Database Reference
In-Depth Information
If (t
i(temp)
= p)
{
IF (t
i
[TC]
≻
L(user))
{
Mark to be deleted by high user.
i = i+1
}
Else
{
t
i
[A
i
] = E(K, a
i
)
Update ti
}
i = i +1
}
Else
{
i = i+1
}
The UPDATE statement is permitted if the database state satisfies
the entity integrity, the foreign key integrity, and the referential
integrity properties.
6.4.5 he UPLEVEL Statement
The UPLEVEL statement executed by a user with security class level
L has the following general form [82]:
UPLEVEL R GET [A
1
, A
2
, ..., A
n
] FROM [C
1
, C
2
, ..., C
n
]
WHERE P
where R is the relation,
A
1
,A
2
,...,A
n
are the data attributes,
C
1
,C
2
,
...,C
n
are the security classification levels for
A
1
,
A
2
,
...,
A
n
,
and P is a predicate that may include conditions that define the tuples
that should be upleveled.
C
i
= L(user)
K = KCi
For 1≤i≤n
IF (t
i
[TC] = L(user))
{
t
i(temp)
= D(K, E(K, t
i
))
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