Database Systems Database Systems: Design, Implementation, and Management, Rob and Coronel

 Data versus Information ◦ Data constitute building blocks of information ◦ Information produced by processing data ◦ Information reveals meaning of data ◦ Good, timely, relevant information key to decision making ◦ Good decision making key to organizational survival

 Major Database Concepts ◦ Data and information  Data  Raw facts  Formatted  Information  Processed data  Context  Convey meaning Purpose Decision making u 1997 Sales 37 Millions u Year, 4 digits, integer. Sales, 12 digits, 2 decimals u order, sort u group u plot u organize u statistical analysis

u Business Computer Lab Satisfaction Survey u Survery Link here Survery Link here u The survey collects data and saves it on a database. u The raw data is stored in a familiar format. Can you get information out of this data in this format? u No, the data is not processed to reveal its meaning!

 Database ◦ Shared ◦ Integrated ◦ computer structure that houses a collection of:  End user data - raw facts of interest to end user  Metadata, or data about data, through which the data are integrated. Provides a description of the data characteristics and the set of relationships that link the data found within the database.

 Database management system (DBMS)  A collection of programs that manages the database structure and control access to the data stored in the database  Integrates provides an “unified view of the data” by consolidating data from multiple sources into a common database  Shares the database among multiple applications and users  Hides database’s internal complexity from the end user and applications  Translates end users’ requests for data into complex instructions required to fulfill those requests

 Makes data management more efficient and effective  Facilitates data management by providing a framework of reference  Uses the metadata to describe the data found in the database  Query language allows quick answers to ad hoc queries  Valuable information generator  Provides better access to more and better-managed data  Promotes integrated view of organization’s operations  Reduces the probability of inconsistent data  Minimizes redundant data (data unnecessarily stored in multiple places)  The importance of minimizing and managing redundant data is better critical. Redundant data can introduce inconsistencies which negatively affects the quality of the data.

u Shared u Users u Applications u Integrated u Metadata u Enforces: u Data Management u Consistent Rules u Constraints u Security u Provides single integrated view of company data u Changes company’s culture u Promotes use and enforcement of business rules

 Hardware  Computer  Peripherals  Software  Operating systems software  DBMS software  Applications programs and utilities software  People  Systems administrators  Database administrators (DBAs)  Database designers  Systems analysts and programmers  End users  Procedures  Instructions and rules that govern the design and use of the database system  Data  Collection of facts stored in the database

The Database System Environment Interactions

 Number of Users  Single-user  Desktop database  Multiuser  Workgroup database  Enterprise database  Scope  Desktop  Workgroup  Enterprise  Location of the data  Centralized  Distributed  Intended Use  Transactional (Production/Operational)  Decision support (Data warehouse)

1.Data Dictionary Management 2.Data Storage Management 3.Data Transformation and Presentation 4.Security Management 5.Multi-User Access Control 6.Backup and Recovery Management 7.Data Integrity Management 8.Database Access Languages (DDL and DML) and Application Programming Interfaces 9.Database Communication Interfaces

 Entity – a person, place, thing or event about which data are to be collected and stored.  Importance of Good Design  Poor design results in unwanted data redundancy  Poor design generates errors leading to bad decisions  Practical Approach  Focus on principles and concepts of database design  Identify all required data  Organize data into smallest useful parts  Group data into related field to create tables  Identify the primary key for tables  Include pk as foreign key on related tables  Minimize data redundancies Teacher Student CourseClass