1. Nguyn ThanhTng
C s d liu RNG BUC TON VN
21/03/2011
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C s d liu

2. Ni dung
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C s d liu
2
Rng buc ton vn
NULL value
Rng buc kha
Rng buc ton vn thc th
Rng buc ton vn tham chiu
Cc tc v cp nht
3. Rngbuctonvn
Rngbuctonvn(integrity constraint)lmt qui tcmttcccdliutrong CSDL phithamn qui tc ny.
C 3 loirngbucchnh:
Rngbuckha (key constraints)
Rngbuctonvnthcth (entity integrity constraints)
Rngbuctonvnthamchiu (referential integrity constraints)
Ngoira
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C s d liu
4. Rngbuctonvn (tt)
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C s d liu
nhnghamintrchoccthuctnh
5. Null value
Biudingitrchomtthuctnhhintikhngbit
Thahipdliuchay hay cbit
Biudinskhngcgitr, nkhcvis 0 hay chuitrng
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C s d liu
6. Rngbuckha (Key constraints)
Siu kha (Superkey) ca R l tp hp cc thuc tnh ca R lm cho 2 dng trong quan h hp l r(R) c siu kha khc nhau.
Kha (Key) ca R l siu kha nh nht. Nu b i bt k thuc tnh no trong kha K th kt qu s khng l siu kha ca R.
Mt quan h c vi kha d tuyn, chn ra mt kha d tuyn l kha chnh. Thuc tnh kha chnh c gch chn.
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C s d liu
7. Rng buc kha (tt)
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V d: Car (License_number, Engine_serial_number, Make, Model, Year) c 2 kha d tuyn:
{License_number} v {Engine_serial_number}
{License_number, Make} l siu kha, khng l kha
8. Rng buc ton vn thc th
Rng buc ton vn thc th (Entity Integrity) cc thuc tnh kha chnh PK ca lc quan h R khng cha gi tr null trong tt c cc dng ca r(R). V cc gi tr ca kha chnh c dng xc nh cc dng.
Cc thuc tnh ca R (thuc tnh kha hay khng kha) cng c th b rng buc khng cho php cha gi tr null.
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C s d liu
9. Rng buc ton vn tham chiu
Rng buc ton vn tham chiu (Referential Integrity) l mt rng buc gia 2 quan h, xc nh quan h gia cc dng trong 2 quan h:
Quan h tham chiu
Quan h b tham chiu
Dng t1 trong quan h tham chiu R1 cha cc thuc tnh kha ngoi FK (foreign key) tham chiu n cc thuc tnh kha chnh PK (ca dng t2) trong quan h c tham chiu R2.
t1[FK] = t2[PK]
Biu din trong lc quan h CSDL bng ng cong hng t R1.FK n R2.
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C s d liu
10. Rng buc ton vn tham chiu (tt)
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11. Rng buc ton vn tham chiu (tt)
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Rng buc ton vn tham chiu l mt qui tc m tt c cc gi tr ca kha ngoi FK trong quan h tham chiu R1 l:
Mt gi tr kha chnh PK tn ti trong quan h c tham chiu R2.
Gi tr NULL
Trong trng hp 2, kha ngoi R1 khng nn l mt phn ca kha chnh ca quan h R1 .
12. Rng buc ton vn tham chiu (tt)
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C s d liu
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13. Cc loi rng buc ton vn khc
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Rng buc ton vn ng ngha:
Da trn ng ngha ca ng dng v khng th c biu din trong m hnh.
V d: S gi lm vic ln nht ca mt nhn vin cho tt c cc d n l 56 gi/tun.
Rng buc tnh (State/Static)
Rng buc ng: v d lng ca nhn vin ch tng
14. Ni dung
21/03/2011
C s d liu
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Rng buc ton vn
NULL value
Rng buc kha
Rng buc ton vn thc th
Rng buc ton vn tham chiu
Cc tc v cp nht
15. Cc tc v cp nht
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Tc v thm (INSERT) dng
Tc v xa (DELETE) dng
Tc v thay i (MODIFY) dng
Cc rng buc ton vn khng c vi phm bi cc tc v cp nht.
16. Cc tc v cp nht (tt)
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Tc v Thm: thm mt dng mi t vo mt quan h R. Khi thm dng mi phi m bo cc rng buc CSDL khng b vi phm.
Gi tr ca mt thuc tnh phi ng kiu (thuc domain ca thuc tnh )
Cc gi tr ca thuc tnh khakhng c NULL
Cc gi tr ca kha phi khc nhau tng i mt
Gi tr ca kha ngoi phi tham chiu n mt dng tn ti trong quan h tng ng hay bng NULL.
17. Cc tc v cp nht (tt)
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C s d liu
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Tc v Xa: loi mt dng tn ti trong quan h R. Khi xa mt dng, cc rng buc sau khng c vi phm:
Dng phi tn ti trong CSDL
Rng buc ton vn tham chiu khng c vi phm
Tc v Thay i: thay i cc gi tr ca cc thuc tnh ca dng tn ti t trong quan h R
18. Cc tc v cp nht (tt)
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Trong trng hp rng buc b vi phm:
Hy tc v gy ra li
Thc thi tc v nhng thng bo cho ngi dng v vi phm.
Thm Trigger vo cp nht, khi vi phm s c sa cha (CASCADE, SET NULL)
Thc thi th tc sa li do ngi dng nh ngha.
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Q&A
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