<s>
In	O
computing	O
,	O
a	O
data	O
warehouse	O
(	O
DW	O
or	O
DWH	O
)	O
,	O
also	O
known	O
as	O
an	O
enterprise	O
data	O
warehouse	O
(	O
EDW	O
)	O
,	O
is	O
a	O
system	O
used	O
for	O
reporting	O
and	O
data	B-General_Concept
analysis	I-General_Concept
and	O
is	O
considered	O
a	O
core	O
component	O
of	O
business	B-General_Concept
intelligence	I-General_Concept
.	O
</s>
<s>
Data	O
warehouses	O
are	O
central	O
repositories	B-General_Concept
of	O
integrated	O
data	O
from	O
one	O
or	O
more	O
disparate	O
sources	O
.	O
</s>
<s>
The	O
data	O
stored	O
in	O
the	O
warehouse	O
is	O
uploaded	B-Application
from	O
the	O
operational	O
systems	O
(	O
such	O
as	O
marketing	O
or	O
sales	O
)	O
.	O
</s>
<s>
Extract	O
,	O
transform	O
,	O
load	O
(	O
ETL	O
)	O
and	O
extract	B-General_Concept
,	I-General_Concept
load	I-General_Concept
,	I-General_Concept
transform	I-General_Concept
(	O
ELT	B-General_Concept
)	O
are	O
the	O
two	O
main	O
approaches	O
used	O
to	O
build	O
a	O
data	O
warehouse	O
system	O
.	O
</s>
<s>
The	O
typical	O
extract	O
,	O
transform	O
,	O
load	O
(	O
ETL	O
)	O
-based	O
data	O
warehouse	O
uses	O
staging	O
,	O
data	B-General_Concept
integration	I-General_Concept
,	O
and	O
access	O
layers	O
to	O
house	O
its	O
key	O
functions	O
.	O
</s>
<s>
The	O
combination	O
of	O
facts	O
and	O
dimensions	O
is	O
sometimes	O
called	O
a	O
star	B-Application
schema	I-Application
.	O
</s>
<s>
The	O
main	O
source	O
of	O
the	O
data	O
is	O
cleansed	O
,	O
transformed	O
,	O
catalogued	O
,	O
and	O
made	O
available	O
for	O
use	O
by	O
managers	O
and	O
other	O
business	O
professionals	O
for	O
data	B-Application
mining	I-Application
,	O
online	B-Application
analytical	I-Application
processing	I-Application
,	O
market	O
research	O
and	O
decision	B-Application
support	I-Application
.	O
</s>
<s>
However	O
,	O
the	O
means	O
to	O
retrieve	O
and	O
analyze	B-General_Concept
data	I-General_Concept
,	O
to	O
extract	O
,	O
transform	O
,	O
and	O
load	O
data	O
,	O
and	O
to	O
manage	O
the	O
data	B-Application
dictionary	I-Application
are	O
also	O
considered	O
essential	O
components	O
of	O
a	O
data	O
warehousing	O
system	O
.	O
</s>
<s>
Thus	O
,	O
an	O
expanded	O
definition	O
for	O
data	O
warehousing	O
includes	O
business	B-Application
intelligence	I-Application
tools	I-Application
,	O
tools	O
to	O
extract	O
,	O
transform	O
,	O
and	O
load	O
data	O
into	O
the	O
repository	B-General_Concept
,	O
and	O
tools	O
to	O
manage	O
and	O
retrieve	O
metadata	O
.	O
</s>
<s>
ELT-based	O
data	O
warehousing	O
gets	O
rid	O
of	O
a	O
separate	O
ETL	O
tool	O
for	O
data	O
transformation	O
.	O
</s>
<s>
Integrate	O
data	O
from	O
multiple	O
sources	O
into	O
a	O
single	O
database	O
and	O
data	B-Application
model	I-Application
.	O
</s>
<s>
Mitigate	O
the	O
problem	O
of	O
database	O
