<s>
SQL/PSM	B-Language
(	O
SQL/Persistent	O
Stored	O
Modules	O
)	O
is	O
an	O
ISO	O
standard	O
mainly	O
defining	O
an	O
extension	O
of	O
SQL	B-Language
with	O
a	O
procedural	B-Application
language	I-Application
for	O
use	O
in	O
stored	B-General_Concept
procedures	I-General_Concept
.	O
</s>
<s>
Initially	O
published	O
in	O
1996	O
as	O
an	O
extension	O
of	O
SQL-92	B-Language
(	O
ISO/IEC	O
9075-4:1996	O
,	O
a	O
version	O
sometimes	O
called	O
PSM-96	O
or	O
even	O
SQL-92/PSM	O
)	O
,	O
SQL/PSM	B-Language
was	O
later	O
incorporated	O
into	O
the	O
multi-part	O
SQL:1999	B-Language
standard	O
,	O
and	O
has	O
been	O
part	O
4	O
of	O
that	O
standard	O
since	O
then	O
,	O
most	O
recently	O
in	O
SQL:2016	B-Language
.	O
</s>
<s>
The	O
SQL:1999	B-Language
part	O
4	O
covered	O
less	O
than	O
the	O
original	O
PSM-96	O
because	O
the	O
SQL	B-Language
statements	O
for	O
defining	O
,	O
managing	O
,	O
and	O
invoking	O
routines	O
were	O
actually	O
incorporated	O
into	O
part	O
2	O
SQL/Foundation	O
,	O
leaving	O
only	O
the	O
procedural	B-Application
language	I-Application
itself	O
as	O
SQL/PSM	B-Language
.	O
</s>
<s>
The	O
SQL/PSM	B-Language
facilities	O
are	O
still	O
optional	O
as	O
far	O
as	O
the	O
SQL	B-Language
standard	O
is	O
concerned	O
;	O
most	O
of	O
them	O
are	O
grouped	O
in	O
Features	O
P001-P008	O
.	O
</s>
<s>
SQL/PSM	B-Language
standardizes	O
syntax	O
and	O
semantics	O
for	O
control	O
flow	O
,	O
exception	B-General_Concept
handling	I-General_Concept
(	O
called	O
"	O
condition	O
handling	O
"	O
in	O
SQL/PSM	B-Language
)	O
,	O
local	O
variables	O
,	O
assignment	O
of	O
expressions	O
to	O
variables	O
and	O
parameters	O
,	O
and	O
(	O
procedural	B-Application
)	O
use	O
of	O
cursors	B-Language
.	O
</s>
<s>
It	O
also	O
defines	O
an	O
information	O
schema	O
(	O
metadata	O
)	O
for	O
stored	B-General_Concept
procedures	I-General_Concept
.	O
</s>
<s>
SQL/PSM	B-Language
is	O
one	O
language	O
in	O
which	O
methods	B-Language
for	O
the	O
SQL:1999	B-Language
structured	B-Language
types	I-Language
can	O
be	O
defined	O
.	O
</s>
<s>
The	O
other	O
is	O
Java	O
,	O
via	O
SQL/JRT	B-Language
.	O
</s>
<s>
SQL/PSM	B-Language
is	O
derived	O
,	O
seemingly	O
directly	O
,	O
from	O
Oracle	B-General_Concept
's	O
PL/SQL	B-Language
.	O
</s>
<s>
Oracle	B-General_Concept
developed	O
PL/SQL	B-Language
and	O
released	O
it	O
in	O
1991	O
,	O
basing	O
the	O
language	O
on	O
the	O
US	O
Department	O
of	O
Defense	O
's	O
Ada	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
However	O
,	O
Oracle	B-General_Concept
has	O
maintained	O
a	O
distance	O
from	O
the	O
standard	O
in	O
its	O
documentation	O
.	O
</s>
<s>
IBM	O
's	O
SQL	B-Application
PL	I-Application
(	O
used	O
in	O
DB2	O
)	O
and	O
Mimer	B-Application
SQL	I-Application
's	O
PSM	O
were	O
the	O
first	O
two	O
products	O
officially	O
implementing	O
SQL/PSM	B-Language
.	O
</s>
<s>
It	O
is	O
commonly	O
thought	O
that	O
these	O
two	O
languages	O
,	O
and	O
perhaps	O
also	O
MySQL/MariaDB	O
'	O
s	O
procedural	B-Application
language	I-Application
,	O
are	O
closest	O
to	O
the	O
SQL/PSM	B-Language
standard	O
.	O
</s>
<s>
However	O
,	O
a	O
PostgreSQL	B-Application
addon	O
implements	O
SQL/PSM	B-Language
(	O
alongside	O
its	O
other	O
procedural	B-Application
languages	I-Application
like	O
the	O
PL/SQL	B-Language
-derived	O
plpgsql	B-Language
)	O
,	O
although	O
it	O
is	O
not	O
part	O
of	O
the	O
core	O
product	O
.	O
</s>
<s>
RDF	O
functionality	O
in	O
OpenLink	B-Application
Virtuoso	I-Application
was	O
developed	O
entirely	O
through	O
SQL/PSM	B-Language
,	O
combined	O
with	O
custom	O
datatypes	O
(	O
e.g.	O
,	O
ANY	O
for	O
handling	O
URI	O
and	O
Literal	O
relation	O
objects	O
)	O
,	O
sophisticated	O
indexing	O
,	O
and	O
flexible	O
physical	O
storage	O
choices	O
(	O
column-wise	O
or	O
row-wise	O
)	O
.	O
</s>
