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Database Concepts Introduction 5/22/2017 Database Concepts 1 Your Instructor • Meg McManus • My Background – 15 years in Database Administration – 3 years in Computer Operations – 2 years at UWF as Computer Science Instructor in Software Engineering – 8 years at OWC as Computer Science Instructor 5/22/2017 Database Concepts 2 Syllabus • • • • • How to reach me Purpose of course Textbook Grading Policies – Attendance – Allergies • Schedule 5/22/2017 Database Concepts 3 http://owcc-r-06.owc.edu/business/McManus/index.html Course Website includes all PowerPoint Presentations Homework Assignments Reference Material Test Reviews 5/22/2017 Database Concepts 4 Get your facts first, and then you can distort them as much as you please. Mark Twain 5/22/2017 Database Concepts 5 Chapter 1 Database Environment 5/22/2017 Database Concepts 6 Data vs. Information • Data – Raw material • Examples: PayRate, HoursWorked, PayPeriod, Commission Rate, SSN, Fname, Lname • Information – Data processed to increase knowledge in the person using the data – In other words…the Meaningful output • The Paycheck! 5/22/2017 Database Concepts 7 Database • In the strictest sense – – Organized collection of logically related data – Includes that which provides meaning in the user’s environment • Structured: numbers, text, dates • Unstructured: images, sound, video segments and documents 5/22/2017 Database Concepts 8 Database • Organized – Means that the data is • Easily stored • Easily manipulated • Easily retrieved by users • Related – Means that the • data describe a domain of interest to a group of users • users can use the data to answer questions concerning that domain 5/22/2017 Database Concepts 9 Context of Data Class Roster Course: CGS2541 Semester: Fall, 2006 CourseName: Database Concepts RefNo: 46409 Name ID Major GPA Mouse, Mickey SID-01 IT 4.00 Mouse, Minnie SID-02 Networking 4.00 Mulder, Fox SID-03 CIS 4.00 Scully, Dana SID-04 IT 4.00 Kirk, James T. SID-05 IT 4.00 Reynolds, Malcolm SID-06 CIS 4.00 Tam, River SID-07 EE 4.00 Crichton, John R. SID-08 CIS 4.00 5/22/2017 Database Concepts 10 Meaningful Information Percent by Major (2005) IT 37% CIS 37% Networking 13% 5/22/2017 EE 13% Database Concepts 11 Metadata • Data that describe the properties or characteristics of other data such as – Name – Data Type – Length, Min and Max values – Description – Source 5/22/2017 Database Concepts 12 Metadata Example Name Course Data Item Type Alphanumeric Reference Integer Length 30 1 Value Min Max Description Course ID and name Reference 1 9 Number Semester and year Semester Alphanumeric 10 Name Alphanumeric 30 ID Integer 9 Major Alphanumeric 4 GPA Decimal 3 0.00 5/22/2017 Student name Source Academic Unit Registrar Registrar Student Student ID (SSN) Student Student major Student grade 4.00 point average Database Concepts Student Academic Unit 13 File Processing 5/22/2017 Database Concepts 14 History • Original method – for storing and – manipulating data • Outmoded – given complexity of current data and user requirements • Replaced – by database processing systems 5/22/2017 Database Concepts 15 Disadvantages of File Processing • Program-Data Dependence – All programs maintain metadata for each file used • Duplication of Data – Different systems/programs have separate copies of same data • Limited Data Sharing – No centralized control of data 5/22/2017 Database Concepts 16 More Disadvantages of File Processing • Lengthy Development Timing – Programmers must design file formats from scratch • Excessive Program Maintenance – 80% of information systems budget – When 60% is considered normal for maintenance phase… 5/22/2017 Database Concepts 17 Data Dependency Issues • Data maintained by each programmer • Each application program requires code for each file’s metadata • Each application program requires own processing routines – for reading, inserting, updating and deleting data • Lack of coordination and central control • Non-standard file formats 5/22/2017 Database Concepts 18 File Vs. Database Processing File-oriented Information System Customer Records Customer Service Dept. Payroll Records Payroll Dept. Employee Records Personnel Dept. Inventory Records Purchasing Dept. Database-oriented Information System Consolidated Customer Purchasing Database Service Dept. Dept. Payroll Dept. 5/22/2017 Personnel Dept. Database Concepts 19 Data Redundancy Issues • Wastes space with duplicate data • Maintenance Migraines • Compromises data integrity – When data is changed in one file, not necessarily changed in all relative files 5/22/2017 Database Concepts 20 The Problem was Information Processing… The Solution? Database Processing 5/22/2017 Database Concepts 21 Database Processing • Provides – Central repository of shared data – Data is managed by a controlling agent – Data is stored in a standardized, convenient format 5/22/2017 Database Concepts 22 Database Processing Example Database Information System Consolidated Database Customer Service Dept. Payroll Dept. Purchasing Dept. Personnel Dept. Database Management System Customer Service Dept. Metadata Payroll Dept. Personnel Dept. Database Applications Purchasing Dept. 5/22/2017 Database Concepts DBMS Customers Payroll Employees Orders 23 Database Processing Advantages • Creates program-data independence – Data stored in repository – Allows organization to change and evolve • Minimizes data redundancy – Reduces wasted space • Improves data consistency – Data is updated once instead of in each file • Improves data sharing – Create different user views for different parts of the data 5/22/2017 Database Concepts 24 Database Processing Advantages • Improves data quality – Uses constraints on data • Enforcement of standards – Naming conventions – Data quality standards – Uniform procedures of accessing, updating and deleting data – Lack of control is one of the most common