BD - REPÀS: àlgebra

-- 1)

A = EMPLEATS(NUM_EMPL = 3)
B = A[SOU]
C = B{SOU->SOU1}
D = EMPLEATS[SOU > SOU1]C
R = D[NOM_EMPL]

-- 2) (Falla un privat)

A = PROFESSORS(SOU > 2500)
B = DESPATXOS(SUPERFICIE < 20)
C = B[MODUL, NUMERO]
D = C{MODUL->MO, NUMERO->NU}
E = ASSIGNACIONS[MODUL=MO, NUMERO=NU]D
F = E[DNI, MODUL, NUMERO, INSTANTINICI,INSTANTFI]
G = ASSIGNACIONS - F
H = G[DNI]
I = H{DNI->DN}
J = PROFESSORS[DNI=DN]I
K = J[DNI, NOMPROF, TELEFON, SOU]
L = K_u_A
M = L[NOMPROF]

-- 3)

A = professors(sou != 100000)
B = assignacions*A
C = B[modul, numero]
D = assignacions[modul, numero]
E = D-C
F = E*assignacions
G = F[dni, modul, numero, instantinici]

-- 4)

A = EMPLEATS(NUM_EMPL = 2)
B = A[NUM_DPT]
C = B*DEPARTAMENTS
D = C[NOM_DPT]
E = A[NUM_PROJ]
F = E*PROJECTES
G = F[NOM_PROJ]
H = D*G

-- 5)

A = EMPLEATS[NUM_DPT, CIUTAT_EMPL]
B = A{NUM_DPT->ND, CIUTAT_EMPL->CE}
C = EMPLEATS[NUM_DPT=ND, CIUTAT_EMPL!=CE]B
D = C*DEPARTAMENTS
E = D[NUM_DPT, NOM_DPT]

-- 6)

A = EMPLEATS(CIUTAT_EMPL!='MADRID')
B = EMPLEATS[NUM_DPT]
C = A[NUM_DPT]
D = B-C
E = D{NUM_DPT->ND}
F = DEPARTAMENTS[NUM_DPT=ND]E
G = F[NUM_DPT, NOM_DPT]

-- 7)

A = EMPLEATS(SOU > 200000)
B = A[NUM_DPT]
C = B{NUM_DPT->ND}
D = DEPARTAMENTS(CIUTAT_DPT='MADRID')
E = D[NUM_DPT=ND]C
F = E[NUM_DPT, NOM_DPT]

-- 8)

A = PROJECTES{NUM_PROJ->NP}
B = EMPLEATS[NUM_PROJ]
C = A[NP = NUM_PROJ]B
D = C[NUM_PROJ, NOM_PROJ, PRODUCTE, PRESSUPOST]
E = PROJECTES-D
F = E[NOM_PROJ, NUM_PROJ]

-- 9)

A = EMPLEATS{NUM_DPT->ND}
B = A[ND=NUM_DPT, CIUTAT_EMPL=CIUTAT_DPT]DEPARTAMENTS
C = B[NOM_EMPL, NUM_EMPL]

-- JosepRivaille