This document provides information on relational database concepts prepared by B. Christopaul (MSc, BSc). It discusses key aspects of relational databases including tables, rows, fields, data types, relationships, integrity constraints, and standards. Relational databases store data in tables with rows and columns and allow defining relationships between tables. This helps reduce data redundancy and inconsistencies. The document also touches upon database security, data integrity and issues in multi-user environments.

1. juTj;jsk;
Prepared BY
B.Christopaul (MSc, BSc)

2. juTData
• msTfs;>vOj;JUf;fs;> FwpaPLfs;vd;gtw;iwf; nfhz;Lfzpdpahy;
Nkw;nfhs;sg;gLk;nray;Kiwfs;> ,it kpd;rkpQ;irfshfflj;jg;gl;Lfhe;j
xspapay;> nghwpapay; Clfq;fspy; Nrkpj;Jitj;jyhFk;.
2B.Christopaul (MSc, BSc)

3. jfty;: Information
• jfty; vd;gJ mjid ngw;Wf;nfhs;gtWf;Ftpsf;fj;ijf;nfhLf;ff;$ba
tifapy; Kiwtopg;gLj;jYf;fl;gLj;jg;gl;ljuthFk;.
3B.Christopaul (MSc, BSc)

4. gpuNahfnray;Kiwfs;
• Njitfisf;fz;lwpjy;
• ERtiuglj;ijjahupj;jy;
• ERtiuglj;ijnjhlu;GKiwjuTj;jsml;ltizf;Fkhw;Wjy;
• ,ay;ghf;fy;
• xUikg;ghLfl;Lg;ghbly;
• DDL cgNahfpj;Jnjhlu;GKiw juTj;jsk;cUthf;fy;
• DMLcgNahfpj;JjuT Kfhikj;Jtk;nra;jy;
4B.Christopaul (MSc, BSc)

5. njhlu;Gepiyj;juTj;jsk;
• ,Utplaq;fs;G+u;j;jpahf;fg;glNtz;Lk;.
– rfy juTfSk;ml;ltizfspy;khj;jpuk;Nrkpj;jy;
– rfy nraw;ghLfs;(operations)%yKk;gioaml;ltizfs;ghtpf;fg;gl;LGjpa
ml;ltizfs;cUthFjy;.
• vdNt>SQLfl;lisfs;%yk;fpilf;Fk;midj;JngWNgWfSk;ml;ltizfshFk;.
5B.Christopaul (MSc, BSc)

6. njhlu;Gepiyj;juTj;jsk;(Relational Database)
• ,t;tpsf;fj;jpw;fikajuTj;jsKfhikj;JtKiwiknahd;iwg;(DBMS)
gad;gLj;jpml;ltizfs;gytw;iwcUthf;Ftjhy;khj;jpuk;mJxUjuTj;js
Kfhikj;JtKiwik(Relational Database)nahd;whfmiktjpy;iy
vd;gJftdpf;fg;glNtz;batplakhFk;.
• cUthf;fg;gl;lml;ltizfSf;fpilapy;njhlu;GKiwcUthf;ff;$bathW
ml;ltizfs;cUthf;fg;glNtz;Lk;.
6B.Christopaul (MSc, BSc)

7. njhlu;Gepiyj;juTj;jsk;(Relational Database)
• xd;Wld;xd;Wnjhlu;GilaJk;>xOq;fikf;fg;gl;lJkhdjuTj;jsnkhd;wpd;
njhFg;Gvd vspjhf tpsf;fKbAk;.
• ,jd;%d;WgFjpfis,dq;fhzKbAk;.
– ml;ltiz(Table)
– gjpT/tupir(Record/Row/Tuple)
– Gyk;(Field/ Attribute)
7B.Christopaul (MSc, BSc)

