## Tuesday, 31 December 2013

### How to generate random character strings in a range in Excel

How to generate Alpha-Numeric strings in a range in Excel
In Microsoft Excel , Sometimes you may need to generate random strings , such as different passwords , uniqued ids with Numeric or Alpha Numeric combinaiton.It can be done as :

1. To create a random 5-digit number between 10000 and 99999, use this formula:

=RANDBETWEEN(10000,99999)

Now press Enter key, a 5-digit number will be display in a cell, then select the cell and drag the fill handle across to the range that you want to contain this formula, a range of 5-digit numbers have been generated, see screenshots:

2. To create a random letter, use this formula:

=CHAR(RANDBETWEEN(65,90))

This formula can generate a random letter from a to z.

3. To create a Alpha-Numeric String:
If you need to create Alphanumeric Strings with special characters, you need to use & character to join letters and the letters.

See the following example how it is generationg Alpha Numeric string with speical character '-'
The following formula generates a Alpha Numeric String( 3 Alpha &"-"& 3Numeric&3 Alpha) of length 11.

=CHAR(RANDBETWEEN(65,90))&
CHAR(RANDBETWEEN(65,90))&
CHAR(RANDBETWEEN(65,90))&"-"&
RANDBETWEEN(1001,5000)&
CHAR(RANDBETWEEN(65,90))&
CHAR(RANDBETWEEN(65,90))&
CHAR(RANDBETWEEN(65,90))

The result would be as follows :

Thanks,
TAMATAM

## Thursday, 26 December 2013

### What is the Difference between Candidate Key, Alternate Key, and Composite Key

Explain Candidate Key, Alternate Key, and Composite Key

Candidate Key :
A Candidate Key is one that can uniquely identify each row of a table.Generally a candidate key becomes the Primary Key of the table.

Alternate Key:
If the table has more than one Candidate Key, one of them will become the Primary Key, and the rest are called Alternate Keys.

Composite Key :
A key formed by combining at least two or more columns is called Composite Key.