Database Reference
In-Depth Information
Fig. 6.2
Synchronization
Definition 39
A Universal general purpose programming language machine
M
U
is an
RMI
=
(S
U
, Oper
U
, Te s t
U
, In
U
, In
EU
, Out
U
),
with the following features:
1. The operations COMMIT, ROLLBACK, CALL
n
∈
Oper
U
are used to execute
the Application Plans in
M
R
. NOP
∈
Oper
U
is the operation which does not
change the state of the machine.
2.
x
1
is the register for synchronization. Its default value (imposed by the initial
state
st
0
) is equal to 0. This value is changed in the following cases:
•
Imposed to 1 after an execution of the statement COMMIT;
•
Imposed to 2 after an execution of the statement ROLLBACK;
+
k
after an execution of the statement CALL
k
(for
k
th embed-
ded, compiled by Bind SQL statement, program
P
k
in the Application Plane
of
M
R
).
3.
x
2
is the register for the error condition received from
M
R
. Its default value
(imposed by the initial state
st
0
) is equal to 0. This value is changed by the
function
In
∗
EU
(see the next point) and is also imposed to 0 after an execution of
one of the operators described in the point 1 above.
4. The extended input function
In
∗
EU
satisfies the following properties:
•
Imposed to 2
a function
f
:
S
U
→
S
U
if
z
=
(n,m,R)
∈
INP
;
λIn
∗
EU
(z)
=
identity function
, id
:
S
U
→
S
U
otherwise
,
