6-1 DATABASE FUNDAMENTALS Information is everywhere in an organization Information is stored in databases –Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

6-2 DATABASE FUNDAMENTALS Database models include: –Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships –Network database model – a flexible way of representing objects and their relationships –Relational database model – stores information in the form of logically related two-dimensional tables

6-3 DATABASE ADVANTAGES Database advantages from a business perspective include –Increased flexibility –Increased scalability and performance –Reduced information redundancy –Increased information integrity (quality) –Increased information security

6-4 Increased Flexibility A well-designed database should: –Handle changes quickly and easily –Provide users with different views –Have only one physical view Physical view – deals with the physical storage of information on a storage device –Have multiple logical views Logical view – focuses on how users logically access information

6-5 Increased Scalability and Performance A database must scale to meet increased demand, while maintaining acceptable performance levels –Scalability – refers to how well a system can adapt to increased demands –Performance – measures how quickly a system performs a certain process or transaction

6-6 Reduced Redundancy Databases reduce information redundancy –Redundancy – the duplication of information or storing the same information in multiple places Inconsistency is one of the primary problems with redundant information

6-7 Increased Integrity (Quality) Information integrity – measures the quality of information Integrity constraint – rules that help ensure the quality of information –Relational integrity constraint – rule that enforces basic and fundamental information-based constraints –Business-critical integrity constraint – rule that enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraints

6-8 Increased Security Information is an organizational asset and must be protected Databases offer several security features including: –Password – provides authentication of the user –Access level – determines who has access to the different types of information –Access control – determines types of user access, such as read-only access

6-9 Entity – a person, place, thing, transaction, or event about which information is stored –The rows in each table contain the entities –In Figure 6.5 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities Entity class (table) – a collection of similar entities –In Figure 6.5 CUSTOMER, ORDER, ORDER LINE, DISTRIBUTOR, and PRODUCT entity classes RELATIONAL DATABASE FUNDAMENTALS

6-10 Attributes (fields, columns) – characteristics or properties of an entity class –The columns in each table contain the attributes –In Figure 6.5 attributes for CUSTOMER include: Customer ID Customer Name Contact Name Phone RELATIONAL DATABASE FUNDAMENTALS

6-11 Primary keys and foreign keys identify the various entity classes (tables) in the database –Primary key – a field (or group of fields) that uniquely identifies a given entity in a table –Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables RELATIONAL DATABASE FUNDAMENTALS

6-12 Potential relational database for Coca- Cola

6-13 DATABASE MANAGEMENT SYSTEMS Database management systems (DBMS) – software through which users and application programs interact with a database

6-14 DATABASE MANAGEMENT SYSTEMS Four components of a DBMS

6-15 Data Definition Component Data definition component – creates and maintains the data dictionary and the structure of the database The data definition component includes the data dictionary –Data dictionary – a file that stores definitions of information types, identifies the primary and foreign keys, and maintains the relationships among the tables

6-16 Data Definition Component Data dictionary essentially defines the logical properties of the information that the database contains

6-17 Data Manipulation Component Data manipulation component – allows users to create, read, update, and delete information in a database A DBMS contains several data manipulation tools: –View – allows users to see, change, sort, and query the database content –Report generator – users can define report formats –Query-by-example (QBE) – users can graphically design the answers to specific questions –Structured query language (SQL) – query language

6-18 Data Manipulation Component Sample report using Microsoft Access Report Generator

6-19 Data Manipulation Component Sample report using Access Query-By-Example (QBE) tool

6-20 Data Manipulation Component Results from the query in Figure 6.10

6-21 Data Manipulation Component SQL version of the QBE Query in Figure 6.10

6-22 Application Generation and Data Administration Components Application generation component – includes tools for creating visually appealing and easy-to- use applications Data administration component – provides tools for managing the overall database environment by providing faculties for backup, recovery, security, and performance IT specialists primarily use these components

6-23 INTEGRATING DATA AMONG MULTIPLE DATABASES Integration – allows separate systems to communicate directly with each other –Forward integration – takes information entered into a given system and sends it automatically to all downstream systems and processes –Backward integration – takes information entered into a given system and sends it automatically to all upstream systems and processes

6-24 INTEGRATING DATA AMONG MULTIPLE DATABASES Forward and backward integration

6-25 INTEGRATING DATA AMONG MULTIPLE DATABASES Building a central repository specifically for integrated information