8. Gyq;fs;
• njhlu;Gepiyj; juTj;jsnkhd;wpy; juTfs; gjpag;gLtJ Gyq;fspyhFk;.
• Gynkhd;wpDy; xNutifahd juTfs; gjpag;gLk;.
• njhlu;Gepiyj; juTj;jsnkhd;wpy; Gynkhd;W NkYk; gpupglhJ
• mjhtJ NkYk; rpW gFjpfshf NtWgLj;Jtjw;J juTj;jsj;jpw;F KbahJ.
• cjhuzk;:
– jpfjp(date) Gynkhd;nwdpd;mjidtUlk;>khjk;>jpfjp vdnjhlu;Gepiyj;juTj;jsnkhd;wpw;F
KbahJ.mt;thWNjitnadpd;nkdnghUspDs;nra;ag;glNtz;Lk;.
– mJ jpfjpjhd;vd mwpanjhlu;Gepiyj; juTj;jsnkhd;wpw;FKbahJ.
8B.Christopaul (MSc, BSc)

9. Gyq;fs;
9B.Christopaul (MSc, BSc)

10. gjpT
gjpT xd;W Gyk;xd;wpdhNyh gytw;whNyh,Uf;fyhk;
10B.Christopaul (MSc, BSc)

11. ml;ltiz
• ml;ltiznahd;wpy;gjpTfs;
– G+r;rpakhf ,Uf;fyhk;
– Xd;whf ,Uf;fyhk;
– Xd;wpw;;F Nkw;gl;ljhf ,Uf;fyhk;
11B.Christopaul (MSc, BSc)

12. ml;ltiznahd;wpd; ,ay;Gfs;
gjpTfspd; gpujpfs; ,Uf;f KbahJ
gjpTfs; tupir Kiwapy; fhzg;glhJ
Gyq;fs; tupir Kiwapy; fhzg;glhJ
Gyq;fspy; Nrkpf;fg;gl;l ngUkhdq;fs; gpupgl KbahJ. (atomic).
12B.Christopaul (MSc, BSc)

13. • (redundancy) juT kpifikiaf; Fiwj;Jf; nfhs;syhk;
– kpifikapd;fhuzkhf,lf;nfhs;ssTtPzhf;fg;gLfpd;wJ.
– kpifikapidKOikahfePf;fKbAk;vdNth
– my;yJKOikahfePf;fg;gl Ntz;Lk;vd;gJ fUj;jhFk;.
• (inconsistency) xUq;fpirtpd;ikiajtpu;Jf; nfhs;sf; $baik
– ml;ltiznahd;wpd;Kjd;ikr;rhtpNtnwhUml;ltizapy;me;epar;rhtpahfghtpf;fg;gLkplj;JxNujuT
kPz;Lk;kPz;Lk;gjpTnra;ag;gLfpd;wJ.,Jjtpu;f;fKbahjjhFk;.,q;F kpifikgw;wparpf;fy;
Njhd;Wfpd;wJ.
– mt;thwhdkPs;gjpTfs;eilngwhtpbd;ml;ltiz,uz;bw;fpilapyhdnjhlu;GKiw Vw;glhJ.
juTKiwapdhy;fpilf;Fk;ed;ikfs;
13B.Christopaul (MSc, BSc)

14. juTKiwapdhy;fpilf;Fk;ed;ikfs;
• (share) juitg; gfpu;e;Jgad;gLj;jf; $baik
– juTj;jsnkhd;wpy;‘juT’vd;gJ mq;F Nrkpf;fg;gl;bUf;Fk;ngWkhdq;fs; MFk;.
– mt;thW Nrkpf;fg;gl;bUf;Fk;ngWkhdq;fs; %yk;gadu; xUtuhy;tpsf;fnkhd;iw ngwKbAkhapd; mJjftyhFk;
– gadu;fs; ,Utifg;gLtu;
• jdpg;gadu; (single user)
– rhjhuzkhfxUfzpdpiag;ghtpg;ghu;
– xU fzpdpAs;xd;Wf;FNkw;gl;lgpuNahfq;fs;(applications) %yk;xNu juTgad;gLj;jKbAk;
• gw;;gadu;(multi user)
– rhjhuzkhfxd;Wf;FNkw;wl;lfzpdpghtpf;fg;gLk;
– Xd;Wf;FNkw;gl;lfzpdpfs;ghtpf;fg;gLtjd;%yk;gygadu;fs;xNugpuNahfj;ijxNu rkaj;jpy;Nkw;nfhs;syhk
– ,t;tpU re;ju;g;gq;fspd; NghJk;juT gfpu;T eilngWfpd;wJ.
– xNujilitapy;cUthf;fg;gl;l juitg; gad;gLj;jp Gjpa gpuNahfq;fis cUthf;fyhk;
– ,r;re;ju;g;gj;jpy;gpuNahfnkd;nghUs;fs;juit gfpu;e;J gad;gLj;Jfpd;wd.
14B.Christopaul (MSc, BSc)

