eqtusersguide.tex

Emdros is a text database middleware-layer aimed at storage and retrieval of "text plus information

{\bf Stop}\ \includegraphics[scale=0.5]{stop.png}\ :
Stops the current execution.  You may have to wait a bit before the
execution stops.  Please try pressing this button again if execution
does not stop immediately.




\subsubsection{Menus}



There are four menus, each explained on its own page:


\begin{enumerate}

  
\item File menu

  
\item Edit menu

  
\item Tools menu

  
\item Help menu

\end{enumerate}



\paragraph{File menu}

\paragraph{New...}




The "New..." menu item clears the input
area and the output
area, thus "starting afresh".




Equivalent toolbar button:
\includegraphics[scale=0.5]{new.png}.


\paragraph{Open}




The "Open" menu item opens a file and reads it into the
input area.




The file can be either an MQL query or a configuration file.





Equivalent toolbar button:
\includegraphics[scale=0.5]{open.png}.


\paragraph{Save}




The "Save" menu item saves the current contents of the input area.  If no filename has been given
previously, the "Save As" dialog box will appear so you can give the
file a name.



Equivalent toolbar button:
\includegraphics[scale=0.5]{save.png}.


\paragraph{Save as}




The "Save as" menu item saves the current contents of the input
area, giving it a (new) name.




Equivalent toolbar button:
None.


\paragraph{Exit}




The "Exit" menu item quits the program.




Equivalent toolbar button:
None.



\paragraph{Edit menu}

\paragraph{Copy}




The "Copy" menu item copies the current selection to the
clipboard.




Equivalent toolbar button:
\includegraphics[scale=0.5]{copy.png}.


\paragraph{Cut}




The "Cut" menu item cuts the current selection to the
clipboard.




Equivalent toolbar button:
\includegraphics[scale=0.5]{cut.png}.


\paragraph{Paste}




The "Paste" menu item pastes the current contents of the
clipboard.




Equivalent toolbar button:
\includegraphics[scale=0.5]{paste.png}.





\paragraph{Tools menu}

\paragraph{New Connection...}





The "New Connection..." menu item closes the current database
connection and brings up the Connection settings dialog (SQLite version, MySQL/PostgreSQL version).




This allows you to connect to a new database, or to reconnect if
the connection was lost, or to use a different configuration file.





Equivalent toolbar button:
None.


\paragraph{Execute query}




The "Execute query" menu item attempts to execute the contents of
the input area as an MQL query
against the backend.  The output
area will show the results.




Equivalent toolbar button:
\includegraphics[scale=0.5]{flash.png}.


\paragraph{Configure...}




This menu-item has not been implemented yet.  Sorry.





\paragraph{Help menu}

\paragraph{About Emdros Query Tool...}




This brings up the "About box".  Press "OK" to dismiss it
again.




Equivalent toolbar button:
None.





\subsubsection{Input area}



The input area is the top left pane:


\includegraphics[scale=0.5]{InputArea.png}



Use it to write/edit your MQL query, or to write/edit a
configuration file.
 

\paragraph{Example}




Here a query has been written in the input area:


\includegraphics[scale=0.5]{InputAreaExampleQuery.png}



\subsubsection{Output area}



The output area is the bottom left pane:


\includegraphics[scale=0.5]{OutputArea.png}

\paragraph{Example}




Here a query has been executed, and the output area shows the
progress of the query.  Of course, the output itself would also be
shown if one scrolled the window.


\includegraphics[scale=0.5]{OutputAreaSampleOutput.png}



\subsubsection{Database Schema area}

\paragraph{What is a schema?}






The "schema" of an Emdros database consists of the enumerations,
object types, and monad sets created as "meta-data" in the
database.




An object type could be, e.g., "Word", "Phrase", "Clause", "Verse",
"Line", etc., and the designer of the database has determined these
when he or she created the Emdros database.




An enumeration is a set of labels that can be used for easy
mnemonic access to commonly used values.  Examples could include
"noun", "verb", "adjective", etc. for the enumeration
"part\_of\_speech".


