1
.
In
computer
science
,
ACID
(
Atomicity
,
____________________
,
Isolation
,
____________________
)
is
a
set
of
properties
that
guarantee
that
database
transactions
are
processed
reliably
.
In
the
context
of
databases
,
a
single
logical
operation
on
the
data
is
called
a
transaction
.
For
example
,
a
transfer
of
funds
from
one
bank
account
to
another
,
even
involving
multiple
changes
such
as
debiting
one
account
and
crediting
another
,
is
a
single
transaction
.
2
.
In
database
systems
,
atomicity
(
or
atomicness
;
from
Greek
a
-
tomos
,
undividable
)
is
one
of
the
ACID
transaction
properties
.
In
an
atomic
transaction
,
a
series
of
database
____________________
either
all
occur
,
or
nothing
occurs
.
3
.
Atomicity
does
not
behave
completely
____________________
with
regard
to
the
other
ACID
properties
of
the
transactions
.
For
example
,
isolation
relies
on
atomicity
to
roll
back
changes
in
the
event
of
isolation
failures
such
as
____________________
;
consistency
also
relies
on
rollback
in
the
event
of
a
consistency
-
violation
by
an
illegal
transaction
.
Finally
,
atomicity
itself
relies
on
durability
to
ensure
the
atomicity
of
transactions
even
in
the
face
of
external
failures
.
4
.
The
consistency
property
ensures
that
any
transaction
will
bring
the
database
from
one
____________________
state
to
another
.
Any
data
written
to
the
database
must
be
valid
according
to
all
defined
rules
,
including
but
not
limited
to
constraints
,
cascades
,
triggers
,
and
any
combination
thereof
.
5
.
The
isolation
property
ensures
that
the
concurrent
____________________
of
transactions
results
in
a
system
state
that
could
have
been
obtained
if
transactions
are
executed
serially
,
i
.
e
.
one
after
the
other
.
Each
transaction
has
to
execute
in
total
isolation
i
.
e
.
if
T1
and
T2
are
being
executed
concurrently
then
both
of
them
should
remain
unaware
of
each
other's
presence
.
