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[u/philim/db2osl_thesis.git] / program_functionality.tex
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1\section{Functionality}
2\label{functionality}
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3As described in the \hyperref[intro]{introduction} of this thesis,
4the \myprog{} software is
5a program automatically deriving an OBDA specification
6from a relational database schema,
c31df1ed 7which then can be used by other tools to drive the actual bootstrapping process.
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8Its functionality is described in this section,
9leaving out self-evident features, and is then listed completely.
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10How this functionality is exposed to users is described in Section~\fullref{interface}.
11The bootstrapping process using direct mapping as the core functionality
12of the software is described in Section~\ref{dirm}.
13
002fa020 14TODO: reference to OBDA topics
c31df1ed 15
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16The database schema is retrieved by connecting to an \name{SQL} database
17and querying its schema information.
002fa020 18Parsing \name{SQL} scripts or \name{SQL} dumps currently is not supported.
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19%Naturally, authentication on the \name{SQL} server is supported, also by
20%interactively querying for passwords while hiding the typed input.
21The databases to derive information from can be specified by regular expressions,
22while there are also options to use other databases than specified or even
23other database servers, taken from a list of hard-coded strings.
24While these features may not seem to carry real benefit at the first glance,
002fa020 25they proved to be useful for testing purposes, especially since the retrieval of a
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26database schema can take some time TODO (see Section~\fullref{stats}).
27For the same purpose, \myprog{} allows the processing of a hard-coded
28example database schema.
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30In addition to \osl{} output, a low-level output format containing information on all
31fields of the underlying objects is supported, which is useful for debugging
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32(however, this feature has to be enabled via one slight change in the source code).
33To allow for some customization, the insertion of an own \osl{} header is supported
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34(for more information on the \osl{} header, see the specification of the \osllong{}
35in Section~\ref{osl_spec}).
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36If the standard \osl{} header is used, it is by default loaded from a hard-coded copy,
37so bootstrapping information from a database server running locally or from the hard-coded
38example schema requires no Internet connection
39(simply inserting the \code{owl:imports} statement of course would not anyway,
40but the generated underlying ontology is always checked for consistency with the
41\osl{} header to prevent the generation of invalid output).
42
43The \myprog{} software can be used both in an interactive and in a non-interactive mode,
44while skipping a database or a database server or aborting the entire bootstrapping process
45is possible in either mode.
46Multiple database servers can be specified for a bootstrapping operation,
47which then are checked in order for a matching database,
48allowing to make use of mirrors or fallback servers.
49Additionally, multiple bootstrapping operations can be specified to be performed in sequence
50with one invocation of \myprog{}, while all features and settings previously described
51are enabled, disabled or set per operation.
52Finally, a help text can be displayed which describes the usage of \myprog{} including the
53description of all command-line arguments.
54
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55The functionality of the \myprog{} software can be summarized as follows:
56
57\begin{itemize}
58 \item Bootstrap one or more OBDA specifications from a database schema
59 by connecting to an \name{SQL} database server
60 \item Specify a custom port, login and password for the database server
61 \item Ask for passwords interactively (before starting any bootstrapping
62 operation), hide them if desired
63 \item Specify database names by regular expressions
64 \item Process an arbitrary database if the specified database
65 could not be found or unconditionally
66 \item Connect to a database server containing example databases
67 without having to specify any further details
68 \item Process a hard-coded example database schema
69 without having to specify any further details
b96bb723 70 \item Use the \osl{} format described in Chapter~\fullref{osl}
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71 or a detailed low-level format for output
72 (the latter is for debugging purposes and has to be enabled
73 in the source code)
74 \item Write to standard output or to a file
75 \item Insert a custom \osl{} header
b96bb723 76 (see the specification of the \oslboth{} in Section~\ref{osl_spec} for details)
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77 \item Consistency check against a custom \osl{} header
78 \item Consistency check against the standard \osl{} header without internet connection
79 \item Act interactively or non-interactively
80 \item Skip currently retrieved database (and try next on server),
81 skip current server or abort the overall process at any time, even in
82 non-interactive mode
83 \item Define multiple database servers to check in order for the specified database
84 \item Specify multiple bootstrapping operations to perform in order
85 \item Configure the features described in the above notes
86 per bootstrapping operation
87 \item Display a help text describing the usage of \myprog{},
88 including the description of all command-line arguments
89\end{itemize}