Intro to MIS – MGS351 Databases and Data Warehouses Chapter 3

Chapter Overview Data Hierarchy Traditional File Environment Databases Relational, Hierarchical, Network Design and Normalization Data Warehousing

Data Hierarchy Database Table, File, Relation Records, Rows, Tuples Fields, Columns, Attributes Bytes Bits

Data Hierarchy

Traditional File Environment Issues: Data Redundancy Data Inconsistency Data Isolation Data Integrity Security Application / Data Dependence

Traditional File Processing

Database Approach Minimal data redundancy Data consistency Integration of data Sharing of data Uniform security, privacy and integrity Data independence

Database Environment

DBMS Components Data definition language (DDL): Specifies content and structure of database and defines each data element (data type, length, properties) Data manipulation language (DML): Manipulates data records in a database Data dictionary: Stores definitions of data elements, and data characteristics

Evolution of Databases

Relational Database Represents data as two-dimensional tables called relations Relates data across tables based on common data element Examples: DB2, Oracle, MS SQL Server, MySQL

Relational Database

Hierarchical Database Organizes data in a tree-like structure Supports one-to-many parent-child relationships Prevalent in large legacy systems

Hierarchical Database

Network Database Depicts data logically as many-to-many relationships Less flexible compared to RDBMS Lack support for ad-hoc and English language-like queries

Network Database

Database Design Conceptual / Logical Design – Abstract model of database from business perspective. Physical Design – determines how the database is arranged and optimized on storage devices.

ER Diagram

Business Intelligence Knowledge about your: Customers Competitors Partners Competitive environment Internal operations

Business Intelligence

Business Intelligence Online transaction processing (OLTP) - the gathering of input information, processing that information, and updating existing information to reflect the gathered and processed information. Operational databases - databases that support OLTP. Online analytical processing (OLAP) - the manipulation of information to support decision making.

Data Warehousing Data warehouse - a logical collection of information gathered from many different operational databases (Extract, Transform, Load) used to create business intelligence that supports business analysis activities and decision-making tasks.

Data Warehouse

Multidimensional Data Model

Data Marts Data Mart - a subset of a data warehouse in which only a focused portion of the data warehouse information is kept.

Data Mining Tools Data Mining - Used to find hidden patterns and previously unknown trends in data.

Databases and the Web