A Data Definition and Mapping Language
A data definition language i sa declarative
computer language for specifying data structures. 
 Most data definition languages concentrate on the declaration
of logical data structures with little 
concern for how these structures are physically realized
on a computer system.  However, the need for 
data definition languages which describe both the logical
and physical aspects of data is increasingly 
apparent.  Such languages will be a key systems, as well
as in advanced data management systems and distributed 
data bases.  This paper reviews past work in the data
definition language for describing both logical 
and physical aspects of data.  Applications of these
"generalized" data definition languages are also 
discussed.
CACM December, 1973
Sibley, E. H.
Taylor, R. W.
