Introduction to Databases

INTRODUCTION

A database is a systematic collection of data. They support electronic storage and manipulation of data. Databases make data management easy.

Database is a collection of interrelated data which helps in the efficient retrieval, insertion, and deletion of data from the database and organizes the data in the form of tables, views, schemas, reports, etc. For Example, a university database organizes the data about students, faculty, admin staff, etc. which helps in the efficient retrieval, insertion, and deletion of data from it.

A Database Management System (DBMS) is a software system that is designed to manage and organize data in a structured manner. It allows users to create, modify, and query a database, as well as manage the security and access controls for that database.

HISTORY OF DATABASES

Here, are the important landmarks from the history:

- 1960: 2 models were in use when the concept of computerized DBMS started.Models used then CODASYL (N/W MODEL) and IMS (IBM’s hierarchical model). SABRE system by IBM was designed to help American Airlines manage reservations data.

- 1969: IBM introduced its first-ever mainframe machine as System/360.

- 1970-72: A computer scientist from IBM named E.F. Codd published an academic paper titled, A Relational Model of Data for Large Shared Banks. That paper introduced a new way to model data that was Entity-relationship model.

- 1976: ERD also known as entity-relationship diagrams came into play. These were proposed by P. Chen. They are also known as the conceptual models which focused more on the data application rather than logical tabular structure.

- 1980s: SQL became the standard query language. RDBMS was widely popular and DB2 became a flagship product by IBM. Later on, the introduction of IBM PCs further resulted in several new DB companies and products such as RBASE 5000 and RIM, PARADOX

- Early 90s: post DB industry shakeout, surviving companies sold their products as high prices. Meanwhile, new client tools for developing applications were released. These included Oracle Developer, VB and PowerBuilder. ODBC prototypes and Excel/Access were also developed within the same timeframe.

- The Mid 90s: Internet became popular which caused the exponential growth of the DB industry. More people with average desktops started using client/server systems for legal data.

- Late 90s: investment in online business resulted in internet DB connectors like FrontPage, Active Server Pages, Java Servlets, Dream Weaver, Oracle Developer 2000 and Enterprise Java Beans. Use of Apache, MySQL, and other systems introduced open-source solutions to the Internet. Gradually, online transaction processing and analytic processing became popular.

- The 2000s: DB applications were not affected by the decline of the internet industry. Interactive applications for PDAs, point-of-sale transactions and consolidation of vendors were developed.

- Present: Currently, Microsoft, Oracle, and IBM are the leading companies for Database Systems.

TWO MAJOR TYPES/CATEGORIES OF DATABASES

- Relational or Sequence Databases 
    - RDBMS(Relational Database Management System)
    - This type of database defines database relationships in the form of tables. 
   
   Examples of RDBMS :
	o	Microsoft SQL Server
	o	Oracle
	o	MySQL
	o	DB2
	o	Sybase


- Non-relational or Non-sequence or No-SQL (aka "not only SQL") Databases
    - NoSQL database is used for large sets of distributed data. 
    - This type of computers database is very efficient in analyzing large-size 
unstructured data.
   
   Examples of No-SQL Databases :
	o	MongoDB
	o	CouchDB
	o	Neo4J
	o	Cassandra
	o	Amazon DynamoDB
	o	Azure Cosmos DB