Data vs Information and DBMS

• Data comprises facts, observations, perceptions, numbers, characters, symbols and images.

Data vs Information

• Data refers to raw, unorganized facts that require processing to make them meaningful.
• Information is a set of data processed meaningfully per requirements, presented in context to be useful.
• Data lacks inherent purpose while information carries meaning derived from interpreting data.
• Data alone is insignificant, while information is significant by itself.
• Data is independent of information, but information relies on data.
• Data can be structured as tabular data, graphs, or data trees while information consists of language, ideas and thoughts based on the data.

Information

• Information improves data reliability and reduces uncertainty; lacking useless details.

Database Management System (DBMS)

• DBMS is a set of software used to define, store, manipulate, and control data in a database.
• Over 40 years, database technology has evolved from flat-file systems to relational and object-relational systems.
• A manual database is a collection of files stored in filing cabinets while a Computerized/Electronic database uses a database management system

Computerized vs Paper Based Database

• Computerized databases hold vast amounts of data while paper-based are limited by physical space
• Computerized databases allow for fast information retrieval compared to the manual search in paper-based
• Computerized databases allow easy search for specific criteria, unlike the manual look-up required for paper-based
• Computerized databases are easy to analyze while paper-based systems are difficult to analyze
• Computerized databases support sorting on multiple criteria while paper-based are difficult to sort by multiple criteria
• Computerised databases are easy to update while paper based are require manual update
• Computerized databases are safely stored while paper-based ones are easily lost
• Computerized databases offer password protection unlike the physical locking of paper based
• Computerized databases are easy to back-up relative to the cumbersome recreation/photocopying of paper-based, requiring additional space.

Evolution of Database Systems

• 1960: Charles Bachman designed the first DBMS system.
• 1970: Codd introduced IBM's Information Management System (IMS).
• 1976: Peter Chen defined the Entity-Relationship (ER) model.
• 1980: The relational model became a widely accepted component.
• 1985: Object-oriented DBMS developed.
• 1990s: Object-orientation incorporated into relational DBMS.
• 1991: Microsoft Access was released, a personal DBMS.
• 1995: First internet database applications emerged.
• 1997: XML was applied to database processing with vendors began integrating XML into DBMS products.
• Tedd Cood is the Father of Relational Databases (RDBMS).

Situations to Use a Database:

• Storing: Criminal records, student records, and patient history
• Tracking: Government records, income tax payments and drivers in violations

Data Models

• File-based (1960s)
• Hierarchical (1970s)
• Network (1970s)
• Relational (1980s)
• Entity-Relationship (1980s)
• Object-Oriented (1990s)
• Web-based (2000s) with NoSQL and NewSQL

Flat-File Database

• Flat-file databases store data in plain text without associated paths or folders.

Hierarchical Database

• A hierarchical database is a data model with data organized into a tree-like structure
• Data is stored as records connected through links.
• Each record is a collection of fields with only one value per field.
• Every child node (sub-folder) will have a single parent (folder or sub-folder).
• This creates a hierarchy

Network Database

• Network databases link multiple member records to multiple owner files.
• The model has an upside-down tree structure where member data is the branch linked to the owner.
• Network DBMS allows each record to have multiple parents/children for flexible relationships between entities.
• Charles Bachman introduced the network model in 1969, being computer network system-built and enhancing the hierarchical model.
• Examples of network databases: Integrated Data Store (IDS), IDMS, Raima Database Manager, TurboIMAGE, and Univac DMS-1100.

Relational Database

• The relational model of data was proposed by E. F. Codd in 1970 to manage relational databases with a relational database management system
• Many systems are designed use SQL for querying and maintaining the database.
• Multiple keys merge data to optimize occupied disk space

Object-Oriented Database (OOD)

• Object-oriented database works with objects, which in turn mirror what is used in object-oriented programming languages.
• Object-oriented databases treat everything as an object with various properties and procedures

Cloud Database

• A cloud database accesses and uses built in database services through a cloud platform
• Top cloud databases include: Amazon Web Service (AWS), Oracle Database and Microsoft Azure
• Google Cloud includes Cloud SQL, Cloud Spanner, and Bare Metal Solution, providing managed MySQL, PostgreSQL, and SQL Server databases.

Markup Languages

• XML stands for extensible markup language.
• Markup languages such as HTML use descriptive codes or tags.

DBMS (Database Management System)

• DBMS acts as a data librarian to oversee data transfer, allowing users to create, read, update, and delete data within the database.
• Leading database companies: Microsoft, IBM, and Oracle

Popular DBMS systems:

• MySQL
• Microsoft Access
• Oracle
• PostgreSQL
• dBASE
• FoxPro
• SQLite
• IBM DB2
• LibreOffice Base
• MariaDB
• Microsoft SQL Server etc.

