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Introduction to Oracle SQL

What is Data?

Data is a collection of small volume of facts and figures representing information.

Examples

  • Name
  • Age
  • Gender
  • Phone Number
  • Email ID

What is a Database?

A Database is a collection of a large volume of facts and figures stored in an organized manner.

Examples

  • University Details
  • Hospital Details
  • Bank Details
  • Employee Details

Management of Facts and Figures

The main objectives of data management are:

  • Store data permanently
  • Retrieve data efficiently

Data Management in Olden Days

In earlier days, information was stored manually using ledgers.

Managing large volumes of data manually was:

  • Time consuming
  • Difficult to maintain
  • Difficult to retrieve quickly
  • More prone to errors

Data Management using Programming Languages

Programming languages such as:

  • C
  • Java

can store small amounts of data using variables.

Example:

String name = "Basha";
int age = 23;
String gender = "Male";
String branch = "ECE";
int studentId = 458;
int percentage = 93;

Limitation

Programming languages are effective for storing small amounts of data but become difficult when handling large volumes of information because:

  • Every value requires a variable declaration
  • Data types must be specified
  • Initialization is required for each variable

DBMS (Database Management System)

DBMS was introduced to manage large amounts of data efficiently.

DBMS stands for:

D – Data
B – Base
M – Management
S – System

Advantages of DBMS

  • Stores large volumes of data
  • Reduces redundancy
  • Provides data security
  • Supports efficient data retrieval
  • Maintains data consistency

Popular Databases

Some widely used database systems are:

  1. Oracle
  2. MySQL
  3. Sybase
  4. DB2

History of Oracle

  • In 1977, Larry Ellison, Bob Miner, and Ed Oates founded Software Development Laboratory (SDL).
  • In 1979, SDL was renamed to Relational Software Inc. (RSI).
  • In 1982, RSI became Oracle Systems Corporation (OSC).
  • In 1995, OSC was renamed Oracle Corporation.

Today, it is popularly known as Oracle.

Oracle Versions

Version Year
Oracle 1 1978
Oracle 2 1979
Oracle 3 1983
Oracle 4 1984
Oracle 5 1985
Oracle 6 1988
Oracle 7 1992
Oracle 8 1997
Oracle 8i 1999
Oracle 9i 2001
Oracle 10g 2004
Oracle 11g 2007
Oracle 12c 2013
Oracle 18c 2018
Oracle 19c 2019

What is SQL?

SQL stands for Structured Query Language.

  • Structured → Data is stored in tables.
  • Query → Used to ask questions from the database.
  • Language → Used to communicate with the database.

History of SQL

  • SQL was developed in 1970.
  • Invented by Raymond Boyce and Donald Chamberlin.
  • SQL is also known as SEQUEL (Structured English Query Language).

Structure of a Table

A table consists of:

Rows

Rows are also called:

  • Tuples
  • Records

Columns

Columns are also called:

  • Attributes
  • Fields

A table is also known as a Relation.

Rules for Storing Data in a Database

  1. Create a table.
  2. Define columns with data types.
  3. Insert records into the table.

Creating a Table

Syntax

CREATE TABLE table_name(
    column_name1 datatype,
    column_name2 datatype,
    column_name3 datatype
);

Example

CREATE TABLE student(
    name VARCHAR2(16),
    age NUMBER,
    gender CHAR(6),
    branch VARCHAR2(16),
    id INT,
    marks INT
);

Inserting Data into a Table

Syntax

INSERT INTO table_name
VALUES(value1, value2, value3);

Example

INSERT INTO student
VALUES(
'Shaik Mahaboob Basha',
23,
'Male',
'ECE',
458,
93
);
INSERT INTO table_name (column_name1, column_name2, column_name3) VALUES(value1, value2, value3);

Example

INSERT INTO student (name, age)
VALUES(
'Shaik Mahaboob Basha',
23);

Important Note

In SQL, every statement ends with a semicolon (;).

The semicolon indicates the end of a SQL statement.

Repository Goal ⭐

This file provides the fundamental concepts of Oracle SQL including Data, Database, DBMS, Oracle History, SQL Basics, Table Structure, and Database Creation concepts for beginners and interview preparation.

Happy Learning and Keep Practicing SQL!