Data Conversion - Information Systems Reengineering, Integration and Normalization - page 170

Case 1: One-to-One Cardinality (Fig. 4.16 )

Relation A
A1
a11
a12

XMLDocument

A2
a21
a22

<A A1="a11" A2="a21">
<B B1="b11"B2="b21"></B>
</A>

Data

Relation B
B1
b11

Conversion

B2
b21

*A1
a11

<A A1="a12" A2="a22">
<B B1="b12"B2="b22"></B>
</A>

b12 b22 a12

Fig. 4.16 One-to-one cardinality: data conversion

Case 2: One-to-Many Cardinality (Fig. 4.17 )

RelationA
A1
a11
a12

XMLDocument

A2
a21
a22

<A A1="a11" A2="a21">
<B B1="b11" B2="b21"></B>
</A>

Data

RelationB
B1
b11

Conversion

B2
b21

*A1
a11

<A A1="a12" A2="a22">
<B B1="b12" B2="b22"></B>
<B B1="b13" B2="b23"></B>
</A>

b12 b22 a12

b13 b23 a12

Fig. 4.17 One-to-many cardinality: data conversion

Case 3: Many-to-Many Cardinality (Fig. 4.18 )

Relation A
A1
a11
a12

XMLDocument

A2
a21
a22

<A A1="a11"A2="a21" A_id="1"></A>
<B B1="b11" B2="b21" B_id="2"></B>
<R A_idref="1" B_idref="2"></R>

Relation B
B1
b11

Data

B2
b21

<A A1="a12"A2="a22" A_id="3"></A>
<B B1="b12" B2="b22" B_id="4"></B>
<R A_id="3"B_idref="4"></R>

Conversion

b12 b22

Relation R
* A1
a11

* B1
b11

a12 b12