\addtolength{\textwidth}{2.0cm}
\addtolength{\topmargin}{-1.0cm}
-\newcommand{\MathQL}{\textsc{mathql-1}}
-\newcommand{\RDF}{\textsc{rdf}}
-\newcommand{\RDFS}{\textsc{rdf schema}}
-\newcommand{\HELM}{\textsc{helm}}
-\newcommand{\POSIX}{\textsc{posix}}
-\newcommand{\XML}{\textsc{xml}}
-\newcommand{\CAML}{\textsc{caml}}
-\newcommand{\SQL}{\textsc{sql}}
-\newcommand{\PostgreSQL}{\textsc{postgresql}}
-\newcommand{\Galax}{\textsc{galax}}
-\newcommand{\XQuery}{\textsc{xquery}}
+\newcommand\xcomment[1]{}
+\newcommand\URI[1]{\texttt{<#1>}}
+
+\newcommand\MathQL{\textsc{mathql-1}}
+\newcommand\RDF{\textsc{rdf}}
+\newcommand\RDFS{\textsc{rdf schema}}
+\newcommand\HELM{\textsc{helm}}
+\newcommand\POSIX{\textsc{posix}}
+\newcommand\XML{\textsc{xml}}
+\newcommand\CAML{\textsc{caml}}
+\newcommand\SQL{\textsc{sql}}
+\newcommand\MySQL{\textsc{mysql}}
+\newcommand\PostgreSQL{\textsc{postgresql}}
+\newcommand\Galax{\textsc{galax}}
+\newcommand\XQuery{\textsc{xquery}}
\title{MathQL-1.4}
\author{Ferruccio Guidi}
+\bibliographystyle{numeric}
+
\begin{document}
\maketitle
-\section{Overview}
-
-{\MathQL} is a query language for {\RDF} databases, developed in the context
-of the {\HELM} project. Its name suggests that it is supposed to be the first
-of a group of query languages for retrieving information from distributed
-digital libraries of formal mathematical knowledge, but no other languages of
-this group have been implemented yet except for {\MathQL} that is not
-Mathematics-oriented. So the name is a bit misleading.
-
-{\MathQL} is carefully designed for having the following features:
-
-\begin{enumerate}
-
-\item
-compliance with the main requirements stated by the {\RDF} community;
-
-\item
-native support for post-processing the query results;
-
-\item
-{\HELM}-independent implementation of the query engine.
-
-\end{enumerate}
-
-We will briefly analyze these features in the remaining part of this section.
-
-\subsubsection*{The main requirements from the RDF community}
-
-As a query language for {\RDF} databases, {\MathQL} has a well-conceived
-semantics, defined in term of an abstract metadata model, according to which
-queries return exhaustive solutions.
-The language provides facilities for imposing query constraints based on
-{\RDFS} and for the traversal of compound values of properties.
-It also provides a full set of Boolean operators to compose the query
-constraints and facilities for selecting resources or literals by means of
-{\POSIX} regular expressions.
-Moreover the language allows to customize the query results specifying what
-part of a solution should be preserved, and supports a machine-processable
-{\XML} syntax as well as a human-readable textual syntax to achieve the best
-usability.
-
-The two syntaxes concern both queries and results, making {\MathQL} usable in
-a distributed environment where query engines are implemented as stand-alone
-components. This is because in this setting both queries and query results
-must be exchanged by the system's components and thus need to be encoded in
-clearly defined format.
-
-{\MathQL} provides a graph-oriented access to the {\RDF} metadata, based on
-tree instantiation.
-This approach has the advantage of providing an abstraction over the
-concrete representation of the {\RDF} database (that can consist of {\RDF}
-triples and {\XML} files simultaneously) at the user level, and this is
-definitely desirable especially in a distributed context.
-
-{\MathQL} query results are meant to capture the structure of trees coming
-from an {\RDF} graph and for this purpose a standard $1$- or $2$-dimensional
-organization (as provided by most {\RDF}-oriented query languages) is not
-satisfactory. Here {\MathQL} approach is to use a $4$-dimensional organization
-for its query results.
-
-\subsubsection*{Post-processing and code generation capabilities}
-
-The {\MathQL} query engine, that is written in {\CAML} for an easy integration
-with the {\HELM} software, provides two ways of processing the query results:
-at {\CAML} side and natively.
-
-At {\CAML} side, an application issues a query calling a function of the
-engine and manipulates the result either operating directly on its internal
-representation (that is placed in the public scope), or using a set of
-dedicated functions specifically designed to manage the query results.
-This set of functions includes a basic library but is extensible depending
-on the {\CAML} modules included in the engine at compile-time. In this way
-an expert user can write a {\CAML} module with new dedicated functions and can
-include it in the engine recompiling it.
-
-{\MathQL} supports native post-processing of the query results including the
-standard constructions of an imperative Turing-complete programming language,
-whose aim is definitely not that of being all-purpose (the user can work at
-{\CAML} side for that), but of being optimized for the management of the
-query results.
-In this context an {\SQL}-like ``select-from-where'' construction is provided
-(as required by the {\RDF} community) as well as a mechanism for accessing the
-post-processing dedicated functions available to the engine.
-
-Moreover the language provides access to an extensible set of code-generating
-functions (also available at {\CAML} side) that the expert user can define
-writing suitable {\CAML} modules for the engine.
-Note that the generated code is always {\MathQL} code.
-
-The code generation features allow to build complex queries incrementally and
-in an automatic manner, as required by the needs of the {\HELM} project.
-Using the native programming language, instead, queries can include the
-post-processing algorithms on their results so the querying code and the
-subsequent processing code (if needed) are treated together as a
-self-contained object that can be computed by a single engine.
-In this sense the alternative of performing a complex query on a remote
-component issuing some {\MathQL} querying code followed by some {\CAML}
-post-processing code is really infeasible in a distributed context.
-
-\subsubsection*{Physical organization of the RDF database}
-
-The implementation of the {\MathQL} query engine does not depend on any
-software developed within the {\HELM} project, nor it depends on the {\HELM}
-metadata model in any way.
+\tableofcontents
-However the engine does make few assumptions on the way metadata are
-physically organized and needs some user-provided knowledge about the concrete
-metadata representation.
-Metadata stored as {\RDF} triples are accessed through a {\PostgreSQL} engine,
-while metadata stored as {\RDF}/{\XML} files are accessed through a {\Galax}
-{\XQuery} engine.
+\input{mathql_overview}
+\input{mathql_introduction}
+\input{mathql_bib}
\end{document}
projects / helm.git / blobdiff