refrential nothing but forgein key

it show referance to another location with accuracy.

Referential integrity
Referential integrity in a relational database is 
consistency between coupled tables. Referential integrity 
is usually enforced by the combination of a primary key or 
candidate key (alternate key) and a foreign key. For 
referential integrity to hold, any field in a table that is 
declared a foreign key can contain only values from a 
parent table's primary key or a candidate key. For 
instance, deleting a record that contains a value referred 
to by a foreign key in another table would break 
referential integrity. A relational database management 
system (RDBMS) enforces referential integrity, normally 
either by deleting the foreign key rows as well to maintain 
integrity, or by returning an error and not performing the 
delete. Which method is used would be determined by the 
referential integrity constraint, as defined in the data 
dictionary.