Database Reference
In-Depth Information
expression that may include conditions involving classification attri-
butes.
t
i(temp)
is a temporary tuple for the decrypted data during the
execution of the delete statement.
D(K,E(K,t
i
))
is the decryption of
the encrypted data value in the tuple
t
i
by a symmetric encryption key.
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
))
If (t
i(temp)
= p)
{
Delete ti
}
i = i +1
}
Else IF (t
i
[TC]
≻
L(user))
{
Mark to be deleted by high user.
i = i+1
}
Else
{
i = i+1
}
The DELETE statement is permitted if the database state satisfies the
entity integrity, the foreign key integrity, and the referential integrity
properties.
6.4.3 he SELECT Statement
The SELECT statement executed by a user with security class level L
has the following general form [82]:
SELECT [A
1
,A
2
,...,A
n
] FROM R
WHERE P
where R is the relation name, [
A
1
,A
2
,...,A
n
] are the attributes names,
and P is a predicate expression that may include conditions involving
the security classification attributes.
ti
(temp)
is a temporary tuple for
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