<s>
The	O
use	O
of	O
search	B-Application
engine	I-Application
technology	I-Application
is	O
the	O
main	O
integration	O
component	O
in	O
an	O
information	O
system	O
.	O
</s>
<s>
In	O
a	O
traditional	O
business	O
environment	O
the	O
architectural	B-Architecture
layer	I-Architecture
usually	O
occupied	O
by	O
a	O
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
(	O
RDBMS	O
)	O
is	O
supplemented	O
or	O
replaced	O
with	O
a	O
search	O
engine	O
or	O
the	O
indexing	O
technology	O
used	O
to	O
build	O
search	O
engines	O
.	O
</s>
<s>
Queries	O
for	O
information	O
which	O
would	O
usually	O
be	O
performed	O
using	O
Structured	B-Language
Query	I-Language
Language	I-Language
(	O
SQL	B-Language
)	O
are	O
replaced	O
by	O
keyword	O
or	O
fielded	O
(	O
or	O
field-enabled	O
)	O
searches	O
for	O
structured	O
,	O
semi-structured	B-General_Concept
,	O
or	O
unstructured	O
data	O
.	O
</s>
<s>
In	O
a	O
typical	O
multi-tier	B-Operating_System
or	O
N	B-Operating_System
tier	I-Operating_System
architecture	I-Operating_System
information	O
is	O
maintained	O
in	O
a	O
data	O
tier	B-Operating_System
where	O
it	O
can	O
be	O
stored	O
and	O
retrieved	O
from	O
a	O
database	O
or	O
file	O
system	O
.	O
</s>
<s>
The	O
data	O
tier	B-Operating_System
is	O
queried	O
by	O
the	O
logic	O
or	O
business	O
tier	B-Operating_System
when	O
information	O
is	O
needed	O
using	O
a	O
data	O
retrieval	O
language	O
like	O
SQL	B-Language
.	O
</s>
<s>
In	O
a	O
search-oriented	B-Architecture
architecture	I-Architecture
the	O
data	O
tier	B-Operating_System
may	O
be	O
replaced	O
or	O
placed	O
behind	O
another	O
tier	B-Operating_System
which	O
contains	O
a	O
search	O
engine	O
and	O
search	O
engine	O
index	O
which	O
is	O
queried	O
instead	O
of	O
the	O
database	O
management	O
system	O
.	O
</s>
<s>
Queries	O
from	O
the	O
business	O
tier	B-Operating_System
are	O
made	O
in	O
the	O
search	O
engine	O
query	O
language	O
instead	O
of	O
SQL	B-Language
.	O
</s>
<s>
The	O
search	O
engine	O
itself	O
crawls	O
the	O
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
in	O
addition	O
to	O
other	O
traditional	O
data	O
sources	O
such	O
as	O
web	O
pages	O
or	O
traditional	O
file	O
systems	O
and	O
consolidates	O
the	O
results	O
when	O
queried	O
.	O
</s>
<s>
The	O
benefit	O
of	O
adding	O
a	O
search	O
layer	O
to	O
the	O
architecture	O
stack	O
is	O
rapid	O
response	O
time	O
large	O
dynamic	O
datasets	O
made	O
possible	O
by	O
search	O
indexing	O
technology	O
such	O
as	O
an	O
inverted	B-Algorithm
index	I-Algorithm
.	O
</s>
