<s>
In	O
computer	O
software	O
,	O
business	B-Architecture
logic	I-Architecture
or	O
domain	B-Architecture
logic	I-Architecture
is	O
the	O
part	O
of	O
the	O
program	O
that	O
encodes	O
the	O
real-world	O
business	O
rules	O
that	O
determine	O
how	O
data	O
can	O
be	O
created	B-General_Concept
,	I-General_Concept
stored	I-General_Concept
,	I-General_Concept
and	I-General_Concept
changed	I-General_Concept
.	O
</s>
<s>
It	O
is	O
contrasted	O
with	O
the	O
remainder	O
of	O
the	O
software	O
that	O
might	O
be	O
concerned	O
with	O
lower-level	O
details	O
of	O
managing	O
a	O
database	O
or	O
displaying	O
the	O
user	B-Application
interface	I-Application
,	O
system	O
infrastructure	O
,	O
or	O
generally	O
connecting	O
various	O
parts	O
of	O
the	O
program	O
.	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
:	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
comprises	O
:	O
</s>
<s>
Workflows	B-Operating_System
that	O
are	O
the	O
ordered	O
tasks	O
of	O
passing	O
documents	O
or	O
data	O
from	O
one	O
participant	O
(	O
a	O
person	O
or	O
a	O
software	O
system	O
)	O
to	O
another	O
.	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
should	O
be	O
distinguished	O
from	O
business	O
rules	O
.	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
is	O
the	O
portion	O
of	O
an	O
enterprise	O
system	O
which	O
determines	O
how	O
data	O
is	O
transformed	O
or	O
calculated	O
,	O
and	O
how	O
it	O
is	O
routed	O
to	O
people	O
or	O
software	O
(	O
workflow	B-Operating_System
)	O
.	O
</s>
<s>
Anything	O
that	O
is	O
a	O
process	O
or	O
procedure	O
is	O
business	B-Architecture
logic	I-Architecture
,	O
and	O
anything	O
that	O
is	O
neither	O
a	O
process	O
nor	O
a	O
procedure	O
is	O
a	O
business	O
rule	O
.	O
</s>
<s>
Welcoming	O
a	O
new	O
visitor	O
is	O
a	O
process	O
(	O
workflow	B-Operating_System
)	O
consisting	O
of	O
steps	O
to	O
be	O
taken	O
,	O
whereas	O
saying	O
every	O
new	O
visitor	O
must	O
be	O
welcomed	O
is	O
a	O
business	O
rule	O
.	O
</s>
<s>
Further	O
,	O
business	B-Architecture
logic	I-Architecture
is	O
procedural	O
whereas	O
business	O
rules	O
are	O
declarative	O
.	O
</s>
<s>
The	O
business	B-Architecture
logic	I-Architecture
of	O
the	O
website	O
might	O
include	O
a	O
workflow	B-Operating_System
such	O
as	O
:	O
</s>
<s>
The	O
web	O
site	O
software	O
also	O
contains	O
other	O
code	O
which	O
is	O
not	O
considered	O
part	O
of	O
business	B-Architecture
logic	I-Architecture
nor	O
business	O
rules	O
:	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
could	O
be	O
anywhere	O
in	O
a	O
program	O
.	O
</s>
<s>
For	O
example	O
,	O
given	O
a	O
certain	O
format	O
for	O
an	O
address	O
,	O
a	O
database	O
table	O
could	O
be	O
created	O
which	O
has	O
columns	O
that	O
correspond	O
exactly	O
to	O
the	O
fields	O
specified	O
in	O
the	O
business	B-Architecture
logic	I-Architecture
,	O
and	O
type	O
checks	O
added	O
to	O
make	O
sure	O
that	O
no	O
invalid	O
data	O
is	O
added	O
.	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
often	O
changes	O
.	O
</s>
<s>
Thus	O
it	O
is	O
often	O
seen	O
as	O
desirable	O
to	O
make	O
