Databases Reference
In-Depth Information
δ
(Operation,
recipient
)=Recipient
δ
(Operation,
notes
)=Notes;
δ
(Operation,
value
)=Value
δ
(Account Operation,
@bankAccN
)=
q
fin
δ
(Account Operation,
@Id
)=
q
fin
δ
(Request,
@number
)=
q
fin
The schema automaton defined accepts the same paths allowed by the
considered DTD. Specifically,
L
(
M
G
) is equal to:
/account operation
,
/account operation/@Id
,
/account operation/@bankAccN
,
/account operation/request
,
/account operation/request/@number
,
/account operation/request/date
,
/account operation/request/means
,
/account operation/request/notes
,
/account operation/operation
,
/account operation/operation/type
,
/account operation/operation/amount
,
/account operation/operation/recipient
,
/account operation/operation/notes
,
/account operation/operation/value
.
The second step of the static
ana
lysis method consists in building the
access control automata
M
Γ
and
M
Γ
, for each of the three groups of users
considered. For the sake of simplicity, we represent only the language of the
automaton.
BankEmployee
L
(
M
Γ
)=
{
}·
(
Σ
E
)
∗
·
(
Σ
A
∪{
}
)
account operation
StatisticalAnalyst
L
(
M
Γ
)=
(
Σ
E
)
∗
(
Σ
A
{
}·
·
∪{
}
)
\
account operation
(
Σ
E
)
∗
·
(
Σ
A
{
notes
}·
∪{
}
)
Client
L
(
M
Γ
)=
∅·
(
Σ
E
)
∗
·
(
Σ
A
∪{
}
);
L
(
M
Γ
)=
{
}·
(
Σ
E
)
∗
·
account operation
(
Σ
A
∪{
}
)
Here,
is the set difference operator,
is the
nil character, and (
Σ
E
)
∗
represents any string in
Σ
E
.
Consider now the XQuery expression introduced in Example 2. The cor-
responding XPath expressions, classified on the basis of the clause they are
represented in, are:
·
is the concatenation operator,
\
FOR, LET, ORDER BY ,WHERE
:
/account operation
;
/account operation/operation/type
RETURN
:
account operation/operation/amount
;
account operation/operation/recipient
;
account operation//notes
Here
implies
both
and
record//notes
record/request/notes
record/operation/notes
.
On the basis of the static analysis, it is possible to classify the requests
submitted by users. As an example, consider the following requests.
•
BankEmployee
requests
/account operation/operation/type
: the re-
quest is
always granted
;
