!Domain 
VARCHARnn is an [application domain|DOMAIN] which imparts the following characteristics::
* Oracle data type is VARCHAR2 with a length of nn

!Data Type
VARCHARnn is an [Oracle data type] that identifies the field in the data base as holding alphanumeric (characters and numbers) values with a variable length not to exceed the number indicated.  For example, a field defined as VARCHAR30 may hold a value which has a length up to 30 characters long, but only actually uses as much space as needed on the disk.  If the value is unspecified (length = 0) then this is known as [NULL] value.