ISO/IEC JTC 1/SC34 N0227
ISO/IEC JTC 1/SC34
Information Technology --
Document Description and Processing Languages
Title: |
TMQL requirements (0.8.2) |
Source: |
TMQL Editors |
Project: |
Topic Map Query Language, ISO/IEC 18048 |
Project editor: |
Hans Holger Rath,
empolis GmbH Lars Marius Garshol,
Ontopia |
Status: |
Working Draft for comment |
Action: |
|
Date: |
12 June 2001 |
Summary: |
|
Distribution: |
SC34 and Liaisons |
Refer to: |
|
Supercedes: |
|
Reply to: |
Dr. James David Mason (ISO/IEC JTC1/SC34 Chairman) Y-12
National Security Complex Information Technology Services Bldg. 9113
M.S. 8208 Oak Ridge, TN 37831-8208 U.S.A. Telephone: +1 865
574-6973 Facsimile: +1 865 574-1896 E-mailk:
mailto:mxm@y12.doe.gov http://www.y12.doe.gov/sgml/sc34/sc34oldhome.htm
Ms. Sara Hafele, ISO/IEC JTC 1/SC 34 Secretariat American National
Standards Institute 11 West 42nd Street New York, NY 10036 Tel: +1
212 642 4976 Fax: +1 212 840 2298 E-mail:
shafele@ansi.org |
TMQL requirements (0.8.2)
Introduction
This document sets down the requirements that will guide the work with
the Topic Map Query Language (TMQL), a query language for topic maps. The
requirements herein presented document the intentions of the standards editors,
as informed by the user community. Its purpose is to make it clear what can be
expected to come out of the TMQL process, and to encourage the user community
to make their needs known to the editors.
This document has requirements for the TMQL standard as a whole, and
for the query part of TMQL in particular. Additional requirements for the
update part of TMQL will have to be defined at a later stage.
The following key words are used to indicate the degree of certainty
associated with each particular requirement:
- Shall
- Means that the requirement is absolute.
- Should
- Means that the requirement is a goal.
- May
- Means that the requirement is considered important, but that it is
not yet clear whether TMQL should conform to it or not.
Please note that some requirements are only implicitly specified
through the form of other requirements. This document must be read with care.
Feedback on this requirements document is requested.
Requirements in brief
This section contains the main TMQL requirements in summarized form for
easy reference.
- TMQL shall have a concise and human-readable syntax.
- TMQL shall be defined in terms of an abstract data model for topic
maps.
- TMQL query results shall be defined in terms of an abstract TMQL data
model.
- TMQL shall be independent of any particular interface between clients
and the query processor.
- TMQL shall support all natural languages equally well.
- The TMQL standard shall be defined in two parts, first one with
querying only, then one adding updates, provided ISO regulations allow.
- TMQL shall not unduly constrain the form of implementations.
- The TMQL standard shall be formal, fully define the processing of
queries, and, in so far as possible, be human-readable.
- TMQL shall be usable across a wide range of foreseeable platforms
over an extended lifetime (20-50 years).
Requirements in detail
General
The following general requirements apply, in addition to those already
mentioned.
- TMQL queries shall be able to span multiple topic maps.
- The TMQL standard should be defined based on a set of use cases
representing general classes of queries expected to be common.
- The TMQL standard shall define error situations, and how TMQL
processors should react to them.
- The TMQL language should be extensible. If it is extensible it shall
define controlled mechanisms for third-party extensions.
Syntax
The following requirements apply to the TMQL syntax, beyond those
stated above.
- The syntax shall be defined in terms of a formal grammar.
- The syntax should be designed so that queries expected to be common
be as compact as possible.
- An XML syntax for TMQL queries may be defined.
Model and algebra
The following requirements apply to the formal underpinnings of the
TMQL standard, beyond those already stated.
- TMQL shall not define its own data model, but be based on one common
to the entire family of topic map standards.
- TMQL may extend the common data model in order to be able to
represent query results which are not topic maps, but merely sets and lists of
topic map objects, resources, and perhaps also primitive values like strings
and numbers.
- The definition of TMQL should be based on an abstract query algebra,
which again should be based on the data model.
- The algebra may include operators such as: merge, comparison, sort,
boolean logic operators, set operators, matching by scope operators,
cardinality/count, and aggregation.
- TMQL may support returning associations, topic names, and occurrences
that were not present in the queried topic map(s).
Relationship to other standards
The TMQL standard is part of a larger family and community of
standards, and the following requirements apply to its integration in this
community.
- TMQL shall be based on ISO 13250.
- TMQL shall be based on the topic map data model currently being
defined. (Thus, TMQL will also support XTM.)
- URIs used in TMQL queries shall be normalized in the manner defined
by the topic map data model.
- If equality for topic map objects is not defined by the topic map
data model it must be defined by TMQL.
- TMQL shall relate to the Topic Map Conceptual Model through the topic
map data model.
- TMQL shall be harmonized with the Topic Map Constraint Language
currently being defined. It may be based on it.
- The character set of TMQL shall be Unicode.
- Ordering of strings in TMQL shall be based on externally-defined
specifications for internationalized string collation. Candidates are
the Unicode Collation
Algorithm, and ISO 14651
Specific query capabilities
This section lists some general classes of queries which TMQL may
support. The queries are only informally defined since there currently is no
data model to define them in terms of. This list has not been tested for
completeness.
Queries returning topics
- Find all topics with specific names whose scopes match a specific
scope.
- Find all topics with specific resources as occurrences whose scopes
match a specific scope.
- Find all topics playing one of a set of roles in an association of
one of a set of types whose scopes match a specific scope.
- Find all topics playing one of a set of roles in an association of
one of a set of types, where one of a set of topics plays one of a set of
roles, whose scopes match a specific scope.
- Find the topic that has a specific resource as one of its subject
indicators.
- Find the topic that has a specific resource as its subject
address.
- Find all topics that play one of a set of roles in instances of one
of a set of association types.
Queries returning associations
- Find all associations whose scopes match a specific scope.
- Find all associations that are instances of a specific type.
- Find all associations where one of a set of topics play any role, and
whose scopes match a specific scope.
- Find all associations where one of a set of topics play one of a set
of roles, and whose scopes match a specific scope.
Queries returning any topic map object
- Find the object that has a specific resource as its source
locator.
- Find all objects that are direct instances of a specific type.
- Find all objects that are instances of a specific type or any of its
subtypes.
Queries returning various types of objects
- Find all the names of the topics in a particular set of topics, whose
scopes match a particular scope.
- Find all the occurrences of the topics in a particular set of topics,
whose scopes match a particular scope.
- Find all the resources that are subject indicators of the topics in a
particular set of topics.
- Find the resources that are the addressable subjects of the topics in
a particular set of topics.
Non-Requirements
Requirements listed in this section are for various reasons not in the
scope of TMQL.
- The TMQL standard shall not include an API to query processors in
parts 1 or 2 of the standard. One may be defined in later parts.
- The TMQL standard shall not define mechanisms for specifying validity
constraints on topic maps. It may be used by other specifications and software
to define such constraints.
- The TMQL standard shall not define a natural language query
interface.
Acknowledgements
This document is based on input from