SEKE 2012 Proceedings - Knowledge Systems Institute

Institution (cod_institution, city, state, name, department);
Paper (cod_paper, title, cod_institution), cod_institution references
Institution;
Writer (cod_writer, name, code, e_mail, age);
Conference (cod_conference, day, title, city, state);
PaperWriter (cod_paper, cod_writer), cod_paper references Paper
and cod_writer references Writer;
ConferencePaper (cod_conference, cod_paper), cod_conference
references Conference and cod_paper references Paper;
is done into a table, as shown in element (line 14);
the table name is the element (line 15).
Figure 6. Mapping file
Figure 5. Global OWL Ontology
Basically the non-lexical concepts are mapped to tables,
as well as the N:N relationships. The lexical concepts
are mapped to columns in the corresponding tables. The
columns whose cardinality is 1 become not null in the
DB. Details of this mapping are described in [6].
4.2 Mapping Document
In order to describe and track the equivalences between
concepts from the XML files, the ontology and the relational
schema, we have defined a structured artifact named
mapping document, as shown in Figure 6.
To explain the involved transformations for storing the
input XML data into the relational schema, the mapping
process represents the ontology concepts with the element
(line 3). According to the existing concept
in the global ontology, the XML data sources are identified
by the id attribute of the element (line 4).
The XML content is pointed by the XPath expression in
the element (line 5). If an XML source
content has not refered to a certain ontology concept, the
element is empty.
The element (line 13) indicates where
the data will be stored. For non-lexical concepts, the storage
For lexical concepts, the element has
two internal elements, indicating that the information is
stored into a column. From line 28 on, it is described
that the concept title specified on line 18 is stored as
a column (line 29), whose name is title (line 30) in
conference table (line 31). In this case, it is a lexical
concept represented by a string (line 32).
We used the mapping file presented in Figure 6 for generating
the insert statements. The mapping document is an essential
mechanism that allows specifying the equivalences
between the XML data, the ontology and the relational
schema. For better understanding, only conference e
title concepts were demonstrated. The mapping document
generation is implemented by a semi-automatic tool
named CMap (Concept Mapper).
5 Conflict Classification and Resolution
To store original XML data into the RDB, several conflicts
have to be detected and solved. Because of space issues,
we describe in details only the naming conflicts. Other
conflicts are just mentioned in the end of this section. The
original work (master thesis [5]) describes the full set of
conflicts, as well as all the proposed algorithms, the implementation
and the tests that deal with those conflicts.
The naming conflicts refers to naming inconsistencies in
XML documents. There are two types of naming conflicts:
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