BA471 Management Information Systems Databases

Database Fundamentals  Once upon a time, there were files Containing data “Flat files” not databases Enter data    Order System Orders Billing System Inventory System Bills Reports

Database Fundamentals  Systems needed each other’s data Order data needed for bills Qty data needed for orders … etc. Enter data    orders custs qty Order System Orders Billing System Inventory System Bills Reports

Database Fundamentals  So every night, data that needed to be shared had to be copied from one system to another.     What a waste of time and resources, not to mention ….redundant! Order Info Cust Info Qty Info transfer Order Info Cust Info Order Info

Database Fundamentals  A database is: A shared collection of data that is shared and used for multiple purposes. Symbol =

Database Fundamentals  A database consists of Tables  Made up of Rows Columns  That organize data so it’s usable by people and software

Database Fundamentals  Advantages of database approach Minimizes redundancy Treats data as an “asset” Standardizes data “One version of the truth”

Database Fundamentals  Problem? CUSTOMER Cust. Sat. System Sales System Billing System People Order System

Database Fundamentals  A DBMS is a group of programs that interface between an actual database and a person or a PROGRAM

Database Fundamentals  Examples of DBMS SQL MYSQL DB2 Oracle

Database Fundamentals  Applications are made up of Data in databases Processes in programs  Programs change – a lot – but data is stable  Creating new applications: Start with the data (Another database advantage is that you CAN start with the data when designing new applications.)

Database Fundamentals  Step 1: Define & Analyze the data Entity: A person, place, thing or event about which you want to capture data. Relationships: Between entities. Elements or Attributes: Characteristics of entities Allowed values

Database Fundamentals  Data Modeling – Designing the data A narrative & schematic model Defining entities, relationships, elements, attributes Later, becomes a physical database design

Database Fundamentals Banking Account Data Model Customer Account Type Billing cycle owns has follows

Database Fundamentals  Your role in Data Modeling SME Requirements analysis Data definitions

Database Fundamentals  In-class exercise: Western All Around Pets, Inc.

Database Fundamentals  Western All-Around Pets Pres & CEO COO Mgr Exotic Pets Mgr Domestic Pets CIO Business Analysts Controller Inventory Data Supervisor

Database Fundamentals  Data modeling – next steps Create an ERD  Relational model  Forward engineer a physical database (DDL)  Schema Define the data  Business definitions  Metadata  Domain

Database Fundamentals  Data Quality issues Ways in which data quality can be compromised  Errors at data entry  Software-introduced errors  Deterioration over time  Sabotage  Honest mistakes