<s>
An	O
event	B-General_Concept
store	I-General_Concept
is	O
a	O
type	O
of	O
database	O
optimized	O
for	O
storage	O
of	O
events	O
.	O
</s>
<s>
Conceptually	O
,	O
in	O
an	O
event	B-General_Concept
store	I-General_Concept
,	O
only	O
the	O
events	O
of	O
a	O
dossier	O
or	O
policy	O
are	O
stored	O
.	O
</s>
<s>
In	O
an	O
event	B-General_Concept
store	I-General_Concept
database	O
,	O
this	O
means	O
that	O
all	O
objects	O
that	O
should	O
be	O
instantiated	O
,	O
are	O
not	O
stored	O
in	O
the	O
database	O
.	O
</s>
<s>
shown	O
in	O
a	O
user	B-Application
interface	I-Application
)	O
,	O
the	O
instantiated	O
objects	O
are	O
removed	O
from	O
memory	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
event	B-General_Concept
store	I-General_Concept
concept	O
of	O
a	O
database	O
can	O
be	O
applied	O
to	O
insurance	O
policies	O
or	O
pension	O
dossiers	O
.	O
</s>
<s>
A	O
crucial	O
part	O
of	O
an	O
event	B-General_Concept
store	I-General_Concept
database	O
is	O
that	O
each	O
event	O
has	O
a	O
double	O
timeline	B-Application
:	O
This	O
enables	O
event	B-General_Concept
stores	I-General_Concept
to	O
correct	O
errors	O
of	O
events	O
that	O
have	O
been	O
entered	O
into	O
the	O
event	B-General_Concept
store	I-General_Concept
database	O
before	O
.	O
</s>
<s>
Another	O
crucial	O
part	O
of	O
an	O
event	B-General_Concept
store	I-General_Concept
database	O
is	O
that	O
events	O
that	O
are	O
stored	O
are	O
not	O
allowed	O
to	O
be	O
changed	O
.	O
</s>
<s>
The	O
only	O
way	O
to	O
change	O
(	O
or	O
better	O
:	O
correct	O
)	O
these	O
events	O
is	O
to	O
instantiate	O
a	O
new	O
event	O
with	O
the	O
new	O
values	O
and	O
using	O
the	O
double	O
timeline	B-Application
.	O
</s>
<s>
One	O
advantage	O
of	O
the	O
event	B-General_Concept
store	I-General_Concept
concept	O
is	O
that	O
handling	O
the	O
effects	O
of	O
back	O
dated	O
events	O
(	O
events	O
that	O
take	O
effect	O
before	O
previous	O
events	O
and	O
that	O
may	O
even	O
invalidate	O
them	O
)	O
is	O
much	O
easier	O
.	O
</s>
<s>
An	O
event	B-General_Concept
store	I-General_Concept
will	O
simplify	O
the	O
code	O
in	O
that	O
rolling	O
back	O
erroneous	O
situations	O
and	O
rolling	O
up	O
the	O
new	O
,	O
correct	O
situations	O
is	O
not	O
needed	O
anymore	O
.	O
</s>
<s>
In	O
an	O
event	B-General_Concept
store	I-General_Concept
,	O
only	O
the	O
new	O
event	O
(	O
and	O
its	O
corresponding	O
facts	O
)	O
are	O
stored	O
.	O
</s>
