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FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
EXISTS NOTEXISTS IN NOT IN
SPZ.Sno=SPY.Sno AND SPZ.Pno=SPY.Pno SPZ.Sno=SPX.Sno AND SPZ.Pno=SPX.Pno SPZ.Sno=SPX.Sno AND SPZ.Pno=SPY.Pno SPY.Sno=′168′ AND SPZ.Pno=SPY.Pno
FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
SPY.Sno=’168’ SPY.Sno＜＞’168’ SPY.Sno=SPX.Sno SPY.Sno＜＞SPX.Sno
SPZ.Sno=SPY.Sno AND SPZ.Pno=SPY.Pno SPZ.Sno=SPX.Sno AND SPZ.Pno=SPX.Pno SPZ.Sno=SPX.Sno AND SPZ.Pno=SPY.Pno SPY.Sno＜＞’168’ AND SPZ.Pno=SPY.Pno
S(u)∧SP(v) ∧P(w) SP(u) ∧S(v) ∧P(w) P(u) ∧SP(v) ∧S(w) S(u) ∧P(v) ∧SP(w)
Sno是主键 Pno是主键 三个属性都是主键 Pno和Qty是主键
EXISTS NOT EXISTS IN NOT IN
FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
EXISTS NOT EXISTS IN NOT IN
FOREIGN KEY PRIMARY KEY FOREIGN KEY（Sno） REFERENCES S FOREIGN KEY（Pno） REFERENCES P
SPY.Sno=′168′ SPY.Sno<>′168′ SPY.Sno= SPX.Sno SPY.Sno<>SPX.Sno
SPZ. Sno=SPY. Sno AND SPZ. Pno=SPY. Pno SPZ. Sno=SPX. Sno AND SPZ. Pno=SPX. Pno SPZ. Sno=SPX. Sno AND SPZ. Pno=SPY. Pno SPY. Sno=’168’ AND SPZ. Pno=SPY. Pno
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