Lurus Kayu : Storing Organizational Information

Nursuhada Bt Abd Ghafar 4C BM111.

Relational 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

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
Entities and Attributes.

v Entity – a person, place, thing, transaction, or event about which information is stored

§The rows in each table contain the entities

§In Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities

v Attributes (fields, columns) – characteristics or properties of an entity class

§The columns in each table contain the attributes

§In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name

Keys and Relationships

v 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

v Potential relational database for Coca-Cola.

Relational Database Advantages

v Database advantages from a business perspective include

§Increased flexibility

§Increased scalability and performance

§Reduced information redundancy

§Increased information integrity (quality)

§Increased information security

Increased Flexibility

v 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

Increased Scalability and Performance.

v 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
Reduced Information Redundancy

v Databases reduce information redundancy

§Redundancy – the duplication of information or storing the same information in multiple places

v Inconsistency is one of the primary problems with redundant information

Increase Information Integrity (Quality )

v Information integrity – measures the quality of information

v Integrity constraint – rules that help ensure the quality of information

§Relational integrity constraint

§Business-critical integrity constraint

Increased Information Security

v Information is an organizational asset and must be protected

v 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

Database Management Systems

v Database management systems (DBMS) – software through which users and application programs interact with a database

DATA-DRIVEN WEB SITES.
v Data-driven Web sites – an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database