Databases and Data Warehouses Chapter 3 Intro to MIS - MGS351 Databases and Data Warehouses Chapter 3
Traditional File Environment Databases Overview Data Hierarchy Traditional File Environment Databases Relational, Hierarchical, Network Design and Normalization Data Warehousing
Fields, Columns, Attributes Bytes Bits 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 Advantages 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) CREATE TABLE Customers (Cust_no varchar2(12), FName char(30), Lname char(30), DOB date, Address varchar2(50));
DBMS Components Data manipulation language (DML): Manipulates data records in a database Select * from orders where customer_ID in (45, 16, 212) and order date > ‘20180220’;
DBMS Components Data dictionary: Stores definitions of data elements, and data characteristics
Evolution of Databases
Represents data as two-dimensional tables called relations 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
Depicts data logically as many-to-many relationships 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, optimized and tuned 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