\paragraph{The schema area}




The pane in the right-hand side shows the database schema of the
current database in a tree.


\includegraphics[scale=0.5]{MainScreen.png}

\paragraph{The schema tree}




The schema area consists of a tree which is fully
expandable/collapsible by pressing the "+" and "-" buttons next to a
label.




The "root" of the tree shows the name and/or location of the
current database.




Underneath the root, there are three categories:


\begin{enumerate}

  
\item {\bf Enumerations}

  
\item {\bf Object types}

  
\item {\bf Monad sets}

\end{enumerate}



These will be deal with in turn.



\paragraph{Enumerations}



An enumeration is a set of labels for easy use of mnemonic
values.




The "Enumerations" top-level category can be expanded to show the
enumerations available in the current database.




For example:


\includegraphics[scale=0.5]{SchemaEnumerations.png}



The {\em enumerations} appear at the level just below the
"Enumerations" label.  That means, in this picture, "boolean",
"book\_name\_t", and "verbal\_stem\_t" are all enumerations.




You can expand or collapse each enumeration to show or hide its
enumeration labels.  In the above picture, "true" and "false" are
labels in the "boolean" set, whereas "NA", "imperative", "perfect",
etc. are labels in the "verbal\_tense\_t" enumeration.



\paragraph{Object types}

\paragraph{Crash course in object types}




An object type groups objects with similar characteristics.  For
example, the database designer may have created the object types
"Word", "Phrase", "Clause", "Book", etc.







An object type has a number of "attributes", also known as
"features".  The features that an object type has determines the values that can be associated with objects of the given type.




For example, an object of type "Phrase" may have values for
features such as "phrase\_type", and "function".  This is up to the
database designer to decide.




A feature always has a type, drawn from the following table:


\begin{itemize}

  
\item integer: A positive or negative integer, or 0.

  
\item string: An 8-bit string

  
\item ascii: A 7-bit string

  
\item id\_d: A pointer that points to the "self" feature of another object.

  
\item {\em everything else}: An enumeration.

\end{itemize}



All objects have a "self" feature which is a unique ID.  Ohter
objects can refer to a given object by the value of that object's
"self" feature.  Database designers use the "id\_d" feature type for
this purpose.


\paragraph{The schema tree}




Here is a partial schema tree showing the object types of a sample
database:


\includegraphics[scale=0.5]{SchemaObjectTypes.png}



The object types appear directly below the "Object Types" label.
For example, in the above picture, "chapter", "book", "verse", and
"word", are all object types.




You can collapse or expand each object type by pressing the "+" and
"-" buttons next to the object type's name.  When expanded, the
{\em features} will appear, along with their type (see the list
above).




If a feature's type is an enumeration, then the feature label can
be expanded to show the enumeration labels.  In the above example, the
object type "chapter" has a feature "book" whose type is the
enumeration "book\_name\_t".  The enumeration labels are not visible,
but the user could clikc the "+" next to "book" to expand the tree and
see the enumeration labels.




The object type "word" has a feature "gender" which is of the
enumeration type "gender\_t".  This has been expanded to reveal the
labels "NA", "masculine", "feminine", and "unknown".




\paragraph{Monad sets}



The user can create "arbitrary, named monad sets" in the database
by using the "CREATE MONAD SET" query.  These can be viewed with the
schema tree:


\includegraphics[scale=0.5]{SchemaMonadSets.png}



The names of the monad sets appear just below the "Monad Sets"
label in the tree.




Each monad set name can be exapanded to reveal the monad set in
question.




It is just coincidence that the above sets are all single-range
sets: The monad sets can be quite arbitrary, and may therefore have
gaps.


\paragraph{Usage}




The main benefit of having arbitrary monad sets is that they can be
used to limit searches, like this:


\begin{verbatim}

SELECT ALL OBJECTS
IN Poetry
WHERE
[Clause]
GO

\end{verbatim}



Here all clauses in the monad set named "Poetry" will be retrieved.



\subsection{Normal usage}