R: &
X |
Zl |
Z2 |
xl |
zl |
zr |
xl |
z2 |
zl’ |
x2 |
zl |
z2’ |
Zl |
Z2 |
Y |
zl |
zr |
yi |
zl |
zl’ |
y2 |
zl |
z2’ |
y3 |
z2 |
iT |
y4 |
R IxIro 5:
X |
Z1 |
Z2 |
Y |
xl |
zł |
zr |
yi |
X l |
zl |
zl’ |
y2 |
x2 |
zl |
zT |
y3 |
NULL |
z2 |
zT |
__ |
Bazy danych. Wykład 5 18