Chapter # 04Information and Databases Information and Database

Chapter # 04Information and Databases Database “Is an organized collection of records/information that is made-up of related records.” “Refers to a structured collection of electronically stored data which is controlled, accessed through computers based on predefined relationships between predefined types of data items related to a specific business situation or problem”

Chapter # 04Information and Databases Database Management System : A DBMS is an integrated set of programs used to define, update and control databases. A DBMS is an integrated set of programs used to define, update and control databases. File : Is a set of related records that contains the same fields in the same order and same format. Is a set of related records that contains the same fields in the same order and same format. Record : Record is a set of fields, each of which is related to the same thing, person or event. Record is a set of fields, each of which is related to the same thing, person or event. Key : A key is field that uniquely identifies which person, thing or event the record describes. A key is field that uniquely identifies which person, thing or event the record describes. Field : A field is a group of characters that have a predefined meaning. A field is a group of characters that have a predefined meaning.

Chapter # 04Information and Databases Types of Data Pre-defined data Items TextImagesAudioVideo

Chapter # 04Information and Databases Data Modeling : The process of defining what data is used or produced in an information system and how that data is organized. Entities :The specific things, database collects data about. Entity type :The kind of things, data is collected about Relationship :The way specific entities of one type might related to specific entities of the other type

Chapter # 04Information and Databases Entity Relation Diagram :Technique for identifying the entity types in a situation and diagramming the relationship between those entity types. Type of Relationships : One-to-One relationshipOne-to-One relationship One to Many relationshipOne to Many relationship Many to Many relationsMany to Many relations

Relational Structure of Databases Primary Key Filed: A column which uniquely identifies a in a table Foreign Key: Which refer to a specific record of an other table. Properties of Key Field : Unique, Not Null, and Indexed

Data Modeling – Entity Relation Diagram

Chapter # 04Information and Databases Types of Databases Relational Databses Multi-Dimensional Databases Data Warehouse Geographical Information systems Text and Image databases Hyper Databases and Web Web page HTMLURL Indexes and Search Engines

Data Warehousing

Chapter # 04Information and Databases Roles of DBMS Controlling and Organizing data to increase its value Efficient way to organize data Efficient way to organize data Improves data Accuracy Improves data Accuracy Discouraging Data Redundancy Discouraging Data Redundancy Flexibility Flexibility Supports Data Security (controlled access / recovery procedures) Supports Data Security (controlled access / recovery procedures) Making Programming more efficient Provides consistent and centralized defining methods Provides consistent and centralized defining methods

Chapter # 04Information and Databases Range of DBMS Functions Defining the database Data Definition Data Definition Data Dictionary Data Dictionary Methods of Accessing data in a Computer Systems Sequential Access Sequential Access Direct Access Direct Access Indexed Sequential Access (ISAM) Indexed Sequential Access (ISAM) Processing transactions Controlling Distributed Databases Backup and Recovery Supporting Database Administration

Chapter # 04Information and Databases Evaluating Data as a Source (Usefulness) Information Quality : Accuracy Precision Accuracy Precision CompletenessAge CompletenessAge TimelinessSource TimelinessSource Information Accessibility: AvailabilityAdmissibility AvailabilityAdmissibility Information Presentation : Level of SummarizationFormat Level of SummarizationFormat Information Security : Access RestrictionEncryption Access RestrictionEncryption

Chapter # 04Information and Databases Models as Component of IS Mental Models Mathematical Model What-if Questions Virtual Reality : The Ultimate interactive Model