Data, Information, and Databases

Data vs. Information

• Data is raw, unprocessed facts
• Information results from processing raw data to reveal its meaning
• Information needs context to reveal its meaning
• Data forms the bedrock of information and eventually knowledge
• Knowledge is the familiarity and understanding of a subject
• Timely, relevant, and accurate information is key for decision-making
• Data management focuses on the proper retrieval, storage, and generation of data

Introducing Databases

• A database is a shared, integrated computer structure for storing data.
• End-user data: Raw facts of interest to the end user
• Metadata: Data through which end-user data is integrated and managed, describing data characteristics and relationships within the database

Database Management System (DBMS)

• A database management system is a collection of programs managing database structure and data access control

Role and Advantages of DBMS

• Aims to present a single, integrated view of data
• Advantages include:
• Better data integration
• Increased end-user productivity
• Improved data access and data sharing
• Improved decision-making capabilities
• Data security
• Minimized data inconsistency

Types of Databases

• Single-user database: supports one user at a time.
• Desktop database: single-user database on a PC.
• Multiuser database: supports multiple users at the same time
• Workgroup database: supports a small group of users.
• Enterprise database: supports many users across many departments
• Centralized database: Located at a single site
• Distributed database: Data distributed across different sites.
• General-purpose databases: Contains a wide variety of data disciplines
• Discipline-specific databases: Focuses on specific subject areas
• Operational database: Supports day-to-day operations
• Analytical database: Stores historical business metrics, and used exclusively for decision making which comprises of
• Data warehouse
• Online analytical processing (OLAP)
• Business intelligence captures and processes business data to generate information to support decision-making
• Unstructured data exists in its original format
• Structured data results from formatting unstructured data to facilitate storage and use
• Semistructured data is processed to some extent
• Extensible Markup Language (XML): represents data elements in textual format
• XML database supports the storage and management of unstructured XML data
• NoSQL (Not Only SQL) a new generation of DBMS that is not based on the traditional relational database model
• Its for web and mobile tech for human interaction
• Designed for unprecedented amounts of data

What is a DBMS

• A collection of programs that manage database structure and data access, stores relationships between the database,and define required access path

Importance of Database Design

• Pertains to activities that focus on the design of database structure to store and manage data
• Designs data repositories of integrated information
• Well-designed database enables better data management, produces accurate data
• Poor database design can cause errors and poor decisions

Evolution of File System Data

• Manual file systems use file cabinets and folders
• Computerized file systems use a data processing (DP) specialist to create a system to track data and produce reports
• Business users use spreadsheets such as excel to manipulate data in rows and columns
• Spreadsheets are misused as databases

Problems with File System Data Processing

• Lengthy development times
• Difficult to get quick answers
• Complex system administration
• Lack of security
• Limited data sharing
• Extensive programming

Structural and Data Dependence

• File system exhibits structural dependence
• Accessing the file depends on its structure
• Programs must be modified to fit new file structure
• Structural independence exists when changes to file structure do not affect data access
• Data dependence occurs when changes to data storage require changes to data access
• Data independence is when data storage changes, and the program can still access the data
• Significance of data dependence comes from the difference in logical data format and physical data management

Data Redundancy

• The same data is stored at different places
• Increases the probability of having different version of the same data
• Possible results of uncontrolled data redundancy include:
• Poor data security
• Data inconsistency
• Data-entry errors
• Data integrity problems
• Professionals use term "islands of information for scattered data locations

Data Anomalies

• Develops when required changes in redundant data are not made successfully
• Includes update, insertion, and deletion anomalies

Database Systems

• Logically related data stored in a single logical repository
• Data can be physically distributed among multiple storage facilities
• Its DBMS eliminates inconsistency, anomaly, and structural dependence problems

Database System Environment

• The system is an organization that regulates data collection, storage, management, and use of data
• It has 5 components:
• Hardware
• Software
• People
• Procedures
• Data
• Solutions should be cost-effective, tactical, and strategic

DBMS Function

• Data dictionary management - DBMS stores data elements and their relationship
• Data storage Management - DBMS manages the structures required for data storage
• Performance tuning - Ensures efficient performance
• Data transformation and presentation - DBMS transforms entered data to conform to required data structures
• Management - DBMS creates system for enforcing user security and data privacy
• Multiuser access control - DBMS uses algorithms to ensure multiple users can access the database without comprising integrity
• Backup and recovery management - DBMS provides backup and data recovery to ensure data integrity
• Recovery management - Deals with recovery after a failure
• Data integrity management - DBMS promotes and enforces integrity rules, ensuring data consistency
• Database access languages and application programming interfaces - DBMS provides data access through a query language
• Structured Query Language (SQL) - Is the de facto query language and data access standard supported by the majority of DBMS vendors
• communication interfaces - DBMS accepts end-user requests via interfaces

Managing the Database System

• Disadvantages include increased costs, management complexity, vendor dependence, and frequent upgrades needed