15. • (standards) epakq;fis mKy;gLj;jf;$baik
– gpuNahfq;fs; (application)
– juT gpujpepjpj;Jtk; (data representation)
– juT gupkhw;wk; (data exchange)
– juT ngauply; (data naming)
– Mtzg;gLj;jy; (documentation)
juT Kiwapdhy;fpilf;Fk;ed;ikfs;
15B.Christopaul (MSc, BSc)

16. • ghJfhg;G tiuaiwfis gad;gLj;jf;$baik (security)
– mDfy; topfisf; fl;Lg;gLj;jy;
– gy;NtWgl;l gadu;fSf;F (retrieve, modify, update, delete, etc)
cupkkspj;jy;.
– ,yj;jpuzpay; juTj;jsnkhd;wpy; fl;lhak; ,Uf;f Ntz;ba xUmk;rkhFk;
• juT xOq;fikitg;ghJfhj;jy; (integrity)
– kPs;gjpT Vw;gLjypd; tpiythy; cz;lhtjhFk;
– Rupepiy cWjpg;gLj;jy; ,jd; %yk; eilngWk;
– kPs;gjpT ,y;yhtpbDk; rupepiycWjpg;gLj;jy; Ntz;Lk;.
juT Kiwapdhy;fpilf;Fk;ed;ikfs;
16B.Christopaul (MSc, BSc)

17. Njitfismwpe;Jnfhs;sy;
• ghlrhiy xd;wpYs;s khztu;fs; gy;NtW tpisahl;Lf;fspy; <LgLtJld; xt;nthU tpisahl;bw;Fk;
nghWg;ghdxU MrpupaUk; xU ,lKk; ,Uf;Fk;. ,t;tpisahl;Lf;fspy; gq;F nfhs;Sk; khztu;fsJ
Nru;tpyf;fk;> khztu; ngau;> tPl;L Kftup> tFg;G> gq;Fgw;Wk; tpisahl;L> tpisahl;Lj; jiytd;
Nghd;wit mlq;fpa Nfhg;nghd;iw eilKiwg; gLj;Jtjw;F mjpgu; jpl;lkpl;Ls;shu;. xU khztu;
xd;Wf;F Nkw;gl;l tpisahl;Lf;fspy; <Lgl KbAk;. Fwpg;gpl;l xU tpisahl;bw;F xd;Wf;F Nkw;gl;l
khztu;fs; ,Uf;fyhk;. xt;nthU khztDk;; Kd;dNu xU tpisahl;bw;fhf xJf;fg;gl;l kzpj;jpahyq;fspd;
gb fye;J nfhs;sKbAk;.
17B.Christopaul (MSc, BSc)

18. ERtiuglj;ij jahupj;jy
• ,dq;fhzg;gl;lnghJg; ngau;r; nrhw;fisAk;> tpidr; nrhw;fisAk; Ntwhf;fpf;
nfhs;sy;.
• nghJg; ngau;r; nrhw;fs;> cUnghUs;> gz;Gfs; vd;gtw;iwNtwhf;fpf; nfhs;sy;.
• nghJg; ngau;fs;fisAk; (cUnghUs;fs;)> tpidr;nrhw;fisAk; (njhlu;GKiw)
njhlu;GgLj;jy;
• nghJg; ngau;fis(gz;Gfs;)> cUnghUs;fSld; mDtjpj;jy;(Secondment)
• vz;zstpidmwpe;Jnfhs;sy;
18B.Christopaul (MSc, BSc)

