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1\section{Functionality}
2\label{functionality}
3As described in the introduction, the \myprog{} software basically is a program which
4automatically derives an OBDA specification from a relational database schema,
5which then can be used by other tools to drive the actual bootstrapping process.
6Its functionality is described in the next section
7(while leaving out self-evident features) and is then listed completely
8in the section after that.
9
10\subsection{Description}
11The database schema is retrieved by connecting to an \name{SQL} database
12and querying its schema information.
13Parsing \name{SQL} specifications TODO or \name{SQL} dumps currently is not supported.
14%Naturally, authentication on the \name{SQL} server is supported, also by
15%interactively querying for passwords while hiding the typed input.
16The databases to derive information from can be specified by regular expressions,
17while there are also options to use other databases than specified or even
18other database servers, taken from a list of hard-coded strings.
19While these features may not seem to carry real benefit at the first glance,
20they proved to be very useful for testing purposes, especially since the retrieval of a
21database schema can take some time (see TODO).
22For the same purpose, \myprog{} allows the processing of a hard-coded example database schema.
23
24In addition to \osl{} output, a low-level output format containing information on all fields of
25the underlying objects is supported, which is useful for debugging
26(however, this feature has to be enabled via one slight change in the source code).
27To allow for some customization, the insertion of an own \osl{} header is supported
28(for more information on the \osl{} header, see the specification of the \osl{} language
29in section \ref{oslspec}).
30If the standard \osl{} header is used, it is by default loaded from a hard-coded copy,
31so bootstrapping information from a database server running locally or from the hard-coded
32example schema requires no Internet connection
33(simply inserting the \code{owl:imports} statement of course would not anyway,
34but the generated underlying ontology is always checked for consistency with the
35\osl{} header to prevent the generation of invalid output).
36
37The \myprog{} software can be used both in an interactive and in a non-interactive mode,
38while skipping a database or a database server or aborting the entire bootstrapping process
39is possible in either mode.
40Multiple database servers can be specified for a bootstrapping operation,
41which then are checked in order for a matching database,
42allowing to make use of mirrors or fallback servers.
43Additionally, multiple bootstrapping operations can be specified to be performed in sequence
44with one invocation of \myprog{}, while all features and settings previously described
45are enabled, disabled or set per operation.
46Finally, a help text can be displayed which describes the usage of \myprog{} including the
47description of all command-line arguments.
48
49\subsection{Summary}
50The functionality of the \myprog{} software can be summarized as follows:
51
52\begin{itemize}
53 \item Bootstrap one or more OBDA specifications from a database schema
54 by connecting to an \name{SQL} database server
55 \item Specify a custom port, login and password for the database server
56 \item Ask for passwords interactively (before starting any bootstrapping
57 operation), hide them if desired
58 \item Specify database names by regular expressions
59 \item Process an arbitrary database if the specified database
60 could not be found or unconditionally
61 \item Connect to a database server containing example databases
62 without having to specify any further details
63 \item Process a hard-coded example database schema
64 without having to specify any further details
65 \item Use the \osl{} format described in section \fullref{osl}
66 or a detailed low-level format for output
67 (the latter is for debugging purposes and has to be enabled
68 in the source code)
69 \item Write to standard output or to a file
70 \item Insert a custom \osl{} header
71 (see the specification of the OBDA Specification Language (\osl{})
72 in section \ref{oslspec} for details)
73 \item Consistency check against a custom \osl{} header
74 \item Consistency check against the standard \osl{} header without internet connection
75 \item Act interactively or non-interactively
76 \item Skip currently retrieved database (and try next on server),
77 skip current server or abort the overall process at any time, even in
78 non-interactive mode
79 \item Define multiple database servers to check in order for the specified database
80 \item Specify multiple bootstrapping operations to perform in order
81 \item Configure the features described in the above notes
82 per bootstrapping operation
83 \item Display a help text describing the usage of \myprog{},
84 including the description of all command-line arguments
85\end{itemize}