<s>
QVT	B-Language
(	O
Query/View/Transformation	O
)	O
is	O
a	O
standard	O
set	O
of	O
languages	O
for	O
model	B-Language
transformation	I-Language
defined	O
by	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
.	O
</s>
<s>
Model	B-Language
transformation	I-Language
is	O
a	O
key	O
technique	O
used	O
in	O
model-driven	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
As	O
the	O
name	O
QVT	B-Language
indicates	O
,	O
the	O
OMG	O
standard	O
covers	O
transformations	O
,	O
views	O
and	O
queries	O
together	O
.	O
</s>
<s>
Model	O
queries	O
and	O
model	O
views	O
can	O
be	O
seen	O
as	O
special	O
kinds	O
of	O
model	B-Language
transformation	I-Language
,	O
provided	O
that	O
we	O
use	O
a	O
suitably	O
broad	O
definition	O
of	O
model	B-Language
transformation	I-Language
:	O
a	O
model	B-Language
transformation	I-Language
is	O
a	O
program	O
which	O
operates	O
on	O
models	O
.	O
</s>
<s>
The	O
QVT	B-Language
standard	O
defines	O
three	O
model	B-Language
transformation	I-Language
languages	I-Language
.	O
</s>
<s>
All	O
of	O
them	O
operate	O
on	O
models	O
which	O
conform	O
to	O
Meta-Object	B-Application
Facility	I-Application
(	O
MOF	B-Application
)	O
2.0	O
metamodels	O
;	O
the	O
transformation	O
states	O
which	O
metamodels	O
are	O
used	O
.	O
</s>
<s>
A	O
transformation	O
in	O
any	O
of	O
the	O
three	O
QVT	B-Language
languages	O
can	O
itself	O
be	O
regarded	O
as	O
a	O
model	O
,	O
conforming	O
to	O
one	O
of	O
the	O
metamodels	O
specified	O
in	O
the	O
standard	O
.	O
</s>
<s>
The	O
QVT	B-Language
standard	O
integrates	O
the	O
OCL	B-Language
2.0	O
standard	O
and	O
also	O
extends	O
it	O
with	O
imperative	O
features	O
.	O
</s>
<s>
QVT-Operational	O
is	O
an	O
imperative	O
language	O
designed	O
for	O
writing	O
unidirectional	O
transformations	O
.	O
</s>
<s>
QVT-Relations	O
is	O
a	O
declarative	O
language	O
designed	O
to	O
permit	O
both	O
unidirectional	O
and	O
bidirectional	O
model	B-Language
transformations	I-Language
to	O
be	O
written	O
.	O
</s>
<s>
The	O
QVT-Relations	O
language	O
has	O
both	O
a	O
textual	O
and	O
a	O
graphical	O
concrete	O
syntax	O
.	O
</s>
<s>
QVT-Core	O
is	O
a	O
declarative	O
language	O
designed	O
to	O
be	O
simple	O
and	O
to	O
act	O
as	O
the	O
target	O
of	O
translation	O
from	O
QVT-Relations	O
.	O
</s>
<s>
However	O
,	O
QVT-Core	O
has	O
never	O
had	O
a	O
full	O
implementation	O
and	O
in	O
fact	O
it	O
is	O
not	O
as	O
expressive	O
as	O
QVT-Relations	O
.	O
</s>
<s>
Hence	O
the	O
QVT	B-Language
Architecture	O
pictured	O
above	O
is	O
misleading	O
:	O
the	O
transformation	O
from	O
QVT-Relations	O
to	O
QVT-Core	O
given	O
in	O
the	O
QVT	B-Language
Standard	O
is	O
not	O
semantics-preserving	O
.	O
</s>
<s>
Finally	O
,	O
QVT-BlackBox	O
is	O
a	O
mechanism	O
to	O
invoke	O
transformation	O
facilities	O
expressed	O
in	O
other	O
languages	O
(	O
for	O
example	O
XSLT	B-Application
or	O
XQuery	B-Language
)	O
.	O
</s>
<s>
Although	O
QVT	B-Language
has	O
a	O
broad	O
scope	O
,	O
it	O
does	O
not	O
cover	O
everything	O
that	O
has	O
been	O
considered	O
as	O
a	O
model	B-Language
transformation	I-Language
,	O
view	O
or	O
query	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
QVT	B-Language
languages	O
do	O
not	O
permit	O
transformations	O
to	O
or	O
from	O
textual	O
models	O
,	O
since	O
each	O
model	O
must	O
conform	O
to	O
some	O
MOF	B-Application
2.0	O
metamodel	O
.	O
</s>
<s>
Model-to-text	O
transformations	O
are	O
being	O
standardised	O
separately	O
by	O
OMG	O
