<s>
VMDS	B-Application
abbreviates	O
the	O
relational	O
database	O
technology	O
called	O
Version	O
Managed	O
Data	O
Store	O
provided	O
by	O
GE	O
Energy	O
as	O
part	O
of	O
its	O
Smallworld	O
technology	O
platform	O
and	O
was	O
designed	O
from	O
the	O
outset	O
to	O
store	O
and	O
analyse	O
the	O
highly	O
complex	O
spatial	O
and	O
topological	O
networks	O
typically	O
used	O
by	O
enterprise	O
utilities	O
such	O
as	O
power	O
distribution	O
and	O
telecommunications	O
.	O
</s>
<s>
VMDS	B-Application
was	O
originally	O
introduced	O
in	O
1990	O
as	O
has	O
been	O
improved	O
and	O
updated	O
over	O
the	O
years	O
.	O
</s>
<s>
VMDS	B-Application
has	O
been	O
designed	O
as	O
a	O
spatial	B-Algorithm
database	I-Algorithm
.	O
</s>
<s>
This	O
gives	O
VMDS	B-Application
a	O
number	O
of	O
distinctive	O
characteristics	O
when	O
compared	O
to	O
conventional	O
attribute	O
only	O
relational	O
databases	O
.	O
</s>
<s>
VMDS	B-Application
is	O
composed	O
of	O
two	O
parts	O
:	O
a	O
simple	O
,	O
highly	O
scalable	O
data	O
block	O
server	O
called	O
SWMFS	O
(	O
Smallworld	O
Master	O
File	O
Server	O
)	O
and	O
an	O
intelligent	O
client	O
API	B-Application
written	O
in	O
C	B-Language
and	O
Magik	B-Language
.	O
</s>
<s>
This	O
approach	O
makes	O
VMDS	B-Application
well	O
suited	O
to	O
enterprise	O
deployment	O
that	O
might	O
involve	O
hundreds	O
or	O
even	O
thousands	O
of	O
concurrent	O
clients	O
.	O
</s>
<s>
Relational	O
databases	O
support	O
short	B-General_Concept
transactions	I-General_Concept
in	O
which	O
changes	O
to	O
data	O
are	O
relatively	O
small	O
and	O
are	O
brief	O
in	O
terms	O
in	O
duration	O
(	O
the	O
maximum	O
period	O
between	O
the	O
start	O
and	O
the	O
end	O
of	O
a	O
transaction	O
is	O
typically	O
a	O
few	O
seconds	O
or	O
less	O
)	O
.	O
</s>
<s>
VMDS	B-Application
supports	O
long	O
transactions	O
in	O
which	O
the	O
volume	O
of	O
data	O
involved	O
in	O
the	O
transaction	O
can	O
be	O
substantial	O
and	O
the	O
duration	O
of	O
the	O
transaction	O
can	O
be	O
significant	O
(	O
days	O
,	O
weeks	O
or	O
even	O
months	O
)	O
.	O
</s>
<s>
To	O
cope	O
with	O
this	O
scenario	O
VMDS	B-Application
has	O
inbuilt	O
support	O
for	O
automatically	O
managing	O
such	O
conflicts	O
and	O
allows	O
applications	O
to	O
review	O
changes	O
and	O
accept	O
only	O
those	O
edits	O
that	O
are	O
correct	O
.	O
</s>
<s>
As	O
well	O
as	O
conventional	O
relational	O
database	O
features	O
such	O
as	O
attribute	O
querying	O
,	O
join	O
fields	O
,	O
triggers	O
and	O
calculated	O
fields	O
,	O
VMDS	B-Application
has	O
numerous	O
spatial	O
and	O
topological	O
capabilities	O
.	O
</s>
<s>
Spatial	O
functions	O
include	O
:	O
find	O
all	O
features	O
within	O
a	O
polygon	O
,	O
calculate	O
the	O
Voronoi	B-Architecture
polygons	I-Architecture
of	O
a	O
set	O
of	O
sites	O
and	O
perform	O
a	O
cluster	B-Algorithm
analysis	I-Algorithm
on	O
a	O
set	O
of	O
points	O
.	O
</s>
<s>
Network	O
analysis	O
engines	O
are	O
provided	O
to	O
answer	O
questions	O
such	O
as	O
find	O
the	O
shortest	O
path	O
between	O
two	O
nodes	O
or	O
how	O
to	O
optimize	O
a	O
delivery	O
route	O
(	O
the	O
travelling	B-Algorithm
salesman	I-Algorithm
problem	I-Algorithm
)	O
.	O
</s>
<s>
In	O
VMDS	B-Application
all	O
data	O
is	O
presented	O
to	O
the	O
application	O
as	O
objects	O
.	O
</s>
<s>
This	O
is	O
different	O
from	O
many	O
relational	O
databases	O
that	O
present	O
the	O
data	O
as	O
rows	O
from	O
a	O
table	O
or	O
query	O
result	O
using	O
say	O
JDBC	B-Language
.	O
</s>
<s>
VMDS	B-Application
provides	O
a	O
data	O
modelling	O
tool	O
and	O
underlying	O
infrastructure	O
as	O
part	O
of	O
the	O
Smallworld	O
technology	O
platform	O
that	O
allows	O
administrators	O
to	O
associate	O
a	O
table	O
in	O
the	O
database	O
with	O
a	O
Magik	B-Language
exemplar	O
(	O
or	O
class	O
)	O
.	O
</s>
<s>
Magik	B-Language
get	O
and	O
set	O
methods	O
for	O
the	O
Magik	B-Language
exemplar	O
can	O
be	O
automatically	O
generated	O
that	O
expose	O
a	O
table	O
's	O
field	O
(	O
or	O
column	O
)	O
.	O
</s>
<s>
Each	O
VMDS	B-Application
row	O
manifests	O
itself	O
to	O
the	O
application	O
as	O
an	O
instance	O
of	O
a	O
Magik	B-Language
object	O
and	O
is	O
known	O
as	O
an	O
RWO	O
(	O
or	O
real	O
world	O
object	O
)	O
.	O
</s>