19. ER tiuglj;ijnjhlu;GKiwjuTj;jsml;ltizf;F khw;Wjy;
njhlu;GKiw nray;Kiw
Xd;W -xd;W cUnghUs;fs; ,uz;il ml;ltizfs; ,uz;lhfkhw;WjYk;>xUcUnghUspd;Kjd;ikr;rhtpia mLj;j cUnghUspy;
me;epar; rhtpahf mikj;jYk;
Xd;W-gy ,uz;lhfkhw;WjYk;>1:M ,d; 1 w;Fupa gf;fj;jpYs;s cUnghUspd;Kjd;ikr;rhtpia Mgf;fj;jpYs;s
cUnghUspd;me;epar;rhtpahf ghtpj;jYk
gy–gy ,uz;lhfkhw;WjYk;>Gjpjhf ml;ltiznahd;iw cUthf;fpmit ,uz;bdJk;Kjd;ikr;rhtpfisAk; ,izj;JcUthf;fg;gl;l
me;epar;rhtp Gjpa ml;ltizapy; Kjd;ikr;rhtpahf gad;gLj;jy;
19B.Christopaul (MSc, BSc)

20. xd;W-xd;W(1:1) njhlu;Gepiyiafl;bnaOg;gy;
njhlu;nghd;W,y;iy
njhlu;nghd;WcUthf;FtJvt;thW?
xUkhztUf;FxU NkirxJf;fg;gl;Ls;sJ
xUNkirxUkhztUf;FxJf;fg;gl;Ls;sJ
20B.Christopaul (MSc, BSc)

21. xd;W-xd;W(1:1) njhlu;Gepiyiafl;bnaOg;gy;
21B.Christopaul (MSc, BSc)

22. xd;W -gy njhlu;Gepiyia
• ghlrhiy Kiwiknahd;wpy;
– xUkhztUf;F tFg;gpy; khj;jpuk; ,Uf;fyhk;
– xUtFg;gpy; khztu; xUtu; my;yJ gyu; ,Uf;fyhk;.
•xU tFg;gpy; khztu;xUtu;khj;jpuk;;,Uf;fyhk;.
•xU khztUf;Fxd;wpw;F Nkw;gl;l tFg;Gfspy; ,Uf;fyhk;
•ghlrhiyKiwiknahd;iwf; fUJk;NghJ,Jrupahdjy;y.
•vdpDk; jdpahu; tFg;G Kiwikfspy; ,t;thwhd re;ju;g;gq;fs; ,Uf;fyhk;.
22B.Christopaul (MSc, BSc)

23. xd;W -gy njhlu;Gepiyia
,JxU jPu;thf mikahjJVd; 23B.Christopaul (MSc, BSc)

24. xd;W- gy njhlu;Gepiyiafl;bnaOg;gy;
24B.Christopaul (MSc, BSc)

25. gy-gy njhlu;Gepiy
ghlrhiy Kiwiknahd;wpy
• xU khztUf;Fxd;wpw;F Nkw;gl;ltpisahl;Lfspy; gq;F nfhs;syhk;
• xW tpisahl;bw;Fgy khztu;fs;gq;F nfhs;syhk;
25B.Christopaul (MSc, BSc)

26. gy-gy njhlu;Gepiy
,JxU jPu;thf mikahjJVd;
,JxU jPu;thf mikahjJVd;
26B.Christopaul (MSc, BSc)

27. gy-gy njhlu;Gepiy fl;bnaOg;gy;
Gjpjhf ml;ltiznahd;W cUthf;f Ntz;Lk;;
27B.Christopaul (MSc, BSc)

28. gapw;rp - 01
28B.Christopaul (MSc, BSc)

29. gapw;rp - 02
29B.Christopaul (MSc, BSc)

30. gapw;rp - 03
30B.Christopaul (MSc, BSc)

31. gapw;rp - 04
31B.Christopaul (MSc, BSc)

32. gapw;rp - 05
32B.Christopaul (MSc, BSc)

