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Databases Queries in relational algebra

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Databases Queries in relational algebra

Tania Cerquitelli

©2014 Politecnico di Torino 1

D B M G

Ottimizzatore

Esercizi Esercizi

Tania

Tania Cerquitelli Cerquitelli

D B M G

Esercizio 3 - Seminari

Sono date le relazioni seguenti (le chiavi primarie sono sottolineate):

o SEMINARIO (IdS, Titolo, Max#Partecipanti, Argomento)

o PARTECIPANTE (CodFiscP, Nome, Cognome, Società, Ruolo, Data Nascita)

o REGISTRAZIONE (CodFiscP, Data, IdS, Città)

2

(2)

Databases Queries in relational algebra

Tania Cerquitelli

©2014 Politecnico di Torino 2

D B M G

Statistiche

o card(SEMINARIO) ≈ 10

3

tuple o Valori distinti di argomento 100 o card(PARTECIPANTE) ≈ 10

5

tuple

o Valori distinti di ruolo 20

o card(REGISTRAZIONE) ≈ 10

8

tuple o Valori distinti di città 100

o MIN (Data)=1-1-2013 o MAX (Data)=31-12-2013

3

D B M G

Query 1

SELECT P.Nome, P.Cognome FROM PARTECIPANTE P

WHERE (P.Ruolo = ‘Manager’ or P.Ruolo = ‘Direttore’ ) and P.CodFiscP NOT IN (SELECT CodFiscP

FROM REGISTRAZIONE R. SEMINARIO S WHERE R.IdS=S.IdS and

Argomento=‘Ingegneria civile’)

4

Riferimenti

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