The editors thank the Japanese body for its feedback and apologize for this delayed
response.
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The Topic Map Query Language (TMQL) is an extension of Structured Query Language (SQL) and
Object Query Language (OQL), a query language allowing users to access data in Topic Maps
Data Model. TMQL should focus on extending SQL regarding the select-expression language
part.
While TMQL allows to use an SQL-like syntax, it is NOT designed as an extension of SQL, but
instead as a dedicated query language. This implies that its design revolves around the
data model for TMs, not the data model SQL was originally designed for.
The conceptual problems SQL has when extended to include XML processing may serve as warning sign
here.
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It needs also to extend OQL regarding the tuple-expression language part and the tm-content
language part and regarding additional programming support like path epressions.
It is unclear to the editors why TMQL should orient itself towards a language which is not
used at all (OQL). Also the TMDM is not an object-oriented model.
The editors welcome a clarification what extensions particularily should be added to the
current TMQL draft. TMQL already has an elaborate path expression language rendering tuple
results.
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Finally TMQL should consider to follow existing XML query language regarding the xml-content
query language part.
The current draft already has included an XQuery-like query structure following a FLWR
syntax. This structure not only allows to generate conveniently XML-formed results, but also
Topic Map-formed results.
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It is important that the types of data access for Topic Maps, Information retrieval (IR) and
information filtering can be supported by the wide number of applications following and
extending existing standards such SQL, OQL, XQUERY...
If the Japanese national body refers to the range of supported applications, the baseline
has been outlined by the TMQL Use
Cases document.
If the Japanese national body by this means that it is important for TMQL to be
implementable on top of SQL, OQL, or XQuery repositories, the editors wholeheartedly
agree. While this was never stated as an official requirement, there is general agreement
about this among the editors and in the committee. Feedback on TMQL features which endanger
this goal would be very much welcome.
If the editors have misunderstood the intent of this comment clarification is requested.
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Thus the current proposal needs to be updated and revisited accordingly. The major risk is
that TMQL might become too complicated to be wildly used and accepted by a large number of
applications.
The editors feel that supporting a large number of applications and low language
complexity are conflicting design goals. In that we agree that adding or removing a
particular language feature has to be considered carefully.
If the Japanese national body feels that any specific functionality is too complex to
implement, and should be removed, explicit feedback on this would be welcome. It would also
be appreciated if a rationale for the suggested removals could be given.