33. ,ay;ghf;Fjy;
• Kjy; ,ay;G
– xNukhjpupahdGyq;fs;(Fields)kPz;Lk;kPz;Lk;cNahfg;gLj;jy;
jtpu;f;fg;gly;.
• ,uz;lhk;,ay;G
– juT(Data)kPz;Lk;kPz;Lk;cNahfg;gLj;jy;jtpu;f;fg;gly;.
• %d;wlhk;
– ml;ltiznahd;wpy;,Uf;Fk;gjpTfs;Kjd;ikr;rhtpapy;khj;jpuk;jq;fpapUg;gij
cWjpnra;jy;
33B.Christopaul (MSc, BSc)

34. Kjy; ,ay;ghf;fy;
• xNukhjpupahdGyq;fs;(Fields) kPz;Lk;kPz;Lk;cNahfg;gLj;jy;jtpu;f;fg;gly;.
• Xd;Nwhnlhd;Wnjhlu;GilaGyq;fisf;nfhz;LjdpnahUml;ltizcUthf;Fjy;.
• Xd;Nwhnlhd;Wnjhlu;Gila Gyq;fisKjd;ikr;rhtp%yk;milahsk;fhzKbAk;vd;gijcWjpr;nra;jy;
• xNutifahdjuTfisgjptjw;Fgy Gyq;fisghtpj;jy;$lhJ.
– cjhuzkhf> ,Utsq;fspypUe;J nghUl;gjpNtl;bw;F tuf; $ba tplankhd;iw NjLk; NghJ Vendor Code 1, Vendor Code 2. vDk;
Gyq;fs; fhzg;glyhk;.
• %d;whtJNru;f;fNtz;bVw;gbd;vd;d elf;Fk;.NkYk;xUGyj;ij Nru;g;gJjPu;ty;y.,jw;F epuyplYk;ml;ltizfis
GJg;gpj;jYk; mtrpakhtJld;>Vendoru;fs;khWk;vz;zpf;iff;F,lkspf;fKbahJ.
• vdNt>rfytpahghupfisAk;cs;slf;ff;$batifapy;‘vendor’vDk;jdpahdml;ltiznahd;wpy;mj;jfty;fisgjpa
Ntz;Lk;.gpwFmjid nghUs;gjpNtl;Lld;Kjd;ikr;;rhtpg;Gynkhd;Wld;njhlu;G gLj;jTk;.
– cjhuzk; item number key, vendor code key.
34B.Christopaul (MSc, BSc)

35. Kjy; ,ay;ghf;fy;
35B.Christopaul (MSc, BSc)
Fwpg;G:
ER tiuglk;rupahf cUthf;fg;gl;lhy;,e;epiy fhzg;glhJ

36. 36B.Christopaul (MSc, BSc)

37. ,uz;lhk; ,ay;ghf;fy;
• rhtpapy; jq;fpapuhj Gyq;fs; ePf;fg;gLfpd;wd.
• gjpTfs; ml;ltizap;d; Kjd;ikr;rhtpapyd;wp NtWtplaq;fspy; jq;fpapUf;ff;$lhJ. (Njitg;gbd;
fyg;Gr;rhtp)
• cjhuzj;jpw;F fzf;fPl;L Kiwiknahd;wpy; thbf;ifahsupd; Kftupiaf; fUj;jpw;nfhs;f.
customerml;ltiznahd;wpw;F Kftup mtrpakhtJ Nghy; Orders, Shipping, Invoices,
Accounts Receivable, CollectionsMfpatw;wpw;Fk; Njitg;gLfpd;wJ.
• thbf;ifahsupd; (customer) Kftupia xt;nthU ml;ltizapYk;; jdpj;jdpahf gjpT nra;tjw;Fg;
gjpyhf customer ml;ltizapy; my;yJ addressml;ltizapy; jdpahfgjpayhk;
37B.Christopaul (MSc, BSc)

38. 38B.Christopaul (MSc, BSc)