isolation	O
level	O
lock	O
contention	O
in	O
transaction	B-General_Concept
processing	I-General_Concept
systems	O
caused	O
by	O
attempts	O
to	O
run	O
large	O
,	O
long-running	O
analysis	O
queries	O
in	O
transaction	B-General_Concept
processing	I-General_Concept
databases	O
.	O
</s>
<s>
Provide	O
a	O
single	O
common	B-Application
data	I-Application
model	I-Application
for	O
all	O
data	O
of	O
interest	O
regardless	O
of	O
the	O
data	O
's	O
source	O
.	O
</s>
<s>
Data	B-General_Concept
integration	I-General_Concept
technology	O
and	O
processes	O
that	O
are	O
needed	O
to	O
prepare	O
the	O
data	O
for	O
use	O
;	O
</s>
<s>
Different	O
architectures	O
for	O
storing	O
data	O
in	O
an	O
organization	O
's	O
data	O
warehouse	O
or	O
data	B-General_Concept
marts	I-General_Concept
;	O
</s>
<s>
In	O
regards	O
to	O
source	O
systems	O
listed	O
above	O
,	O
R	O
.	O
Kelly	O
Rainer	O
states	O
,	O
"	O
A	O
common	O
source	O
for	O
the	O
data	O
in	O
data	O
warehouses	O
is	O
the	O
company	O
's	O
operational	O
databases	O
,	O
which	O
can	O
be	O
relational	B-Application
databases	I-Application
"	O
.	O
</s>
<s>
Regarding	O
data	B-General_Concept
integration	I-General_Concept
,	O
Rainer	O
states	O
,	O
"	O
It	O
is	O
necessary	O
to	O
extract	O
data	O
from	O
source	O
systems	O
,	O
transform	O
them	O
,	O
and	O
load	O
them	O
into	O
a	O
data	B-General_Concept
mart	I-General_Concept
or	O
warehouse	O
"	O
.	O
</s>
<s>
Rainer	O
discusses	O
storing	O
data	O
in	O
an	O
organization	O
's	O
data	O
warehouse	O
or	O
data	B-General_Concept
marts	I-General_Concept
.	O
</s>
<s>
A	O
"	O
data	O
warehouse	O
"	O
is	O
a	O
repository	B-General_Concept
of	O
historical	O
data	O
that	O
is	O
organized	O
by	O
the	O
subject	O
to	O
support	O
decision-makers	O
in	O
the	O
organization	O
.	O
</s>
<s>
Once	O
data	O
is	O
stored	O
in	O
a	O
data	B-General_Concept
mart	I-General_Concept
or	O
warehouse	O
,	O
it	O
can	O
be	O
accessed	O
.	O
</s>
<s>
A	O
data	B-General_Concept
mart	I-General_Concept
is	O
a	O
simple	O
form	O
of	O
a	O
data	O
warehouse	O
that	O
is	O
focused	O
on	O
a	O
single	O
subject	O
(	O
or	O
functional	O
area	O
)	O
,	O
hence	O
they	O
draw	O
data	O
from	O
a	O
limited	O
number	O
of	O
sources	O
such	O
as	O
sales	O
,	O
finance	O
or	O
marketing	O
.	O
</s>
<s>
Data	B-General_Concept
marts	I-General_Concept
are	O
often	O
built	O
and	O
controlled	O
by	O
a	O
single	O
department	O
within	O
an	O
organization	O
.	O
</s>
<s>
Given	O
that	O
data	B-General_Concept
marts	I-General_Concept
generally	O
cover	O
only	O
a	O
subset	O
of	O
the	O
data	O
contained	O
in	O
a	O
data	O
warehouse	O
,	O
they	O
are	O
often	O
easier	O
and	O
faster	O
to	O
implement	O
.	O
</s>
<s>
Types	O
of	O
data	B-General_Concept
marts	I-General_Concept
include	O
dependent	O
,	O
independent	O
,	O
and	O
