type and like

Hi friends,

iam very much confused between the below 2 types of declaration.

can any one make me clear between the below following declations.

*************************************

1)

types:

var1 type mara-matnr.

data :

var2 type var1.

*************************************

2)

types :

var3 like mara-matnr.

data :

var4 type var3.

**************************************

Regards,

Priyanka.