Mrs. Basma Alsadiqbalsadiq@itc.uob.bh

S40-1060

Database is a collection of records. It is an organized collection of information. There are many types of database.

Structured Query Language (SQL) is the language used to manipulate relational database

Structured Query Language (SQL) Standard query language for relational

databases Query: command to perform

operation on database object Create Modify View Delete

Data Definition Language (DDL) Used to create and modify the structure of

database objects Data Manipulation Language (DML)

Used to insert, update, delete, and view database data

Used to create and modify the structure of database objects CREATE ALTER DROP

DDL commands execute as soon as they are issued, and do not need to be explicitly saved

Used to insert, view, and modify database data INSERT UPDATE DELETE SELECT

DML commands need to be explicitly saved or rolled back COMMIT ROLLBACK

Transaction control commands

An Oracle database consists of multiple user accounts

Each user account owns database objects Tables Views Stored programs Etc.

Start Using SQL & SQL*PLUS

is a client terminal software allowing users to interact with Oracle server to manipulate data and data structures.

Creating tables is the first step in making your own database, and it follows the syntax:

CREATE TABLE tablename(

Column1 datatype(size),

Column2 datatype(size),

…..

);

Datatype Description

VARCHAR(n) Variable-length character data (n is the maximum number of characters)

CHAR(n) CHARACTER(n)

Fixed-length character data (n is the number of characters)

NUMERIC(p,s) DECIMAL(p,s)

Variable-length numeric data (p is the precision, s is the scale

INTInteger value

DATE Calendar date (DD-MMM-YYYY)

TIMEClock time (HH:MM:SS)

TIMESTAMP Date & time

CREATE TABLE student( ID Number(8), Name Varchar(15), GPA Decimal(3,2), Major Varchar(5), DOB Date);

If a table in the database is not needed any longer , then we can delete it using DROP TABLE command

Example:

Drop TABLE employee

Using ALTER TABLE command Syntax:

ALTER TABLE <table_name>

ADD <column_name> <datatype>(size)

Using ALTER TABLE command Syntax:ALTER TABLE <table_name>

Modify <column_name> <datatype>(size)

Using ALTER TABLE command Syntax:

ALTER TABLE <table_name>

DROP COLUMN <column_name>;

To change the name of a table, use the following statement.Syntax:

ALTER TABLE <table_name>

rename to <new-name>

To change the name of a table column, use RENAME statement.Syntax:

ALTER TABLE <table_name>

rename column <old-name> to <new-name>