Database Reference
In-Depth Information
Table 1. Instances of two export fuzzy relations
Faculty
:
DB
1
Name
Age
Health
Dept
Exp
Pay
IT
y old
3
y poor
1
y highT24
E
y highT24
P
y
2
mod
Datta
CS
3
3
T
u mid
2
u avrg
2
u
2
mod
u
2
mod
u
2
mod
John
CE
E
P
T
y mid
2
y
good
y low
E
y
2
mod
y highT24
T
Soma
MA
3
1
P
3
Emp
:
DB
2
y
old
y
poor
y
highT24
E
v
highT24
P
v
highT24
T
Datta
CS
33
11
33
16
17
v
old
v
poor
v
25
mod
y
highT24
P
y
highT24
T
Dhar
ME
22
23
E
32
24
v
old
v
good
y
highT24
E
v
36
mod
y
highT24
T
John
CE
32
33
33
P
24
v mid
42
v
good
y
highT24
E
y
highT24
P
v
lowT47
T
Mona
EC
43
33
32
47
v
old
v
avrg
v
55
mod
y
highT24
P
y
highT24
T
Ram
CS
52
53
E
32
24
y mid
22
y
good
y
13
mod
y
22
mod
y
31
mod
Soma
MA
32
E
P
T
At level-0 instance integration, export fuzzy database instances are not integrated at all although the
mapping from export fuzzy schemas to global fuzzy schema has been identified. It is necessary to at-
tach the source information to the export instances when they appear in the global fuzzy relations. For
example, consider the two export fuzzy relations
Emp
and
Faculty
as given in Table 1.
f
of fuzzy inclusion
dependencies between the two export fuzzy relations
Emp
and Faculty is not empty. This establishes
the fact that the two export fuzzy relations
Emp
and Faculty are related and hence can be integrated.
While integrating (at level-0) two databases, only the related relations are merged as illustrated in Table
2.
It has already been shown in (Sharma, Goswami and Gupta, 2004) that the set å
As shown in Table 2, we have assigned the (export fuzzy database identifier),
DB
1
, for instances that
come from the
Emp
relation in FRDB1, and assigned
DB
2
for instances that come from the
Faculty
in
FRDB2. Since we only have one export database for each local database, the export database identifier
can be treated as the local database identifier. In this way, we have extended the relational fuzzy data
model with an additional source attribute, and we call the relational data model with such extension the
Fuzzy Tuple Source (FTS) Relational data Model. Note that even when the fuzzy schemas of our two
export fuzzy relational database examples are compatible with the global schema, there may still be
