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• Lesson 2 focuses on the fundamental concepts of database systems

Learning Outcomes

• Understand the differences between data and information
• Learn to describe databases
• Learn to identify the different types of databases
• Explain the importance of databases
• Identify database system components
• Describe the function of a database management system

Nature of Databases

• Databases interact in many everyday activities
• For example banking, pharmacy, online shopping
• Data are stored which include user data, product information and sales data

Why Use Databases

• Data is generated from birth to death
• The trail starts with the birth certificate and continues until the death certificate
• Databases are an effective approach to storing and managing data
• Databases ensure data persistence and shareability in a secure manner

Data vs Information

• Data is the start consisting of raw facts, or unprocessed data
• Information is what you get by processing data

Key points

• Data consists of the building blocks of information
• Information is what you get by processing data
• Information reveals the meaning of data
• Accurate, relevant and timely information ensures good decision making
• Good decision making helps survival in a global environment

Data Management

• Data management is a core activity for any business, government, service orginization or charity
• Data management revolves around data collection, storage and retrieval
• Common functions include addition, deletion, modification, and listing

Database Defined

• Databases are shared, integrated structures that houses a collection of related data
• Databases feature 2 types of data: end-user data (raw facts) and metadata (data characteristics)
• Metadata components may examples such as Name = text, Birthdate = date, Age = number

Database Management System Defined

• A DBMS is a collection of programs that manages the database structure and controls access
• A database is like an electronic file, where the DBMS helps manage the content
• DBMS are computerized data-keeping systems that provides the tools to create, protect, read, update and delete data
• It manages security, data integrity and concurrency

DMBS role and advantages

• DBMS serves as the main link between users and databases
• The database structure consists of a collection of files, accessible only through the DBMS
• The end user (or application program) views a database as an integrated whole
• The DBMS receives all application requests
• The DBMS translates requests into complex operations, hiding internal complexity

Advantages of DBMS:

• Improved data sharing and access to better managed data
• Improved data security with increased attention towards preventing data breaches
• Better data integration allowing wider access and integrated view of the organization's operations

Further Advantages of DBMS:

• Minimized data inconsistency by reducing different data versions in different places
• Improved data access answering ad hoc (spur of the moment) queries
• A query itself is the specific request issued to the DBMS
• Data quality is improved by ensuring accuracy, validity, and timeliness of data

Types of Databases:

• Single-user: Supports one user at a time (e.g., Microsoft Access)
• Multiuser: Supports multiple concurrent users

Workgroup vs Enterprise Databases:

• Workgroup: Supports fewer than 50 users or is used for a specific department
• Enterprise: Represents overall company data for present and future needs

Centralized vs Distributed Databases:

• Centralized: Stored and maintained at a single location, accessed via internet
• Distributed: Multiple databases connected and spread across physical locations

Other Database Classifications:

• Cloud: Created and maintained using cloud services (Microsoft Azure, Amazon AWS)
• General purpose: Data used in multiple disciplines (e.g., census)
• Discipline-specific: Data focused on specific subject areas, used mainly for research

Further Types of Databases

• Operational database: Designed for day-to-day company operations, also known as OLTP or production database
• Analytical database: Focuses on historical data and business metrics for strategic decision making
• Data warehouse: Stores historical, aggregated data optimized for decision support
• Online analytical processing (OLAP): Tools for advanced data analysis from data warehouses

Additional Database Categories:

• Business intelligence: Tools/processes to capture, integrate, store, analyze for business decisions
• Unstructured/raw: Data in its original format, not readily formatted
• Structured/formatted: Data formatted for storage, use, and information generation
• Semistructured: Data already partially processed

More Database Types:

• Extensible Markup Language (XML): Supports storage/management of semistructured XML data in textual format
• Social media: Enables "anywhere, anytime" human interactions
• NoSQL: A new generation of DBMS not based on the traditional relational model

Common Database Products:

• MS Access is used by a single user and provides data usage for centralized environments
• MS SQL Server may be be single-user or multi user that provides data usage for centralized or distributed environments
• IBM DB2 is multi user that provides data usage for centralized or distributed environments
• MySQL is multi user that provides data usage for centralized or distributed environments
• Oracle RDMS is multi user that provides data usage for centralized or distributed environments

Database Design

• Database design involves designing the database structure for storing and managing data

Database Structure

• Database structure is defined by how data is organized within it
• Tables are the fundamental blocks that organize data into rows and columns

File System Data Processing:

• Manual: Accomplished through file folders and filing cabinets
• Computerized: Data is tracked and reports are produced

Basic File Terminology:

• Data: Raw facts with little meaning unless organized
• Field: A character or group of characters with a specific meaning
• Record: A logically connected set of fields describing a person, place, or thing
• File: A collection of related records

Simple File Systems

• Sales department manages sales files
• Personnel departments mange employee files
• Customer information may be duplicated in different departments files

Problems with File Systems Data Processing:

• Lengthy development times due to extensive programming
• Difficulty of getting quick answers as each report requires a program
• Complex system administration
• Lack of security and data sharing
• Extensive programming for changes

Structural and Data Dependence:

• Access to a file is dependent on its structure
• Structural independence allows changes without affecting application access

Data Redundancy

• Storing the same basic data in different locations leading to poor data security
• Uncontrolled redundancy leads to data inconsistency, data integrity problems and data entry errors

Data Anomalies:

• Caused by redundancy, forcing field value changes in multiple locations
• Types of anomalies: Update, insertion and deletion

Database Systems

• They are an organization of hardware, software, application programs, people, procedures, and data
• It is built on components defining the collection, storage, management, and use of data
• These are structured database that uses less files

DBMS Functions:

• Data dictionary management: Stores metadata
• Data storage management: Creates/manages structures for data storage
• Data transformation/presentation: Transforms data to fit structures
• Security management: Enforces user security/privacy
• Multiuser access control: Manages concurrent access and ensures data integrity
• Backup/recovery management: Provides backup and data recovery
• Data integrity management: Enforces rules, minimizes redundancy, and maximizes consistency
• Database access languages: Provides a language to access data
• Communication interfaces: Accepts requests via different networks

Database Career Opportunities:

• Database Developer, who creates and maintains database-based applications with programming
• Database Designer, who defines systems design and database design with systems design
• Database Administrator, who performs database fundamentals and SQL courses skills
• Database Analyst, who has SQL, query optimization, data warehouses skills
• Database Architect, who has DBMS fundamentals, data modeling, SQL, hardware knowledge, etc, skills
• Database Consultant, who has Database fundamentals, data modeling skills
• Database Security Officer, who has DBMS fundamentals and database administration skills
• Cloud Computing Data Architect, who understands Internet technologies
• Data Scientist, who understands Data analysis skills