hybrid	O
data	B-General_Concept
marts	I-General_Concept
.	O
</s>
<s>
Online	B-Application
analytical	I-Application
processing	I-Application
(	O
OLAP	B-Application
)	O
is	O
characterized	O
by	O
a	O
relatively	O
low	O
volume	O
of	O
transactions	O
.	O
</s>
<s>
For	O
OLAP	B-Application
systems	O
,	O
response	O
time	O
is	O
an	O
effective	O
measure	O
.	O
</s>
<s>
OLAP	B-Application
applications	O
are	O
widely	O
used	O
by	O
Data	B-Application
Mining	I-Application
techniques	O
.	O
</s>
<s>
OLAP	B-Application
databases	O
store	O
aggregated	O
,	O
historical	O
data	O
in	O
multi-dimensional	O
schemas	O
(	O
usually	O
star	B-Application
schemas	I-Application
)	O
.	O
</s>
<s>
OLAP	B-Application
systems	O
typically	O
have	O
a	O
data	O
latency	O
of	O
a	O
few	O
hours	O
,	O
as	O
opposed	O
to	O
data	B-General_Concept
marts	I-General_Concept
,	O
where	O
latency	O
is	O
expected	O
to	O
be	O
closer	O
to	O
one	O
day	O
.	O
</s>
<s>
The	O
OLAP	B-Application
approach	O
is	O
used	O
to	O
analyze	O
multidimensional	O
data	O
from	O
multiple	O
sources	O
and	O
perspectives	O
.	O
</s>
<s>
The	O
three	O
basic	O
operations	O
in	O
OLAP	B-Application
are	O
Roll-up	O
(	O
Consolidation	O
)	O
,	O
Drill-down	O
,	O
and	O
Slicing	O
&	O
Dicing	O
.	O
</s>
<s>
Online	B-General_Concept
transaction	I-General_Concept
processing	I-General_Concept
(	O
OLTP	B-General_Concept
)	O
is	O
characterized	O
by	O
a	O
large	O
number	O
of	O
short	O
on-line	O
transactions	O
(	O
INSERT	O
,	O
UPDATE	O
,	O
DELETE	O
)	O
.	O
</s>
<s>
OLTP	B-General_Concept
systems	O
emphasize	O
very	O
fast	O
query	O
processing	O
and	O
maintaining	O
data	O
integrity	O
in	O
multi-access	O
environments	O
.	O
</s>
<s>
For	O
OLTP	B-General_Concept
systems	O
,	O
effectiveness	O
is	O
measured	O
by	O
the	O
number	O
of	O
transactions	O
per	O
second	O
.	O
</s>
<s>
OLTP	B-General_Concept
databases	O
contain	O
detailed	O
and	O
current	O
data	O
.	O
</s>
<s>
Normalization	B-Application
is	O
the	O
norm	O
for	O
data	O
modeling	O
techniques	O
in	O
this	O
system	O
.	O
</s>
<s>
Predictive	B-General_Concept
analytics	I-General_Concept
is	O
about	O
finding	O
and	O
quantifying	O
hidden	O
patterns	O
in	O
the	O
data	O
using	O
complex	O
mathematical	O
models	O
that	O
can	O
be	O
used	O
to	O
predict	O
future	O
outcomes	O
.	O
</s>
<s>
Predictive	B-General_Concept
analysis	I-General_Concept
is	O
different	O
from	O
OLAP	B-Application
in	O
that	O
OLAP	B-Application
focuses	O
on	O
historical	O
data	B-General_Concept
analysis	I-General_Concept
and	O
is	O
reactive	O
in	O
nature	O
,	O
while	O
predictive	B-General_Concept
analysis	I-General_Concept
focuses	O
on	O
the	O
future	O
.	O
</s>
<s>
In	O
essence	O
,	O
the	O
data	O
warehousing	O
concept	O
was	O
intended	O
to	O
provide	O
an	O
architectural	O
model	O
for	O
the	O
flow	O
of	O
data	O
from	O
operational	O
systems	O
to	O
decision	B-Application
support	I-Application
environments	I-Application
.	O
</s>
<s>
In	O
the	O
absence	O
of	O
a	O
data	O
warehousing	O
architecture	O
,	O
an	O
enormous	O
amount	O
of	O
redundancy	B-Application
was	O
required	O
to	O
support	O
multiple	O
decision	B-Application
support	I-Application
environments	I-Application
.	O
</s>
<s>
In	O
larger	O
corporations	O
,	O
it	O
was	O
typical	O
for	O
multiple	O
decision	B-Application
support	I-Application
environments	I-Application
to	O
operate	O
independently	O
.	O
</s>
<s>
The	O
process	O
of	O
gathering	O
,	O
cleaning	O
and	O
integrating	O
data	O
from	O
various	O
sources	O
,	O
usually	O
from	O
long-term	O
existing	O
operational	O
systems	O
(	O
usually	O
referred	O
to	O
as	O
legacy	B-Device
systems	I-Device
)	O
,	O
was	O
typically	O
in	O
part	O
replicated	O
for	O
each	O
environment	O
.	O
</s>
<s>
Moreover	O
,	O
the	O
operational	O
systems	O
were	O
frequently	O
reexamined	O
as	O
new	O
decision	B-Application
support	I-Application
requirements	O
emerged	O
.	O
</s>
<s>
Often	O
new	O
requirements	O
necessitated	O
gathering	O
,	O
cleaning	O
and	O
integrating	O
new	O
data	O
from	O
"	O
data	B-General_Concept
marts	I-General_Concept
"	O
that	O
was	O
tailored	O
for	O
ready	O
access	O
by	O
users	O
.	O
</s>
<s>
1970s	O
–	O
ACNielsen	O
and	O
IRI	O
provide	O
dimensional	O
data	B-General_Concept
marts	I-General_Concept
for	O
retail	O
sales	O
.	O
</s>
<s>
1975	O
–	O
Sperry	O
Univac	O
introduces	O
MAPPER	B-Language
(	O
MAintain	O
,	O
Prepare	O
,	O
and	O
Produce	O
Executive	O
Reports	O
)	O
,	O
a	O
database	O
management	O
and	O
reporting	O
system	O
that	O
includes	O
the	O
world	O
's	O
first	O
4GL	B-Language
.	O
</s>
<s>
1983	O
–	O
Teradata	O
introduces	O
the	O
DBC/1012	B-Device
database	O
computer	O
specifically	O
designed	O
for	O
decision	B-Application
support	I-Application
.	O
</s>
<s>
2000	O
–	O
Dan	O
Linstedt	O
releases	O
in	O
the	O
public	O
domain	O
the	O
Data	O
vault	O
modeling	O
,	O
conceived	O
in	O
1990	O
as	O
an	O
alternative	O
to	O
Inmon	O
and	O
Kimball	O
to	O
provide	O
long-term	O
historical	O
storage	O
of	O
data	O
coming	O
in	O
from	O
multiple	O
operational	O
systems	O
,	O
with	O
emphasis	O
on	O
tracing	O
,	O
auditing	O
and	O
resilience	O
to	O
change	O
of	O
the	O
source	O
data	B-Application
model	I-Application
.	O
</s>
<s>
Once	O
raw	O
text	O
is	O
passed	O
through	O
textual	O
disambiguation	O
,	O
it	O
can	O
easily	O
and	O
efficiently	O
be	O
accessed	O
and	O
analyzed	O
by	O
standard	O
business	B-General_Concept
intelligence	I-General_Concept
technology	I-General_Concept
.	O
</s>
<s>
Facts	O
,	O
as	O
reported	O
by	O
the	O
reporting	O
entity	O
,	O
are	O
said	O
to	O
be	O
at	O
raw	O
level	O
;	O
e.g.	O
,	O
in	O
a	O
mobile	O
telephone	O
system	O
,	O
if	O
a	O
BTS	O
(	O
base	B-General_Concept
transceiver	I-General_Concept
station	I-General_Concept
)	O
receives	O
1,000	O
requests	O
for	O
traffic	O
channel	O
allocation	O
,	O
allocates	O
for	O
820	O
,	O
and	O
rejects	O
the	O
remaining	O
,	O
it	O
would	O
report	O
three	O
facts	O
or	O
measurements	O
to	O
a	O
management	O
system	O
:	O
</s>
<s>
There	O
are	O
three	O
or	O
more	O
leading	O
approaches	O
to	O
storing	O
data	O
in	O
a	O
data	O
warehouse	O
–	O
the	O
most	O
important	O
approaches	O
are	O
the	O
dimensional	B-Application
approach	I-Application
and	O
the	O
normalized	O
approach	O
.	O
</s>
<s>
The	O
dimensional	B-Application
approach	I-Application
refers	O
to	O
Ralph	O
Kimball	O
's	O
approach	O
in	O
which	O
it	O
is	O
stated	O
that	O
the	O
data	O
warehouse	O
should	O
be	O
modeled	O
using	O
a	O
Dimensional	O
Model/star	O
schema	O
.	O
</s>
<s>
The	O
normalized	O
approach	O
,	O
also	O
called	O
the	O
3NF	O
model	O
(	O
Third	O
Normal	B-Application
Form	I-Application
)	O
,	O
refers	O
to	O
Bill	O
Inmon	O
's	O
approach	O
in	O
which	O
it	O
is	O
stated	O
that	O
the	O
data	O
warehouse	O
should	O
be	O
modeled	O
using	O
an	O
E-R	O
model/normalized	O
model	O
.	O
</s>
<s>
In	O
a	O
dimensional	B-Application
approach	I-Application
,	O
transaction	B-General_Concept
data	I-General_Concept
is	O
partitioned	O
into	O
"	O
facts	O
"	O
,	O
which	O
are	O
generally	O
numeric	O
transaction	B-General_Concept
data	I-General_Concept
,	O
and	O
"	O
dimensions	O
"	O
,	O
which	O
are	O
the	O
reference	O
information	O
that	O
gives	O
context	O
to	O
the	O
facts	O
.	O
</s>
<s>
A	O
key	O
advantage	O
of	O
a	O
dimensional	B-Application
approach	I-Application
is	O
that	O
the	O
data	O
warehouse	O
is	O
easier	O
for	O
the	O
user	O
to	O
understand	O
and	O
to	O
use	O
.	O
</s>
<s>
Another	O
advantage	O
offered	O
by	O
dimensional	O
model	O
is	O
that	O
it	O
does	O
not	O
involve	O
a	O
relational	B-Application
database	I-Application
every	O
time	O
.	O
</s>
<s>
The	O
model	O
of	O
facts	O
and	O
dimensions	O
can	O
also	O
be	O
understood	O
as	O
a	O
data	B-Algorithm
cube	I-Algorithm
.	O
</s>
<s>
The	O
main	O
disadvantages	O
of	O
the	O
dimensional	B-Application
approach	I-Application
are	O
the	O
following	O
:	O
</s>
<s>
It	O
is	O
difficult	O
to	O
modify	O
the	O
data	O
warehouse	O
structure	O
if	O
the	O
organization	O
adopting	O
the	O
dimensional	B-Application
approach	I-Application
changes	O
the	O
way	O
in	O
which	O
it	O
does	O
business	O
.	O
</s>
<s>
In	O
the	O
normalized	O
approach	O
,	O
the	O
data	O
in	O
the	O
data	O
warehouse	O
are	O
stored	O
following	O
,	O
to	O
a	O
degree	O
,	O
database	B-Application
normalization	I-Application
rules	O
.	O
</s>
<s>
The	O
normalized	O
structure	O
divides	O
data	O
into	O
entities	O
,	O
which	O
creates	O
several	O
tables	O
in	O
a	O
relational	B-Application
database	I-Application
.	O
</s>
<s>
Some	O
disadvantages	O
of	O
this	O
approach	O
are	O
that	O
,	O
because	O
of	O
the	O
number	O
of	O
tables	O
involved	O
,	O
it	O
can	O
be	O
difficult	O
for	O
users	O
to	O
join	O
data	O
from	O
different	O
sources	O
into	O
meaningful	O
information	O
and	O
to	O
access	O
the	O
information	O
without	O
a	O
precise	O
understanding	O
of	O
the	O
sources	O
of	O
data	O
and	O
of	O
the	O
data	B-General_Concept
structure	I-General_Concept
of	O
the	O
data	O
warehouse	O
.	O
</s>
<s>
Both	O
normalized	O
and	O
dimensional	O
models	O
can	O
be	O
represented	O
in	O
entity	B-Architecture
–	I-Architecture
relationship	I-Architecture
diagrams	I-Architecture
as	O
both	O
contain	O
joined	O
relational	O
tables	O
.	O
</s>
<s>
The	O
difference	O
between	O
the	O
two	O
models	O
is	O
the	O
degree	O
of	O
normalization	B-Application
(	O
also	O
known	O
as	O
Normal	B-Application
Forms	I-Application
)	O
.	O
</s>
<s>
In	O
the	O
bottom-up	O
approach	O
,	O
data	B-General_Concept
marts	I-General_Concept
are	O
first	O
created	O
to	O
provide	O
reporting	O
and	O
analytical	O
capabilities	O
for	O
specific	O
business	O
processes	O
.	O
</s>
<s>
These	O
data	B-General_Concept
marts	I-General_Concept
can	O
then	O
be	O
integrated	O
to	O
create	O
a	O
comprehensive	O
data	O
warehouse	O
.	O
</s>
<s>
The	O
data	O
warehouse	O
bus	O
architecture	O
is	O
primarily	O
an	O
implementation	O
of	O
"	O
the	O
bus	O
"	O
,	O
a	O
collection	O
of	O
conformed	O
dimensions	O
and	O
conformed	O
facts	O
,	O
which	O
are	O
dimensions	O
that	O
are	O
shared	O
(	O
in	O
a	O
specific	O
way	O
)	O
between	O
facts	O
in	O
two	O
or	O
more	O
data	B-General_Concept
marts	I-General_Concept
.	O
</s>
<s>
The	O
top-down	O
approach	O
is	O
designed	O
using	O
a	O
normalized	O
enterprise	O
data	B-Application
model	I-Application
.	O
</s>
<s>
Dimensional	O
data	B-General_Concept
marts	I-General_Concept
containing	O
data	O
needed	O
for	O
specific	O
business	O
processes	O
or	O
specific	O
departments	O
are	O
created	O
from	O
the	O
data	O
warehouse	O
.	O
</s>
<s>
Data	O
warehouses	O
often	O
resemble	O
the	O
hub	B-Architecture
and	I-Architecture
spokes	I-Architecture
architecture	I-Architecture
.	O
</s>
<s>
Legacy	B-Device
systems	I-Device
feeding	O
the	O
warehouse	O
often	O
include	O
customer	O
relationship	O
management	O
and	O
enterprise	O
resource	O
planning	O
,	O
generating	O
large	O
amounts	O
of	O
data	O
.	O
</s>
<s>
To	O
consolidate	O
these	O
various	O
data	B-Application
models	I-Application
,	O
and	O
facilitate	O
the	O
extract	O
transform	O
load	O
process	O
,	O
data	O
warehouses	O
often	O
make	O
use	O
of	O
an	O
operational	O
data	O
store	O
,	O
the	O
information	O
from	O
which	O
is	O
parsed	O
into	O
the	O
actual	O
data	O
warehouse	O
.	O
</s>
<s>
To	O
reduce	O
data	B-Application
redundancy	I-Application
,	O
larger	O
systems	O
often	O
store	O
the	O
data	O
in	O
a	O
normalized	O
way	O
.	O
</s>
<s>
Data	B-General_Concept
marts	I-General_Concept
for	O
specific	O
reports	O
can	O
then	O
be	O
built	O
on	O
top	O
of	O
the	O
data	O
warehouse	O
.	O
</s>
<s>
A	O
hybrid	O
(	O
also	O
called	O
ensemble	O
)	O
data	O
warehouse	O
database	O
is	O
kept	O
on	O
third	O
normal	B-Application
form	I-Application
to	O
eliminate	O
data	B-Application
redundancy	I-Application
.	O
</s>
<s>
A	O
normal	O
relational	B-Application
database	I-Application
,	O
however	O
,	O
is	O
not	O
efficient	O
for	O
business	B-General_Concept
intelligence	I-General_Concept
reports	O
where	O
dimensional	O
modelling	O
is	O
prevalent	O
.	O
</s>
<s>
Small	O
data	B-General_Concept
marts	I-General_Concept
can	O
shop	O
for	O
data	O
from	O
the	O
consolidated	O
warehouse	O
and	O
use	O
the	O
filtered	O
,	O
specific	O
data	O
for	O
the	O
fact	O
tables	O
and	O
dimensions	O
required	O
.	O
</s>
<s>
The	O
data	O
warehouse	O
provides	O
a	O
single	O
source	O
of	O
information	O
from	O
which	O
the	O
data	B-General_Concept
marts	I-General_Concept
can	O
read	O
,	O
providing	O
a	O
wide	O
range	O
of	O
business	B-General_Concept
information	I-General_Concept
.	O
</s>
<s>
The	O
hybrid	O
architecture	O
allows	O
a	O
data	O
warehouse	O
to	O
be	O
replaced	O
with	O
a	O
master	B-General_Concept
data	I-General_Concept
management	I-General_Concept
repository	B-General_Concept
where	O
operational	O
(	O
not	O
static	O
)	O
information	O
could	O
reside	O
.	O
</s>
<s>
The	O
data	O
vault	O
modeling	O
components	O
follow	O
hub	B-Architecture
and	I-Architecture
spokes	I-Architecture
architecture	I-Architecture
.	O
</s>
<s>
This	O
modeling	O
style	O
is	O
a	O
hybrid	O
design	O
,	O
consisting	O
of	O
the	O
best	O
practices	O
from	O
both	O
third	O
normal	B-Application
form	I-Application
and	O
star	B-Application
schema	I-Application
.	O
</s>
<s>
The	O
data	O
vault	O
model	O
is	O
not	O
a	O
true	O
third	O
normal	B-Application
form	I-Application
,	O
and	O
breaks	O
some	O
of	O
its	O
rules	O
,	O
but	O
it	O
is	O
a	O
top-down	O
architecture	O
with	O
a	O
bottom	O
up	O
design	O
.	O
</s>
<s>
It	O
is	O
not	O
geared	O
to	O
be	O
end-user	O
accessible	O
,	O
which	O
,	O
when	O
built	O
,	O
still	O
requires	O
the	O
use	O
of	O
a	O
data	B-General_Concept
mart	I-General_Concept
or	O
star	O
schema-based	O
release	O
area	O
for	O
business	O
purposes	O
.	O
</s>
<s>
There	O
are	O
basic	O
features	O
that	O
define	O
the	O
data	O
in	O
the	O
data	O
warehouse	O
that	O
include	O
subject	O
orientation	O
,	O
data	B-General_Concept
integration	I-General_Concept
,	O
time-variant	O
,	O
nonvolatile	O
data	O
,	O
and	O
data	O
