<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
in	O
the	O
field	O
of	O
databases	O
,	O
read	B-General_Concept
–	I-General_Concept
write	I-General_Concept
conflict	I-General_Concept
,	O
also	O
known	O
as	O
unrepeatable	B-General_Concept
reads	I-General_Concept
,	O
is	O
a	O
computational	O
anomaly	O
associated	O
with	O
interleaved	O
execution	O
of	O
transactions	O
.	O
</s>
<s>
However	O
,	O
when	O
T1	O
reads	O
from	O
A	O
,	O
it	O
discovers	O
two	O
different	O
versions	O
of	O
A	O
,	O
and	O
T1	O
would	O
be	O
forced	O
to	O
abort	B-General_Concept
,	O
because	O
T1	O
would	O
not	O
know	O
what	O
to	O
do	O
.	O
</s>
<s>
Strict	B-Operating_System
two-phase	I-Operating_System
locking	I-Operating_System
(	O
Strict	B-Operating_System
2PL	I-Operating_System
)	O
or	O
Serializable	O
Snapshot	O
Isolation	O
(	O
SSI	O
)	O
prevent	O
this	O
conflict	O
.	O
</s>
<s>
This	O
is	O
a	O
typical	O
read-write	B-General_Concept
conflict	I-General_Concept
situation	O
.	O
</s>
