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2a. What and Why Database?

Lingma AchesonDepartment of Computer and Information Science

IUPUI

CSCI N207 Data Analysis with Spreadsheets

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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

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What is a Database?

• Forms of managing data:– Manual book keeping– Spreadsheets– WORD documents– Database management tool– …

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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

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Why Use a Database Tool?

• Some data can be stored in a spreadsheet• E.g.

• No problem with adding or deleting students.

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Why Use a Database Tool?

• When data involves two different kinds yet related information –E.g. students and advisers information stored in a spreadsheet:

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Why Use a Database Tool?

Problems occur :– Modification problems:

Deleting Row 6 will result in the loss of one adviser.If changing the email in row 8, must change in row 5.If adding an adviser with no students, null values occur.

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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 emails 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?

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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.

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Why Use a Database Tool?STUDENT table:

ADVISER table: