<s>
In	O
information	O
science	O
and	O
information	B-General_Concept
technology	I-General_Concept
,	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
(	O
SSOT	O
)	O
architecture	O
,	O
or	O
single	B-Application
point	I-Application
of	I-Application
truth	I-Application
(	O
SPOT	O
)	O
architecture	O
,	O
for	O
information	O
systems	O
is	O
the	O
practice	O
of	O
structuring	O
information	B-Application
models	I-Application
and	O
associated	O
data	O
schemas	B-Application
such	O
that	O
every	O
data	O
element	O
is	O
mastered	O
(	O
or	O
edited	O
)	O
in	O
only	O
one	O
place	O
,	O
providing	O
data	O
normalization	B-Application
to	O
a	O
canonical	O
form	O
(	O
for	O
example	O
,	O
in	O
database	B-Application
normalization	I-Application
or	O
content	O
transclusion	O
)	O
.	O
</s>
<s>
Any	O
possible	O
linkages	O
to	O
this	O
data	O
element	O
(	O
possibly	O
in	O
other	O
areas	O
of	O
the	O
relational	O
schema	B-Application
or	O
even	O
in	O
distant	O
federated	B-General_Concept
databases	I-General_Concept
)	O
are	O
by	O
reference	O
only	O
.	O
</s>
<s>
Because	O
all	O
other	O
locations	O
of	O
the	O
data	O
just	O
refer	O
back	O
to	O
the	O
primary	O
"	O
source	O
of	O
truth	O
"	O
location	O
,	O
updates	O
to	O
the	O
data	O
element	O
in	O
the	O
primary	O
location	O
propagate	O
to	O
the	O
entire	O
system	O
,	O
providing	O
multiple	O
advantages	O
simultaneously	O
:	O
greater	O
efficiency/productivity	O
,	O
easy	O
prevention	O
of	O
mistaken	O
inconsistencies	O
(	O
such	O
as	O
a	O
duplicate	O
value/copy	O
somewhere	O
being	O
forgotten	O
)	O
,	O
and	O
greatly	O
simplified	O
version	B-Architecture
control	I-Architecture
.	O
</s>
<s>
In	O
electronic	B-Application
health	I-Application
records	I-Application
(	O
EHRs	B-Application
)	O
,	O
it	O
is	O
imperative	O
to	O
accurately	O
validate	O
patient	O
identity	O
against	O
a	O
single	O
referential	O
repository	O
,	O
which	O
serves	O
as	O
the	O
SSOT	O
.	O
</s>
<s>
This	O
ensures	O
that	O
data	O
updates	O
to	O
elements	O
in	O
the	O
authoritative	O
location	O
are	O
comprehensively	O
distributed	O
to	O
all	O
federated	B-General_Concept
database	I-General_Concept
constituencies	O
in	O
the	O
larger	O
overall	O
enterprise	O
architecture	O
.	O
</s>
<s>
EHRs	B-Application
are	O
an	O
excellent	O
class	O
for	O
exemplifying	O
how	O
SSOT	O
architecture	O
is	O
both	O
poignantly	O
necessary	O
and	O
challenging	O
to	O
achieve	O
:	O
it	O
is	O
challenging	O
because	O
inter-organization	O
health	O
information	O
exchange	O
is	O
inherently	O
a	O
cybersecurity	O
competence	O
hurdle	O
,	O
and	O
nonetheless	O
it	O
is	O
necessary	O
,	O
to	O
prevent	O
medical	O
errors	O
,	O
to	O
prevent	O
the	O
wasted	O
costs	O
of	O
inefficiency	O
(	O
such	O
as	O
duplicated	O
work	O
or	O
rework	O
)	O
,	O
and	O
to	O
make	O
the	O
primary	O
care	O
and	O
medical	O
home	O
concepts	O
feasible	O
(	O
to	O
achieve	O
competent	O
care	O
transitions	O
)	O
.	O
</s>
<s>
Single-source	B-Application
publishing	I-Application
as	O
a	O
general	O
principle	O
or	O
ideal	O
in	O
content	B-Protocol
management	I-Protocol
relies	O
on	O
having	O
SSOTs	O
,	O
via	O
transclusion	O
or	O
(	O
otherwise	O
,	O
at	O
least	O
)	O
substitution	O
.	O
</s>
<s>
Substitution	O
happens	O
via	O
libraries	O
of	O
objects	O
that	O
can	O
be	O
propagated	O
as	O
static	O
copies	O
which	O
are	O
later	O
refreshed	O
when	O
necessary	O
(	O
that	O
is	O
,	O
when	O
refreshing	O
of	O
the	O
copy-paste	B-General_Concept
or	O
import	B-General_Concept
is	O
triggered	O
by	O
a	O
larger	O
updating	O
event	O
,	O
such	O
as	O
a	O
new	O
scientific	O
advance	O
or	O
a	O
piece	O
of	O
breaking	O
news	O
)	O
.	O
</s>
<s>
Component	B-Language
content	I-Language
management	I-Language
systems	I-Language
are	O
a	O
class	O
of	O
content	B-Protocol
management	I-Protocol
systems	I-Protocol
that	O
aim	O
to	O
provide	O
competence	O
on	O
this	O
level	O
.	O
</s>
<s>
An	O
acknowledged	O
prerequisite	O
(	O
of	O
the	O
notion	O
that	O
any	O
given	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
can	O
exist	O
)	O
is	O
that	O
it	O
depends	O
on	O
the	O
ontologic	O
condition	O
that	O
no	O
more	O
than	O
a	O
single	O
truth	O
(	O
about	O
any	O
particular	O
fact	O
or	O
idea	O
)	O
exists	O
,	O
an	O
assertion	O
that	O
is	O
ontologic	O
in	O
both	O
the	O
IT	O
sense	O
and	O
the	B-Language
general	I-Language
sense	I-Language
of	O
that	O
word	O
.	O
</s>
<s>
The	O
broadest	O
contexts	O
(	O
and	O
thus	O
thorniest	O
,	O
regarding	O
ontologic	O
discrepancies	O
)	O
require	O
adequate	O
epistemic	O
regime	O
comparison	O
and	O
reconciliation	B-General_Concept
(	O
or	O
at	O
least	O
negotiation	O
or	O
transactional	O
exchanges	O
)	O
.	O
</s>
<s>
An	O
archetypal	O
example	O
of	O
this	O
class	O
of	O
reconciliation	B-General_Concept
is	O
that	O
two	O
theological	O
seminary	O
libraries	O
,	O
from	O
two	O
different	O
religions	O
(	O
X	O
and	O
Y	O
)	O
,	O
could	O
exchange	O
information	O
with	O
an	O
SSOT	O
architecture	O
,	O
but	O
the	O
unification	O
of	O
truth	O
would	O
reside	O
on	O
the	O
level	O
of	O
the	O
statement	O
that	O
"	O
religion	O
X	O
asserts	O
that	O
God	O
is	O
purple	O
whereas	O
religion	O
Y	O
asserts	O
that	O
God	O
is	O
green	O
"	O
,	O
rather	O
than	O
on	O
the	O
level	O
of	O
"	O
God	O
is	O
purple	O
"	O
or	O
"	O
God	O
is	O
green	O
"	O
.	O
</s>
<s>
This	O
platform-agnostic	B-Operating_System
concept	O
has	O
civil	O
applications	O
and	O
foreign	O
relations	O
applications	O
as	O
well	O
,	O
regarding	O
jurisdictional	O
differences	O
in	O
legal	O
definitions	O
:	O
for	O
example	O
,	O
whether	O
any	O
particular	O
economic	O
lens	O
is	O
good	O
,	O
bad	O
,	O
or	O
syncretizible	O
(	O
e.g.	O
,	O
capitalism	O
,	O
socialism	O
,	O
mixed	O
economy	O
)	O
,	O
legal	O
definitions	O
of	O
marriage	O
(	O
EHR	O
example	O
:	O
is	O
patient	O
X	O
married	O
or	O
not	O
,	O
according	O
to	O
which	O
state	O
law	O
or	O
its	O
interstate	O
reciprocity	O
)	O
,	O
whether	O
sex	O
assignment	O
equals	O
legal	O
gender	O
(	O
EHR	O
example	O
:	O
what	O
is	O
the	O
gender	O
or	O
gender	O
identity	O
of	O
patient	O
X	O
,	O
according	O
to	O
the	O
patient	O
themselves	O
(	O
self-report	O
)	O
or	O
according	O
to	O
someone	O
else	O
)	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
enterprise	O
resource	O
planning	O
(	O
ERP	O
)	O
system	O
(	O
such	O
as	O
SAP	B-Application
or	O
Oracle	B-Application
e-Business	I-Application
Suite	I-Application
)	O
may	O
store	O
a	O
customer	O
record	O
;	O
the	O
customer	O
relationship	O
management	O
(	O
CRM	O
)	O
system	O
also	O
needs	O
a	O
copy	O
of	O
the	O
customer	O
record	O
(	O
or	O
part	O
of	O
it	O
)	O
and	O
the	O
warehouse	O
dispatch	O
system	O
might	O
also	O
need	O
a	O
copy	O
of	O
some	O
or	O
all	O
of	O
the	O
customer	O
data	O
(	O
e.g.	O
,	O
shipping	O
address	O
)	O
.	O
</s>
<s>
For	O
organisations	O
(	O
with	O
more	O
than	O
one	O
information	O
system	O
)	O
wishing	O
to	O
implement	O
a	O
Single	B-Application
Source	I-Application
of	I-Application
Truth	I-Application
(	O
without	O
modifying	O
all	O
but	O
one	O
master	O
system	O
to	O
store	O
pointers	O
to	O
other	O
systems	O
for	O
all	O
entities	O
)	O
,	O
four	O
supporting	O
architectures	O
are	O
commonly	O
used	O
:	O
</s>
<s>
An	O
enterprise	B-Application
service	I-Application
bus	I-Application
(	O
ESB	O
)	O
allows	O
any	O
number	O
of	O
systems	O
in	O
an	O
organisation	O
to	O
receive	O
updates	O
of	O
data	O
that	O
has	O
changed	O
in	O
another	O
system	O
.	O
</s>
<s>
To	O
implement	O
a	O
Single	B-Application
Source	I-Application
of	I-Application
Truth	I-Application
,	O
a	O
single	B-Application
source	I-Application
system	O
of	O
correct	O
data	O
for	O
any	O
entity	O
must	O
be	O
identified	O
.	O
</s>
<s>
Changes	O
to	O
this	O
entity	O
(	O
creates	B-General_Concept
,	I-General_Concept
updates	I-General_Concept
,	I-General_Concept
and	I-General_Concept
deletes	I-General_Concept
)	O
are	O
then	O
published	O
via	O
the	O
ESB	O
;	O
other	O
systems	O
which	O
need	O
to	O
retain	O
a	O
copy	O
of	O
that	O
data	O
subscribe	O
to	O
this	O
update	O
,	O
and	O
update	O
their	O
own	O
records	O
accordingly	O
.	O
</s>
<s>
Generally	O
,	O
however	O
,	O
the	O
data	O
available	O
from	O
the	O
data	O
warehouse	O
are	O
not	O
used	O
to	O
update	O
other	O
systems	O
;	O
rather	O
the	O
DW	O
becomes	O
the	O
"	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
"	O
for	O
reporting	O
to	O
multiple	O
stakeholders	O
.	O
</s>
<s>
In	O
this	O
context	O
,	O
the	O
Data	O
Warehouse	O
is	O
more	O
correctly	O
referred	O
to	O
as	O
a	O
"	O
single	B-Application
version	I-Application
of	I-Application
the	I-Application
truth	I-Application
"	O
since	O
other	O
versions	O
of	O
the	O
truth	O
exist	O
in	O
its	O
operational	O
data	O
sources	O
(	O
no	O
data	O
originates	O
in	O
the	O
DW	O
;	O
it	O
is	O
simply	O
a	O
reporting	O
mechanism	O
for	O
data	O
loaded	O
from	O
operational	O
systems	O
)	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
you	O
need	O
an	O
Event	B-General_Concept
Store	I-General_Concept
,	O
a	O
particular	O
type	O
of	O
database	O
designed	O
to	O
hold	O
all	O
the	O
events	O
that	O
change	O
the	O
state	O
of	O
the	O
system	O
.	O
</s>
<s>
The	O
event	B-General_Concept
store	I-General_Concept
in	O
an	O
+	O
Command	O
Query	O
Responsibility	O
Separation	O
+	O
Domain	O
Driven	O
Design	O
+	O
Messaging	B-Operating_System
architecture	O
is	O
in	O
fact	O
a	O
"	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
"	O
,	O
with	O
the	O
additional	O
advantage	O
that	O
it	O
can	O
also	O
act	O
as	O
an	O
Enterprise	B-Application
Service	I-Application
Bus	I-Application
as	O
it	O
can	O
be	O
put	O
into	O
I	O
listen	O
directly	O
to	O
the	O
event	B-General_Concept
store	I-General_Concept
for	O
status	O
changes	O
as	O
everyone	O
passes	O
by	O
.	O
</s>
<s>
As	O
a	O
last	O
advantage	O
,	O
it	O
has	O
that	O
through	O
this	O
system	O
the	O
can	O
be	O
implemented	O
,	O
another	O
technique	O
not	O
mentioned	O
to	O
obtain	O
a	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
.	O
</s>
<s>
In	O
software	O
design	O
,	O
the	O
same	O
schema	B-Application
,	O
business	O
logic	O
and	O
other	O
components	O
are	O
often	O
repeated	O
in	O
multiple	O
different	O
contexts	O
,	O
while	O
each	O
version	O
refers	O
to	O
itself	O
as	O
"	O
Source	O
Code	O
"	O
.	O
</s>
<s>
To	O
address	O
this	O
problem	O
,	O
the	O
concepts	O
of	O
SSOT	O
can	O
also	O
be	O
applied	O
to	O
software	O
development	O
principles	O
using	O
processes	O
like	O
recursive	O
transcompiling	O
to	O
iteratively	O
turn	O
a	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
into	O
many	O
different	O
kinds	O
of	O
source	O
code	O
,	O
which	O
will	O
match	O
each	O
other	O
structurally	O
because	O
they	O
are	O
all	O
derived	O
from	O
the	O
same	O
SSOT	O
.	O
</s>
<s>
Adoption	O
of	O
a	O
single	B-Application
source	I-Application
of	I-Application
truth	I-Application
execution	O
model	O
is	O
on	O
the	O
rise	O
in	O
the	O
energy	O
sector	O
,	O
where	O
the	O
technological	O
advancements	O
brought	O
about	O
by	O
Industry	B-General_Concept
4.0	I-General_Concept
have	O
enabled	O
operators	O
to	O
improve	O
field	O
productivity	O
.	O
</s>
