2a. What and Why Database? Lingma Acheson Department of Computer and Information Science IUPUI CSCI N207 Data Analysis with Spreadsheets 1

What is a Database? In a general sense, a database is any organized collection of data. Examples: –Grocery List –Audio CD Catalog –Phone Book –Airline Ticketing –Oncourse –Amazon –eBay 2

What is a Database? Forms of managing data: –Manual book keeping –Spreadsheets –WORD documents –Database management tool –… 3

Why Use a Database Tool? From a technical point of view, a database is organized collection of data stored using a database management tool, e.g. Microsoft Office Access, Oracle, Microsoft SQL Server, MySQL. Purpose for using a database tool –Better keep track of things –Obtain information quickly –Be able to analyze large amount of data and gain more insight 4

Why Use a Database Tool? Some data can be stored in a spreadsheet E.g. No problem with adding or deleting students. 5

Why Use a Database Tool? When data involves two different kinds yet related information – E.g. students and advisers information stored in a spreadsheet: 6

Why Use a Database Tool? Problems occur : –Modification problems: Deleting Row 6 will result in the loss of one adviser. If changing the in row 8, must change in row 5. If adding an adviser with no students, null values occur. 7

Why Use a Database Tool? –Other problems: Duplication, e.g. 20 students with one adviser would result in the same advisor information repeated 20 times. Confusion, e.g. if several different s were found for one adviser, which one is correct? How about using two spreadsheets, one stores information about students, and the other stores information about advisers? –Question: How to reflect the relationship between students and their advisers? 8

Why Use a Database Tool? Solution: Using a relational database, store students information in one table, and advisers information in another table, and the database system will allow you to define relationships among the two tables. E.g. STUDENT table and ADVISER table –Can add a student without touching the ADVISER table and vise versa. –Can link the two tables together to see the relationship. 9

Why Use a Database Tool? 10 STUDENT table: ADVISER table: