Redundancy In a list, each row is intended to stand on its own. As a result, the same information may be entered several times In a list, each row is intended to stand on its own. As a result, the same information may be entered several times For Example: A list of Projects may include the Project Manager’s Name, ID, and Phone Extension. If a particular person is managing 10 projects, his/her information would have to be entered 10 times For Example: A list of Projects may include the Project Manager’s Name, ID, and Phone Extension. If a particular person is managing 10 projects, his/her information would have to be entered 10 times

6. 6 Problems with Lists: Multiple Themes In a list, each row may contain information on more than one theme. As a result, needed information may appear in the lists only if information on other themes is also present In a list, each row may contain information on more than one theme. As a result, needed information may appear in the lists only if information on other themes is also present For Example: A list of Projects may include Project Manager information (Name, ID, and Phone Extension) and Project information (Name, ID, StartDate, Budget) in the same row. For Example: A list of Projects may include Project Manager information (Name, ID, and Phone Extension) and Project information (Name, ID, StartDate, Budget) in the same row.

7. 7 List Modification Issues Redundancy and multiple themes create modification problems Redundancy and multiple themes create modification problems Deletion problems Deletion problems Update problems Update problems Insertion problems Insertion problems

8. 8 List Modification Issues

9. 9 Addressing the Information Complexities Relational databases are designed to address many of the information complexity issues Relational databases are designed to address many of the information complexity issues

10. 10 Relational Databases A relational database stores information in tables. Each informational topic is stored in its own table A relational database stores information in tables. Each informational topic is stored in its own table In essence, a relational database will break-up a list into several parts. One part for each theme in the list In essence, a relational database will break-up a list into several parts. One part for each theme in the list A Project List would be divided into a CUSTOMER Table, a PROJECT Table, and a PROJECT_MANAGER Table A Project List would be divided into a CUSTOMER Table, a PROJECT Table, and a PROJECT_MANAGER Table

11. 11 Putting the Pieces Back Together In our relational database we broke apart our list into several tables. Somehow the tables must be joined back together In our relational database we broke apart our list into several tables. Somehow the tables must be joined back together In a relational database, tables are joined together using the value of the data In a relational database, tables are joined together using the value of the data If a PROJECT has a CUSTOMER, the Customer_ID is stored as a column in the PROJECT table. The value stored in this column can be used to retrieve specific customer information from the CUSTOMER table If a PROJECT has a CUSTOMER, the Customer_ID is stored as a column in the PROJECT table. The value stored in this column can be used to retrieve specific customer information from the CUSTOMER table

12. 12 Sounds like More Work, Not Less A relational database is more complicated than a list A relational database is more complicated than a list However, a relational database minimizes data redundancy, preserves complex relationships among topics, and allows for partial data However, a relational database minimizes data redundancy, preserves complex relationships among topics, and allows for partial data Furthermore, a relational database provides a solid foundation for user forms and reports Furthermore, a relational database provides a solid foundation for user forms and reports

13. 13 Relational Database Example

14. 14 A Relational Database Solves the Problems of Lists

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20. 20 Structured Query Language (SQL) Structured Query Language (SQL) is an international standard for creating, processing and querying database and their tables Structured Query Language (SQL) is an international standard for creating, processing and querying database and their tables Many database applications use SQL to retrieve, format, report, insert, delete, and/or modify data for users Many database applications use SQL to retrieve, format, report, insert, delete, and/or modify data for users

21. 21 SQL Example

22. 22 SQL Example (Continued) SELECTCUSTOMER.CustomerName, CUSTOMER.Phone, COURSE.CourseDate, ENROLLMENT.AmountPaid, COURSE.Course, COURSE.Fee FROMCUSTOMER, ENROLLMENT, COURSE WHERECUSTOMER.CustomerNumber = ENROLLMENT.CustomerNumber AND COURSE.CourseNumber = ENROLLMENT.CourseNumber;

23. 23 SQL Example (continued)

24. 24 Database Systems The four components of a database system are: The four components of a database system are: Users Users Database Application Database Application Database Management System (DBMS) Database Management System (DBMS) Database Database

25. 25 Components of a Database System

26. 26 Users A user of a database system will A user of a database system will Use a database application to track things Use a database application to track things Use forms to enter, read, delete and query data Use forms to enter, read, delete and query data Produce reports Produce reports

27. 27 The Database A database is a self-describing collection of related records A database is a self-describing collection of related records Self-describing Self-describing The database itself contains the definition of its structure The database itself contains the definition of its structure Metadata is data describing the structure of the database data Metadata is data describing the structure of the database data Tables within a relational database are related to each other Tables within a relational database are related to each other

28. 28 The Database

29. 29 Database Management System (DBMS) A database management system (DBMS) serves as an intermediary between database applications and the database A database management system (DBMS) serves as an intermediary between database applications and the database The DBMS manages and controls database activities The DBMS manages and controls database activities The DBMS creates, processes and administers the databases it controls The DBMS creates, processes and administers the databases it controls

30. 30 Functions of a DBMS Create databases Create databases Create tables Create tables Create supporting structures Create supporting structures Read database data Read database data Modify database data (insert, update, delete) Modify database data (insert, update, delete) Maintain database structures Maintain database structures Enforce rules Enforce rules Control concurrency Control concurrency Provide security Provide security Perform backup and recovery Perform backup and recovery

31. 31 Referential Integrity Constraints The DBMS will enforce many constraints The DBMS will enforce many constraints Referential integrity constraints ensure that the values of a column in one table are valid based on the values in another table Referential integrity constraints ensure that the values of a column in one table are valid based on the values in another table If a 5 was entered as a CustomerID in the PROJECT table, a Customer having a CustomerID value of 5 must exist in the CUSTOMER table If a 5 was entered as a CustomerID in the PROJECT table, a Customer having a CustomerID value of 5 must exist in the CUSTOMER table

32. 32 Database Applications A database application is a set of one or more computer programs that serves as an intermediary between the user and the DBMS A database application is a set of one or more computer programs that serves as an intermediary between the user and the DBMS

33. 33 Functions of Database Applications Create and process forms Create and process forms Process user queries Process user queries Create and process reports Create and process reports Execute application logic Execute application logic Control database applications Control database applications

34. 34 Functions of Database Applications

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37. 37 Desktop Database Systems Desktop database systems typically: Desktop database systems typically: Have one application Have one application Have only a few tables Have only a few tables Are simple in design Are simple in design Involve only one computer Involve only one computer Support one user at a time Support one user at a time

38. 38 Desktop Database Systems

39. 39 Organizational Database Systems Organizational database systems typically: Organizational database systems typically: Support several users simultaneously Support several users simultaneously Include more than one application Include more than one application Involve multiple computers Involve multiple computers Are complex in design Are complex in design Have many tables Have many tables Have many databases Have many databases

40. 40 Organizational Database Systems

41. 41 Commercial DBMS Products Example Desktop DBMS Products Example Desktop DBMS Products Microsoft Access Microsoft Access Example Organizational DBMS Products Example Organizational DBMS Products Oracle’s Oracle Oracle’s Oracle Microsoft’s SQL Server Microsoft’s SQL Server IBM’s DB2 IBM’s DB2