sources of failures in database administration 5/22/2017 Database Concepts 25 Database Processing Advantages • Increases application development productivity – Reduces time and cost in development • Improves data accessibility and responsiveness – End users have greater access to data • Reduces program maintenance – Can make changes • Improves decision support 5/22/2017 Database Concepts 26 Risks using Database Processing • Requires specialized, often new personnel trained in the database program • Installation & Management costs and complexity – Requires conversion costs when using legacy data • Requires explicit backup & recovery • Organizational conflicts 5/22/2017 Database Concepts 27 Components of the Database Environment • CASE Tools – computer-aided software engineering • Repository – centralized storehouse of metadata – Including data definitions, data relationships, screen and report formats 5/22/2017 Database Concepts 28 Components of the Database Environment • Database Management System (DBMS) – software for managing the database including control over access to data • Database – storehouse of the data – Designed to meet the needs of multiple users 5/22/2017 Database Concepts 29 Data Models • Capture the nature of and relationships among data • Used at different levels of abstraction – During conceptualization – During design 5/22/2017 Database Concepts 30 Components of the Database Environment • Application Programs – software used to create and maintain the database and provide information to the user • Database Administrators – personnel responsible for maintaining the database • System Developers – personnel responsible for designing databases and software 5/22/2017 Database Concepts 31 Components of the Database Environment • User Interface – Languages, text and graphical components designed to interact with various users • End Users – people who use the applications and databases – All requests for data are routed through the DBMS 5/22/2017 Database Concepts 32 Components of the Database Environment 5/22/2017 Database Concepts 33 Database Systems Evolution • • • • • • • • Flat files - 1960s - 1980s Hierarchical – 1970s - 1990s Network – 1970s - 1990s Relational – 1980s - present Object-oriented – 1990s - present Object-relational – 1990s - present Data warehousing – 1980s - present Web-enabled – 1990s - present 5/22/2017 Database Concepts 34 5/22/2017 Database Concepts 35 Database Elements • • • • • Enterprise Data Model Relational Databases Entities Use of Internet Technology Database Applications 5/22/2017 Database Concepts 36 Enterprise Data Model • Is a graphical model • Demonstrates – High-level entities – Relationships for the organization • Uses data warehouses – Collection of historical data – Aids in identifying patterns and trends 5/22/2017 Database Concepts 37 Relational Databases • Is a database technology that uses common keys to relate entities • Includes: – Tables – Relationships between entities – Types of keys representing relationships • Examples: Primary and Foreign 5/22/2017 Database Concepts 38 Entities • A person, place, object, event, or concept • Exists within the user’s environment • Of interest to management 5/22/2017 Database Concepts 39 Relationships • The relationship between entities so that useful information can be retrieved • Types – 1 to 1 – 1 to Many – Many to Many 5/22/2017 Database Concepts 40 Use of Internet Technology • • • • • Networks Telecommunications Distributed databases Client-server 3-tier architectures 5/22/2017 Database Concepts 41 Database Applications • Are application programs • Used to perform database activities – Create – Read – Update – Delete • For Users 5/22/2017 Database Concepts 42 Pine Valley Furniture Company Product Customer Places Has Is placed by Is for Contains Order 5/22/2017 Is contained in Database Concepts Order Line 43 Pine Valley Furniture Company Customer Places Is placed by One customer may place many orders, but each order is placed by one customer. This creates a One-to-many relationship Product Has Is for Contains Order 5/22/2017 Is contained in Database Concepts Order Line 44 Pine Valley Furniture Company Customer Places One order has many order lines, but each Product order line is associated with a single order. Has This creates a One-to-many relationship Is placed by Is for Contains Order 5/22/2017 Is contained in Database Concepts Order Line 45 Pine Valley Furniture Company Customer Places One product can be in many order lines, but each order refers to a single product. This creates a One-to-many relationship Is placed by Product Has Is for Contains Order 5/22/2017 Is contained in Database Concepts Order Line 46 Pine Valley Furniture Company Customer Places Each order involves many Product products and one product is involved in many orders. Has This creates a Many-to-many relationship Is placed by Is for Contains Order 5/22/2017 Is contained in Database Concepts Order Line 47 Pine Valley Relationship • Relationship between Order_line and Orders showing one-to-many relationship • Example from Microsoft Access 5/22/2017 Database Concepts 48 Relationships established in special columns that provide links between tables 5/22/2017 Database Concepts 49 Client/ Server System Architecture 5/22/2017 Database Concepts 50 Summary of Database Applications Adapted from White, 1995 5/22/2017 Database Concepts 51 Typical Data from a Personal Database 5/22/2017 Database Concepts 52 Workgroup Database with Local Area Network 5/22/2017 Database Concepts 53 An Enterprise Data Warehouse 5/22/2017 Database Concepts 54 Homework Assignment • Read Chapters 1 & 2 • Homework Assignment 1 • Read Project Case – Become familiar with Mountain View Project • Copy MVCH2.mdb file – Rearrange Relationships window • No line overlaps • All fields within tables visible • Print Relationships Report 5/22/2017 Database Concepts 55 5/22/2017 Database Concepts 56