7/17: Database Management Where we are Database concepts Database management: considerations Types of databases Technical Foundations: Database structures Accessing databases Database development

Where we are Management of IS (ch. 13-15) Development of IS (ch. 3) Technology of IS (ch. 4-7) Applications of IS (ch. 8-12) Development of IS (ch. 3) Management of IS (ch. 13-15) Foundation Concepts of IS (ch. 1-2)

Database concepts Parts of a database (smallest to largest) Character Field (attribute) Record (entity) File (table) Database

What is a database? A database is a collection of information that you organize and access according to the logical structure of that information. Two essential parts: Information Logical structure & relationships Semester Database

Database Management Idea: to have information available to a wide array of user groups Customized format for each user group Data modification to be made once, not many times What does this involve? Hardware Software People Data Networks

Database Management DBMS: Database Management System Database development Database manipulation (interrogation) Database maintenance Application (Interface) development Examples of DBMSes Microsoft Access, Lotus Approach Oracle 8 IBM’s DB2 FileMaker Pro, FoxPro, Paradox, Sybase

DBMS: Database Development People: Database Administrators & Specialists DDL: Data Definition Language (a.k.a. Data Definition Subsystem) Data Dictionary Defines what data can go where in a database Defines relationships

DBMS: Database Manipulation People: End users Query Languages SQL: Structured Query Language QBE: Query by Example Report Generators Premade report formats

DBMS: Database Maintenance Transaction Processing Programs Updating information Adding new information Information Validation Backup & recovery Security management

DBMS: Application Development Developing programs and/or forms to allow input of information

Conceptual Types of Databases Operational Databases - Day-to-day operations Analytical Databases - Management analysis Data Warehouses Huge conglomeration of operational & analytical DBs Used for historical analysis End User Databases Distributed Databases – for easier access External Databases – Internet, stats, LEXIS/NEXIS, etc.

Database Structures Hierarchical Network Relational Object-Oriented Multidimensional Object-Oriented How to choose: let the data dictate the model Automobile Electrical Mechanical Fuses Wiring Valves

Hierarchical Structure Similar to some website layouts Relationships: one-to-many (EX: many fuses in electrical category) Automobile Electrical Mechanical Fuses Wiring Valves

Network Structure Different aspects to the relationships, so many possible relationships Relationships: many-to-many (EX: valves associated with metal & plastic, plastic assoc. with fuses & valves) Automobile Electrical Mechanical Wiring Fuses Valves Metal Plastic

Relational Structure Data stored in tables, with relationships between tables Multidimensional: data stored in 3D, not 2D

Object-Oriented Structure Data stored in objects with defined relationships Objects have attributes(data) & operations(methods). Bank Account Object Attributes: Customer Balance Interest Operations: Deposit ($) Withdraw ($) Get owner Checking Account Object Savings Account Object Attributes: Credit Line Monthly Statement Operations: Calc. Interest Print Monthly Statement Attributes: # Withdrawals # Deposits Qtrly Statement Operations: Calc. Interest Print Qtrly Statement

Accessing Databases Key Fields (unique identifiers) in relational DBs Internet: URLs (Uniform Resource Locators) Sequential access (like a cassette tape) Direct access (like a hard drive) – requires a index or key transformation

Database Development Action Steps Products of Steps Data Planning: Develop model of business Processes Requirement Specification: Define info needs of end users Conceptual Design: Express reqs in high-level model Logical Design: Translate high- level model into data model Physical Design: Determine data storage structure & access methods Enterprise model of business processes Description of users’ needs Conceptual data models w/ relationships Logical data models Physical data models inc. access methods Products of Steps