10.Oracle Data types

Ø  Columns has Data types

Ø  It Has Specific Storage format, Constraints And Valid Range

Several Data types

Some Commonly used data types are:

Ø  Character Data types

Ø  Numeric Data Types

Ø  Datetime Data Types

Ø  Rowid Data Types

Ø  LOBs(large objects)

Character Data Types

It Stores Character(Alphanumeric) Data In string.

      i.e...Letters, Numbers, Spaces, Symbols, and Punctuation are stored using      Character Data types

v  Commonly Used character Data types  is VARCHAR2

v  VARCHAR2 reduces space consumption

            create table EMP(  EMPNO NUMBER(3),

                                                 NAME  VARCHAR2(20),

                                                 DTE   DATE,

                                                 IMG   BLOB,

                                                    RID   RAW(10))

Numeric Data types

Ø  Stores Fixed and Floating Point Numbers, zero and infinity.

Ø  Commonly Used Number Data types

Ø  Does Not Store Leading  zeros

Ø  Format for a number data type is a number (p,s) where p is precision and s is the scale

Ø  Floating-point Numbers ,binary _float and Binary double are also Numeric datatypes

Datetime Data Types

Ø  It stores Date and Time

Ø  Stores Internally as Numbers

Ø  Stores fixed length Fields of 7 bytes each

Ø  Displays According to specified Format

Ø  Common  date Format is DD-MON-YY

TIMESTAMP DATA TYPES

Ø  Extension of the date data types

Ø  Stores Fractional seconds

Ø  Useful for Track Event Order

ROWID DATA TYPES

Ø  Stores Address of every row in the database

Ø  Physical rowid store address of row in heap organized tables

Ø  logical rowid  stores address of rows in index organized  tables

Ø  foreign rowid are identifiers in foreign tables

LOBs(Large objects)

Ø  Used to store Large objects

Ø  Mainly Used for Storing Images

Ø  It store and manipulate large blocks of unstructured data (such as text, graphic images, video clips, and sound waveforms) in binary or character format.

Ø  Commonly used LOB  datatypes are  BLOB  and CLOB

Ø  Blob Means  BINARY LARGE OBJECT where as CLOB as Character Large Objects

Ø  For storing image, voice, graphical we using Blob