
\section{Repositories Schema}
\label{sec:repSchema}

Figure~\ref{rep-schema} illustrates the ER model of the MDR and STR.

\begin{stdfigure}{Repository Schema}{rep-schema}

\stdpicmag{-3}
\footnotesize

\begin{picture}(66,68)
\entity(30,0){model}
\keyattribute(30,3)(26,4){mid}
\attribute(30,1)(26,0){model}
\relationship(34,4)(34,16){mid}{0:N}{1:1}
\entity(30,16){construct}
\keyattribute(38,19)(42,20){cid}
\attribute(38,17)(42,16){construct}
\relationship(18,18)(30,18){\underline{cid}}{1:1}{0:N}
\entity(10,16){scheme}
\keyattribute(10,20)(6,22){pos}
\attribute(10,19)(6,20){type}
\nullattribute(10,18)(6,18){argMid}
\nullattribute(10,17)(6,16){argCid}
\attribute(10,16)(6,14){HDMType}
\attribute(12,16)(11,12){lower}
\attribute(16,16)(17,12){upper}
\attribute(14,20)(14,24){isKey}
\relationship(34,20)(34,32){cid}{0:N}{1:1}
\entity(30,32){schema\\object}
\keyattribute(31,32)(30,29){obid}
\attribute(31,36)(30,39){value}
\attribute(37,36)(38,39){is\_temp}
\relationship(38,32)(57,32){from\\obj}{0:N}{0:1}
\path(57,32)(57,40)
\relationship(38,36)(51,36){to\\obj}{0:N}{0:1}
\path(51,36)(51,40)
\entity(50,40){transforma\-\\tion}
\attribute(58,43)(62,44){action}
\nullattribute(58,42)(62,42){function}
\nullattribute(58,41)(62,40){cons}
\relationship(38,52)(57,52){from\\schema}{0:N}{1:1}
\path(57,52)(57,44)
\relationship(38,48)(51,48){to\\schema}{0:N}{1:1}
\path(51,48)(51,44)
\relationship(18,34)(30,34){\underline{obid}}{1:1}{0:N}
\entity(10,32){object\\scheme}
\keyattribute(10,35)(6,36){scheme\_pos}
\attribute(10,33)(6,32){sobid}
\relationship(34,36)(34,48){\underline{oid}}{1:1}{0:N}
\entity(30,48){schema}
\isa(27,50)(30,50)
\generalisation(21,49){es}
\path(18,50)(21,50)
\entity(10,48){extensional\\schema}
\isa(14,57)(14,52)
\generalisation(11,57){edb}
\path(14,64)(14,59)
\entity(10,64){extensional\\database}
\isa(21,66)(18,66)
\generalisation(21,65){\shortstack{data\\source}}
\path(27,66)(30,66)
\entity(30,64){data\\source}
\relationship(38,66)(50,66){sid}{0:N}{1:1}
\entity(50,64){access\\method}
\keyattribute(58,68)(62,70){amid}
\attribute(58,67)(62,68){url}
%\attribute(58,66)(62,66){pid}
\attribute(58,65)(62,64){db\_driver}
\attribute(58,64)(62,62){username}
\entity(30,56){protocol}
\keyattribute(30,59)(26,60){pid}
\attribute(30,57)(26,56){name}
\relationship(38,58)(52,58){pid}{0:N}{1:1}
\path(52,58)(52,64)
\end{picture}

\end{stdfigure}
