Schema Translation - Information Systems Reengineering, Integration and Normalization - page 114

table in partial participation must address to the primary key of its parent table and
can be a null value. In DTD, we translate the total and partial participations into an
optional occurrence as shown in Figs. 3.43 and 3.44 .

Case 1: Total/Mandatory Participation

((50RGHO '7'*UDSK

$
$

$
$

(QWLW\$ (OHPHQW$

5

Q

6FKHPD

%
%

%
%

(QWLW\% (OHPHQW%

7UDQVODWLRQ

'7'

5HODWLRQDO6FKHPD

(/(0(17 $%!
$77/,67$$&'$7$5(48,5('!
$77/,67$$&'$7$5(48,5('!
(/(0(17 %(037<!
$77/,67%%&'$7$5(48,5('!
$77/,67%%&'$7$5(48,5('!

5HODWLRQ$ $ $
5HODWLRQ% % %$

Fig. 3.43 Schema translation of total participation

Case 2: Partial/Optional Participation

((50RGHO '7'*UDSK

$
$

$
$

(QWLW\$ (OHPHQW$

5

Q

6FKHPD

%
%

%
%

(QWLW\% (OHPHQW%

7UDQVODWLRQ

5HODWLRQDO6FKHPD '7'

5HODWLRQ$ $ $
5HODWLRQ% % %$

(/(0(17$ %!
$77/,67$$&'$7$5(48,5('!
$77/,67$$&'$7$5(48,5('!
(/(0(17%(037<!
$77/,67%%&'$7$5(48,5('!
$77/,67%%&'$7$5(48,5('!

1RWHIRUHLJQNH\QXOODEOH

Fig. 3.44 Schema translation of partial participation

Rule 4: Mapping Cardinality from RDB to DTD