Chapter 6 Relational Algebra and the Relational Calculus
7
0
0
Full text
(2)
(3)
(4) c pp p.
(5) . p. p. p. p. p. p. p. p. p. p. p. p. p. p. pp
(6) . p. p. p. p. p. p. p. p. p. p. p. p. p. p. pp
(7) . p. p. p. p. p. p. p. p. p. p. p. p. p. p. ppp
(8) p p p p p!"#pFundamentals of Database Systems, 5th edition,p$% &'(#p )pp***)*&+,),% - pp c
(9)
(10) pp. pp. )p )p )p. )p )p
(11) )p )p. º (p% p%% .p / 0p p123 0p % p+p%% p4% pp%(p 5 (p% p%% .p326!p p768662!p $% p% p%% p 9 p%4p:p p% p+p 0p% p,,p 7% p% p,,p (p "*p:% p 9,p ,p++%(p. [
(12) p p p p. % % p4%p%% p% p% p %p 5p4%p p p% p:p p75;p º p%*p % pp%p%p*% p. p
(13) pp p%p+p4% -%,p </pp"p4% p% p+p p,,p !20p ,p p%p+,pp(pp p. $+p.
(14) p. 2% pp. p p% p;%p*p+%p p% -+#p+#p % #p,% p p
(15) pp+%p
(16) pp(p%p%p pp=pp</pp+%p p % p. . . ! "
(17) . #
(18)
(19) 2p% p
(20)
(21) p #p+p. $ c !20p ,p%p</p / 0p p
(22)
(23)
(24)
(25) p !%% .p % &%
(26)
(27)
(28) & p p&p% p+p9% p*%pppp% p 9 .p p p. % p p%4p %p / 0p%% p. %
(29)
(30)
(31) &p&p! +p%4p,.p >+p ?p>,% % p%?p>,% p"?p %p >+p ?p>,% % p%?p>+p ?p %
(32) &p&p$+p4% pVp %
(33) &p&p2 p%4p@A#p>#p>A#p?#p?A#pBACp.
(34) %
(35)
(36) " &p&p % p"p4% pp+p% p ,% p,% % p,p,% ,p+(p$!7#p2#p!20p $,% p%4p / 0.p $(p>,% p,% % ?p (p%p,pptp pVp + p+pp p 64p0º #pptpp,p p !%p%"% p4%p,%% p+p p. / 0pp (p&pp%p% p% p 2% ppp%p,pp "(p. '()* c / 0p,p% p%*p4% pp% p*p, p%p ()* c
(37) +
(38) p !%% .p % &% & p p&p% p+p9% p*%pppp% p % &p&p7p+p4% pp% pVp $,% p%4p123 0.p p p p p. % p,% p+p4% p>+p?p % p,pptp pVp 6 pp%pp p>+p?p %"p,pp. )4)#p ,p%D,% p. ,-
(39)
(40) >?> ?Vp %pp p>&p> ?Vp.
(41) >? p. , . / !%% .p % &j. '
(42) 0. 0p&p p% pVp%pSp p+p$p%p5p. % &j 0p&p p% pVp%pSpp % &. '
(43) 0. 0p&p p+p$p%p5p. ')
(44) % pVp pSp p+p
(45)
(46) .p p p. p +p%4p+p ,p,%% pp%4p+pp p% p. pp
(47) ) p. '#.[). %&j 6 ,ppppp ppVp pSp 7,ppp %"p. '[. c[). %&j 6 ,ppppp p+%pVp
(48) pSp. ' 1[ .c /[.#0 2j 6 ,pppppVp+p
(49) p pSp pp º!62!p p6!0 062!pp,% "p p%,"p 0p76 ! pp %p,% "p. ''c [ .()1#cc)()1#c0 j $,% .p.
(50) p p p p. !*p% p % + p"(pp4% pVp*p"(pp4% pSp ! +p%4ppAp! +p%4pp pVp9p +p%4pp pSp $+pApp$+p%4pV#p$+p%4pSpp. pp
(51) ) p 24 p,p+(p / 0p -%p123 0p. ,
(52)
(53)
(54) ,*)[. % + ppp4% p*%p% p %pp p% p 7 %p+(p>?p !%% p 3%22 % &%
(55)
(56)
(57) &jp % pV$#p$#p)))#p$ p pS5#p5#p)))#p5 p pQ$#p$#p)))#p$ #p5#p5#p)))#p5 pp% pp4%p,p,% + % p%4p#p% p4% p p p% p4% p#p* "pp,% + % p4p>D% p,% % ?p %
(58)
(59)
(60) &p&p>,% % ?p$!7p>,% % ?p$!7p)))p$!7p>,% % ?p *p>,% % ?pp$p>0E 0$?p5D#p+p%4pVp pS,p)#p*p p% p 24 #p% p+ppp (p (p pp%ppp4% p (p,%% p%pp 326!pp. p%p 2p127º 0p&p,% + % p%4pp4% pVp pSp 326!pp
(61) p%p 2p127º 0p&p,% + % p4p>D% p,% % ?p 326!pp:" p%p / 0pp 2p127º 0pp. ,' 3#[*)[. >D% p,% % ?p "%"p% (pAp 1p%4p+pp:p. ,'. # $*)[..
(62) >D% p,% % ?p "%"p% (pAp pp% (p% p%4pp:pp. ,,c
(63) p@> ?#p>?#p>,?#p&#p9Cppp,% pp%4p% p+p%% )p / 0#p123 0#pº!62!#p;6!º#p p 2p127º 0p, p p$!Fp%p % p+p%% p Vp>%% ?pSp 6!0 0 062!.pVp>,?SpApVp>,?pSp&pVp&pSp>,?pSp&pVp 326!.pVp>?>,% % ?ppAp> ?>,% % ?Vp9pSp. ,4.
(64) - 9 .pp
(65) )p G,p %% p%p p,% %% p%4p% p%% p p%p,% % pp 0pp,p,%% p%p% p+p9% p /4p %pp p% p%pp:(p 2% pp p %p %%ppp º4p%p,% p% % - p
(66) ) p2p%% p
(67) ) p 9 p pp. ! c 5
(68) 11
(69) 2
(70) 2
(71) /
(72) pp p.
(73) . p. p. p. p. p. p. p. p. p. p. p. p. p. p.
(74) pp
(75) . p. p. p. p. p. p. p. p. p. p. p. p. p. pp
(76) . p. p. p. p. p. p. p. p. p. p. p. p. p. p. p. p. p.
(77)
Related documents
• Queries in relational algebra are applied to relation instances, result of a query is again a relation instance. • Six basic operators in
Theorem: Each of the five basic relational algebra operations is independent of the other four, that is, it cannot be expressed by a relational algebra expression that involves
The right to terminate a contract for breach of condition is modified in relation to non-consumer contracts for the sale of goods by the Sale and Supply of Goods Act 1994, s 4(1),
The abstract presented the results of the ANRS IPERGAY trial demonstrating the high effectiveness (86% relative reduction of HIV incidence with TDF/ FTC vs. placebo) and
One says that a query language is relationally complete if it can express all queries that can be expressed in tuple calculus or relational algebra.. SQL is a relationally
◦ Keeps all tuples in both the left and the right relations when no matching tuples are found, padding them with null values as needed.. Left
- [F-Expl] showed that long-span curvature increased with increase of Die #3 position, or the increase of the intensity of straightening under the conditions of this study.
As the inclusion of gravity can drastically change the phase diagram of matter fields, the inclusion of matter degrees of freedom in a gravitational theory can strongly affect the
