maheshhadawale

 Profile Answers by maheshhadawale 

• Feb 19th, 2006

 

Primary Key is a much similar to unique key. Only difference is that unique key can be null but primary key can not be null. Primary key is used to avoid duplication of data.

A primary key consists of more than one column. Also known as a concatenated key or Aggregate Key. it is also called as composite key.

Example for varchar & varchar2()

Emp_name varchar(10) -  if you enter value less than 10 then remaining space can not be deleted. it used total 10 spaces.

Emp_name varchar2(10) - if you enter value less than 10 then remaining space is automatically deleted.

vishu7vishu

 Profile Answers by vishu7vishu 

• Feb 20th, 2007

 

Well, tht's not a difference between Varchar & Varchar2, but rather beween Char & Varchar / Varchar2.

Varchar & Varchar2 are just the synonyms and can be used in place of each-other.

yuvarajan2000

 Profile Answers by yuvarajan2000 

• Apr 24th, 2007

 

Varchar and Varchar2 is different.
Varchar and varchar2 store is 2000 char.

varchar2 size is automatically reduce. It will take on using char size based.

shravanam

 Profile Answers by shravanam Questions by shravanam

• Oct 25th, 2007

 

In varchar u can store upto 2000 bytes
In varchar2 u can store upto 4000 bytes
In Oracle  even if u declare a variable with varchar it takes varchar2 into consideration and creates that variable with varchar2