granularity	O
.	O
</s>
<s>
Subject	O
orientation	O
is	O
not	O
database	B-Application
normalization	I-Application
.	O
</s>
<s>
It	O
is	O
mainly	O
meant	O
for	O
data	B-Application
mining	I-Application
and	O
forecasting	O
.	O
</s>
<s>
In	O
the	O
data	O
warehouse	O
process	O
,	O
data	O
can	O
be	O
aggregated	O
in	O
data	B-General_Concept
marts	I-General_Concept
at	O
different	O
levels	O
of	O
abstraction	O
.	O
</s>
<s>
With	O
data	B-General_Concept
virtualization	I-General_Concept
,	O
the	O
data	O
used	O
remains	O
in	O
its	O
original	O
locations	O
and	O
real-time	O
access	O
is	O
established	O
to	O
allow	O
analytics	O
across	O
multiple	O
sources	O
creating	O
a	O
virtual	O
data	O
warehouse	O
.	O
</s>
<s>
However	O
,	O
with	O
data	B-General_Concept
virtualization	I-General_Concept
,	O
the	O
connection	O
to	O
all	O
necessary	O
data	O
sources	O
must	O
be	O
operational	O
as	O
there	O
is	O
no	O
local	O
copy	O
of	O
the	O
data	O
,	O
which	O
is	O
one	O
of	O
the	O
main	O
drawbacks	O
of	O
the	O
approach	O
.	O
</s>
<s>
Operational	O
systems	O
are	O
optimized	O
for	O
the	O
preservation	O
of	O
data	O
integrity	O
and	O
speed	O
of	O
recording	O
of	O
business	O
transactions	O
through	O
use	O
of	O
database	B-Application
normalization	I-Application
and	O
an	O
entity	B-Architecture
–	I-Architecture
relationship	I-Architecture
model	I-Architecture
.	O
</s>
<s>
Operational	O
system	O
designers	O
generally	O
follow	O
Codd	B-Application
's	I-Application
12	I-Application
rules	I-Application
of	O
database	B-Application
normalization	I-Application
to	O
ensure	O
data	O
integrity	O
.	O
</s>
<s>
Fully	O
normalized	O
database	O
designs	O
(	O
that	O
is	O
,	O
those	O
satisfying	O
all	O
Codd	B-Application
rules	I-Application
)	O
often	O
result	O
in	O
information	O
from	O
a	O
business	O
transaction	O
being	O
stored	O
in	O
dozens	O
to	O
hundreds	O
of	O
tables	O
.	O
</s>
<s>
Relational	B-Application
databases	I-Application
are	O
efficient	O
at	O
managing	O
the	O
relationships	O
between	O
these	O
tables	O
.	O
</s>
<s>
Because	O
of	O
these	O
differences	O
in	O
access	O
patterns	O
,	O
operational	O
databases	O
(	O
loosely	O
,	O
OLTP	B-General_Concept
)	O
benefit	O
from	O
the	O
use	O
of	O
a	O
row-oriented	B-General_Concept
DBMS	I-General_Concept
whereas	O
analytics	O
databases	O
(	O
loosely	O
,	O
OLAP	B-Application
)	O
benefit	O
from	O
the	O
use	O
of	O
a	O
column-oriented	B-General_Concept
DBMS	I-General_Concept
.	O
</s>
<s>
Offline	O
data	O
warehouse	O
Data	O
warehouses	O
at	O
this	O
stage	O
are	O
updated	O
from	O
data	O
in	O
the	O
operational	O
systems	O
on	O
a	O
regular	O
basis	O
and	O
the	O
data	O
warehouse	O
data	O
are	O
stored	O
in	O
a	O
data	B-General_Concept
structure	I-General_Concept
designed	O
to	O
facilitate	O
reporting	O
.	O
</s>