Everyday usage of databases include:

• Online television streaming
• Social Gaming
• Personal cloud storage
• Sports
• Finances
• Government Organizations
• Social Media
• E-commerce
• Healthcare
• Weather
• Databases are used for ATMs to withdraw money and digital interactions
• Google’s search engine makes used a database called “Bigtable”

Advantages of DBMS:

• Reduces data redundancy by integrating files in a single database.
• High level data security by protected data and granting authorization
• Improves data integrity through unifying files in a single file for reducing data duplicity, and inconsistency.
• Accommodates multiple users to access the database without conflicts.
• Controls data redundancy and data consistency via data consistency.
• Data is stored in a single database so data becomes consistent compared to file processing systems.
• Data is safely shared between authorized users.
• Enforces data format/document standards.
• Unauthorized access to data is restricted.
• Tunability improves performance.

Disadvantages of DBMS:

• The DBMSs have advanced functionality make it a complex software for designers, developers, database administrators and end-users to understand,
• DBMS software occupies large disk space.
• DBMS Performance may not run as fast.
• Higher system vulnerability for centralised resources because all users rely on the availability of DBMS
• High of hardware/software cost and has maintenance cost

Use of DBMS by sector:

• Banking: storing customer information, account activities, payments, deposits, loans, etc.
• Airline: storing reservations and schedules.
• Universities: storing student information, course registrations, colleges and grades.
• Telecommunication: storing call records, monthly bills and maintaining balances.
• Finance: storing information about stock, sales, financial instruments, purchases like stocks.
• Sales: storing customer information, product information and sales data.
• Manufacturing: managing supply chain and tracking item production, track inventories in warehouses.
• HR- storing Employee salaries, deductions; generating paychecks, etc.

Characteristics of DBMS:

• Provides security and removes redundancy
• Self-describing nature of a database system
• Insulation between programs and data abstraction
• Support of multiple views of the data
• Sharing of data and multiuser transaction processing
• Management software forms entity relationships, with tables.
• Follows the ACID concept (Atomicity, Consistency, Isolation, and Durability).
• Supports multi-user environment so multiple users can access and manipulate data in parallel.

ACID Concepts

• ACID ensures that data transactions in a DBMS are reliable.
• Atomicity: In the event that something fails that an entire transaction takes place or does not happen at all.
• Consistency: Database consistent before and after the transaction.
• Isolation: Multiple Transactions occur independently without interference.
• Durability: Database changes from successful transactions still occur even if the a system failure occurs

ACID Example: Transfer of funds

• Transaction: This incorporates an operation to withdraw money from checking, operation to deposit those funds to savings, etc.
• Atomicity: All steps need to be fully completed or none at all. This guarantees no steps are left “hanging”.
• Consistency: The end and start states have to be valid, to ensure no money is created during money movement. If a step fails, it would revert
• Isolation: Concurrent transactions cannot interfere with each other.
• Durability: Once the money has been moved, account balances need to be recorded

Database Users

• Application Programmers: Application programmers use DML queries inside code to make data manageable
• Sophisticated Users: The sophisticated users directly enter SQL queries without the help of application software.
• Specialised users are responsible for writing specialized database application programs.
• StandAlone users use the ready-made databases and graphical interfaces with menus icons and buttons.
• Native users use graphical user interfaces provided as part of the system, like login systems.
• Database administrator: Maintains databases through things like: maintaining integrity, limiting redundancy, ensuring data normalization

Acronyms

• DBMS - DATABASE MANAGEMENT SYSTEM
• IBM - INTERNATIONAL BUSINESS MACHINES
• CODASYL - CONFERENCE ON DATA SYSTEMS LANGUAGES
• DBA - DATABASE ADMINISTRATOR
• XML - EXTENSIBLE MARKUP LANGUAGE
• HTML - HYPERTEXT MARKUP LANGUAGE
• SQL - STRUCTURED QUERY LANGUAGE
• RDBMS - RELATIONAL DATABASE MANAGEMENT SYSTEMS
• OODBS - OBJECT-ORIENTED DATABASE MANAGEMENT SYSTEM

When not to Use DBMS

• Use excel CSV flat files if a the budget and expertise to operate a DBMS are not available

Summary of Database Points

• DBMS = collection of related data that represent some aspect of the real world
• DBMS = software for storing and retrieving users' data by considering appropriate security
• DBMS Provides security and removes redundancy and provides many advantages over tradition Flat File management Systems
• 4 DBMS types are 1) Hierarchical 2) Network 3) Relational 4) Object-Oriented
• DBMS serves as an efficient handler to balance the needs of multiple applications using the same data with security measures
• Hardware/software for DBMS is expensive
• Users include End-Users, Application Programmers, and Database Administrators
• DBMS is widely used in Banking, Airlines, Telecommunication, Finance, and other industries