(	O
see	O
MOFM2T	B-Language
)	O
.	O
</s>
<s>
In	O
2002	O
,	O
OMG	O
issued	O
a	O
Request	O
for	O
proposal	O
(	O
RFP	O
)	O
on	O
MOF	B-Application
Query/View/Transformation	O
to	O
seek	O
a	O
standard	O
compatible	O
with	O
the	O
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
(	O
MDA	O
)	O
recommendation	O
suite	O
(	O
UML	O
,	O
MOF	B-Application
,	O
OCL	B-Language
,	O
etc	O
.	O
</s>
<s>
QVT	B-Language
Version	O
1.1	O
was	O
released	O
in	O
January	O
2011	O
.	O
</s>
<s>
QVT-Operational	O
:	O
</s>
<s>
Borland	B-Application
Together	I-Application
contains	O
an	O
implementation	O
of	O
QVT	B-Language
Operational	O
,	O
which	O
has	O
been	O
contributed	O
to	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
and	O
is	O
now	O
developed	O
as	O
the	O
Eclipse	B-Application
M2M	I-Application
Operational	O
QVT	B-Language
project	O
.	O
</s>
<s>
Eclipse	B-Application
M2M	I-Application
Operational	O
QVT	B-Language
:	O
official	O
Eclipse	O
open	O
source	O
implementation	O
of	O
QVT	B-Language
Operational	O
.	O
</s>
<s>
MagicDraw	B-Protocol
has	O
the	O
QVT	B-Language
plugin	O
which	O
uses	O
Operational	O
QVT	B-Language
implementation	O
that	O
is	O
provided	O
by	O
the	O
Eclipse	B-Application
M2M	I-Application
project	O
.	O
</s>
<s>
SmartQVT	B-Language
:	O
an	O
Eclipse	O
open	O
source	O
implementation	O
(	O
Orange	O
Labs	O
)	O
of	O
the	O
QVT-Operational	O
language	O
.	O
</s>
<s>
QVT-Core	O
:	O
</s>
<s>
OptimalJ	B-Language
:	O
Early	O
access	O
implementation	O
of	O
the	O
QVT-Core	O
language	O
was	O
in	O
OptimalJ	B-Language
version	O
3.4	O
from	O
Compuware	O
.	O
</s>
<s>
However	O
,	O
OptimalJ	B-Language
has	O
been	O
discontinued	O
.	O
</s>
<s>
QVT-Relations	O
:	O
</s>
<s>
Fully	O
compliant	O
with	O
QVT-Relations	O
language	O
.	O
</s>
<s>
Uses	O
QVT-Relations	O
syntax	O
,	O
but	O
deliberately	O
departs	O
from	O
the	O
semantics	O
of	O
the	O
OMG	O
standard	O
.	O
</s>
<s>
The	O
Eclipse	B-Application
M2M	I-Application
project	O
aims	O
to	O
produce	O
an	O
implementation	O
of	O
QVT	B-Language
Core	O
and	O
Relations	O
.	O
</s>
<s>
Echo	O
,	O
an	O
open-source	O
EMF-based	O
tool	O
for	O
model	O
repair	O
and	O
transformation	O
built	O
over	O
the	O
Alloy	B-Application
model	O
finder	O
,	O
which	O
provides	O
an	O
implementation	O
of	O
QVT-Relations	O
syntax	O
,	O
but	O
using	O
semantics	O
that	O
deliberately	O
depart	O
from	O
the	O
OMG	O
specification	O
.	O
</s>
<s>
QVT-Like	O
:	O
</s>
<s>
jQVT	O
:	O
A	O
compiled	O
QVT	B-Language
engine	O
for	O
Java	O
,	O
using	O
Xbase	O
in	O
place	O
of	O
OCL	B-Language
.	O
</s>
<s>
A	O
QVT-relational	O
transformation	O
is	O
first	O
compiled	O
into	O
Java	O
source	O
code	O
,	O
which	O
then	O
directly	O
produces	O
the	O
target	O
model	O
from	O
source	O
ones	O
at	O
run-time	O
,	O
without	O
interpreting	O
the	O
transformation	O
rule	O
again	O
.	O
</s>
<s>
Tefkat	B-Language
:	O
an	O
open	O
source	O
implementation	O
of	O
Tefkat	B-Language
language	O
which	O
is	O
also	O
similar	O
to	O
QVT	B-Language
.	O
</s>
<s>
ATL	B-Language
:	O
a	O
component	O
in	O
the	O
M2M	B-Application
Eclipse	O
project	O
.	O
</s>
<s>
ATL	B-Language
is	O
a	O
QVT-like	O
transformation	O
language	O
and	O
engine	O
with	O
a	O
large	O
user	O
community	O
and	O
an	O
open	O
source	O
library	O
of	O
transformations	O
.	O
</s>
<s>
Model	B-Language
Transformation	I-Language
Framework	O
(	O
MTF	O
)	O
:	O
an	O
IBM	O
alphaWorks	O
project	O
,	O
last	O
updated	O
in	O
2007	O
.	O
</s>