the	O
code	O
that	O
implements	O
the	O
business	B-Architecture
logic	I-Architecture
relatively	O
isolated	O
,	O
or	O
loosely	B-Application
coupled	I-Application
.	O
</s>
<s>
This	O
makes	O
it	O
more	O
likely	O
that	O
changes	O
to	O
business	B-Architecture
logic	I-Architecture
will	O
require	O
a	O
small	O
set	O
of	O
code	O
changes	O
,	O
in	O
only	O
one	O
part	O
of	O
the	O
code	O
.	O
</s>
<s>
A	O
multitier	B-Operating_System
architecture	I-Operating_System
formalizes	O
this	O
decoupling	O
by	O
creating	O
a	O
business	B-Architecture
logic	I-Architecture
layer	I-Architecture
which	O
is	O
separate	O
from	O
other	O
tiers	B-Operating_System
or	O
layers	O
,	O
such	O
as	O
the	O
data	B-Application
access	I-Application
layer	I-Application
or	O
service	B-Protocol
layer	I-Protocol
.	O
</s>
<s>
For	O
example	O
,	O
in	O
a	O
model	O
–	O
view	O
–	O
controller	O
paradigm	O
,	O
the	O
controller	O
and	O
view	O
layers	O
might	O
be	O
made	O
as	O
small	O
as	O
possible	O
,	O
with	O
all	O
the	O
business	B-Architecture
logic	I-Architecture
concentrated	O
in	O
the	O
model	O
.	O
</s>
<s>
For	O
example	O
,	O
with	O
relatively	O
simple	O
business	B-General_Concept
entities	I-General_Concept
,	O
a	O
generic	O
view	O
and	O
controller	O
could	O
access	O
database	O
objects	O
which	O
themselves	O
contain	O
all	O
the	O
relevant	O
business	B-Architecture
logic	I-Architecture
about	O
what	O
formats	O
they	O
accept	O
and	O
what	O
changes	O
are	O
possible	O
(	O
known	O
as	O
the	O
database	B-General_Concept
model	I-General_Concept
)	O
.	O
</s>
<s>
Some	O
tiered	O
schemes	O
use	O
either	O
a	O
distinct	O
application	B-Application
layer	I-Application
or	O
a	O
service	B-Protocol
layer	I-Protocol
,	O
or	O
consider	O
the	O
business	B-Architecture
logic	I-Architecture
layer	I-Architecture
to	O
be	O
the	O
same	O
as	O
one	O
of	O
those	O
.	O
</s>
<s>
Business	B-Architecture
logic	I-Architecture
can	O
be	O
extracted	O
from	O
procedural	O
code	O
using	O
a	O
business	B-Application
rule	I-Application
management	I-Application
system	I-Application
(	O
BRMS	B-Application
)	O
.	O
</s>
<s>
The	O
business	B-Application
rules	I-Application
approach	I-Application
of	O
software	O
development	O
uses	O
BRMSs	O
and	O
enforces	O
a	O
very	O
strong	O
separation	O
of	O
business	B-Architecture
logic	I-Architecture
from	O
other	O
code	O
.	O
</s>
<s>
User	B-Application
interface	I-Application
management	I-Application
systems	I-Application
are	O
another	O
technology	O
used	O
to	O
enforce	O
a	O
strong	O
separation	O
between	O
business	B-Architecture
logic	I-Architecture
and	O
other	O
code	O
.	O
</s>
<s>
The	O
magic	O
pushbutton	O
is	O
considered	O
an	O
"	O
anti-pattern	O
"	O
:	O
a	O
technique	O
that	O
in	O
this	O
case	O
creates	O
undesirable	O
constraints	O
which	O
make	O
it	O
difficult	O
to	O
code	O
business	B-Architecture
logic	I-Architecture
in	O
an	O
easy-to-maintain	O
way	O
.	O
</s>
<s>
A	O
domain	B-Application
model	I-Application
is	O
an	O
abstract	O
representation	O
of	O
the	O
data	O
storage	O
types	O
required	O
by	O
business	O
rules	O
.	O
</s>
