What are the domains and data elements?

1)Domain consists of technical characterstics of a field.thay are data type and length.
Data element consists of field label and its length.Such AS:
DOMAINS : FORMAL DEFINITION OF THE DATA TYPES.THEY SET ATTRIBUTES SUCH AS DATA TYPE,LENGTH,RANGE. DATA ELEMENT : A FIELD IN R/3 SYSTEM IS A DATA ELEMENT.

2)Uses:
a)domains:
domains are the dictionary objects that are assigned with constants and data types

b)data elements:
data elements are dictionary objects that are assigned with the domains.
uses:

* data elements are used to create relation between tables.

* data elements are used to transfer the data from one R/3 to another R/3.

* to create search helps.