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GDB-4: Aufgabe 4 korrigiert.

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Jim Martens
2013-12-12 15:34:07 +01:00
parent 9913b6fc95
commit 3b2a28a11d
1 changed files with 10 additions and 8 deletions
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18
gdb/G62B4_Dittrich-Lindemann-Martens.tex
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@ -173,14 +173,16 @@
anfänglicher Operatorbaum:\\ anfänglicher Operatorbaum:\\
\begin{tikzpicture}[shorten >=1pt,node distance=1.1cm,on grid] \begin{tikzpicture}[shorten >=1pt,node distance=1.1cm,on grid]
\node (proj) {$\pi_{Person.PNR, Person.Vorname, Person.Nachname}$}; \node (proj) {$\pi_{Person.PNR, Person.Vorname, Person.Nachname}$};
\node (sel) [below=2.0 of proj] {$\sigma_{Obst.Sorte\text{ LIKE 'K\%'}}$}; \node (sel) [below=2.0 of proj] {$\sigma_{Obst.Sorte\text{ LIKE 'K\%'}}$};
\node (join) [below=2.0 of sel] {$\underset{Person.Lieblingsobst = Obst.ONR}{\bowtie}$}; \node (sel2) [below=2.0 of sel] {$\sigma_{Obst.ONR=Person.Lieblingsobst}$};
\node (person) [below left=2.0 and 2.0 of join] {Person}; \node (catProd) [below=2.0 of sel2] {x};
\node (obst) [below right=2.0 and 2.0 of join] {Obst}; \node (person) [below left=2.0 and 2.0 of catProd] {Person};
\node (obst) [below right=2.0 and 2.0 of catProd] {Obst};
\path (proj) edge node [right] {400} (sel) \path (proj) edge node [right] {400} (sel)
(sel) edge node [right] {2000} (join) (sel) edge node [right] {2000} (sel2)
(join) edge node [left] {2000} (person) (sel2) edge node [right] {50000} (catProd)
(join) edge node [right] {25} (obst); (catProd) edge node [left] {2000} (person)
(catProd) edge node [right] {25} (obst);
\end{tikzpicture} \end{tikzpicture}
optimierter Operatorbaum:\\ optimierter Operatorbaum:\\
@ -196,5 +198,5 @@
(sel) edge node [right] {25} (obst); (sel) edge node [right] {25} (obst);
\end{tikzpicture} \end{tikzpicture}
Der zweite Operatorbaum ist klar performanter, da die Selektion der Obstsorte bereits vor dem Join stattfindet. Der zweite Operatorbaum ist klar performanter, da die Selektion der Obstsorte bereits vor dem Join stattfindet und das kartesische Produkt und die zweite Selektion zu einem Join verbunden wurde.
\end{document} \end{document}