Schema Translation - Information Systems Reengineering, Integration and Normalization - page 115

a child table in a one-to-many occurrence. Many-to-many cardinality indicates that
a primary key of a parent table is addressed by many foreign keys of a child table
and vice versa. This pair of tables are thus in a many-to-many cardinality. In DTD,
we translate one-to-one cardinality into parent and child element (Fig. 3.45 ) and
one-to-many cardinality into a parent and child element with multiple occurrences
(Fig. 3.46 ). In many-to-many cardinality, it is mapped into DTD of a hierarchy
structure with ID and IDREF as shown in Fig. 3.47 .

Case 1: One-to-One Cardinality

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Fig. 3.45 Schema translation of one-to-one cardinality

Case 2: One-to-Many Cardinality

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