<s>
Polymorphic	B-Application
association	I-Application
is	O
a	O
term	O
used	O
in	O
discussions	O
of	O
Object-Relational	B-General_Concept
Mapping	I-General_Concept
with	O
respect	O
to	O
the	O
problem	O
of	O
representing	O
in	O
the	O
relational	B-Application
database	I-Application
domain	O
,	O
a	O
relationship	O
from	O
one	O
class	O
to	O
multiple	O
classes	O
.	O
</s>
<s>
In	O
statically	O
typed	O
languages	O
such	O
as	O
Java	B-Language
these	O
multiple	O
classes	O
are	O
subclasses	O
of	O
the	O
same	O
superclass	O
.	O
</s>
<s>
In	O
languages	O
with	O
duck	B-Application
typing	I-Application
,	O
such	O
as	O
Ruby	B-Language
,	O
this	O
is	O
not	O
necessarily	O
the	O
case	O
.	O
</s>