39. %d;whk;; ,ay;ghf;fy;
• cjhuzj;jpw;F
• Ckpau; Ml;Nru;gG (Employee Recruitment ) ml;ltizapy;> xUNju;T ehLdu;
(candidate) gy;fiyf;fofg; ngau; kw;Wk; Kftup cs;slf;fg;gl;bUf;ff;$Lk;. Mdhy; FO mQ;ry;
Kiwapy; jfty; mDg;g>rfy gy;fiyf;fyfq;fspd; ngau;g;gl;bay; Njitg;gLk;. gy;fiyf;fyfq;fspd;
tpguq;fs; ‘candidate’ml;ltizapy; Nrkpf;fg;gl;bUg;gpd; Nju;TehLdu;fs; ,y;yhj gy;fiyf;foq;fis
gl;bay;gLj;j Kbahj epiyNaw;gLk;. MfNt gy;fiyf;fofj;jpw;nfd gpwpnjhU ml;ltizia cUthf;fp mjid
‘candidate’ml;ltizAld; rhtpg;Gynkhd;Wld; njhlu;GgLj;jTk;. (university code key)
39B.Christopaul (MSc, BSc)

40. 40B.Christopaul (MSc, BSc)

41. 41B.Christopaul (MSc, BSc)

42. gapw;rp - 01
gapw;rp - 02
42B.Christopaul (MSc, BSc)

43. gapw;rp - 03
43B.Christopaul (MSc, BSc)

44. gapw;rp - 04
44B.Christopaul (MSc, BSc)

45. gapw;rp - 05
Student-
No
Student-
Name
Course-
Code
Course-
Length
(yrs)
Unit-
Code
Unit-Name Lecturer
001 Smith A203 3 U45 Databases II Brown
001 Smith A203 4 U87
Programmi
ng
Scott
003 Soap A104 4 U86 Algorithms Jane
003 Soap A104 4 U45 Databases II Brown
003 Soap A104 4 U25 Business I Red
007 Who A203 3 U12 Business II Pink
007 Who A203 3 U46 Databases I Peter
010 Lemon A323 2 U12 Business II Pink
010 Lemon A323 2 U86 Algorithms Henry
45B.Christopaul (MSc, BSc)

46. Types of constrain
tsfl;Lj;jpl;l tiffs;
• ntw;WkWg;Gf;fl;Lg;ghL(A NOT NULL constrain)
• jdpj;Jtfl;Lg;ghL(A unique constraint)
• Kjd;ikr;rhtpf;fl;Lg;ghL(A primary key constraint)
• me;epar;rhtpf;fl;Lg;ghL(A foreign key constraint)
• ml;ltizrupghu;j;jy;fl;Lg;ghL(A (table) check constraint)
46B.Christopaul (MSc, BSc)

47. Types of constrain
tsfl;Lj;jpl;l tiffs;
• ntw;WkWg;Gf;fl;Lg;ghL(A NOT NULL constrain)
– ntw;WkWg;Gf;fl;Lg;ghLvd;gJ ml;ltiznahd;wpd;epunyhd;wpy;my;yJgytw;wpy;ntw;W
ngWkhdq;fs;gjpTnra;ag;gLtijjilnra;fpwJ.
• jdpj;Jtfl;Lg;ghL(A unique constraint)
– jdpj;Jtfl;Lg;ghLvd;gJ xU ml;ltiznahd;wpd;xUmy;yJgy Gyq;fspy;xNujuT,d;ndhUKiwgjpT
nra;ag;gLjiyjLf;fpd;wJ.jdpj;Jtkw;Wk;Kjd;ikr;rhtpMfpadjdpj;Jtfl;Lg;ghLfSf;FcjTfpd;wd.
– cjhuzj;jpw;F>supplier ml;ltizapy;toq;Fdu;xUtiujdpj;Jtkhf,dq;fhz;gjw;Fxt;nthUtoq;FdUf;Fk;
milahsq;fhzp(identifier) toq;fg;gLfpd;wJ.,jd;%yk;xNumilahsq;fhzp,d;DnkhU toq;FdUf;F
toq;fg;glhkypUg;gij jdpj;Jtfl;Lg;ghLcWjpnra;fpwJ.
47B.Christopaul (MSc, BSc)

48. Types of constrain
tsfl;Lj;jpl;l tiffs;
• Kjd;ikr;rhtpf;fl;Lg;ghL (A primary key constraint)
– Kjd;ikr;rhtpf;fl;Lg;ghL vd;gJ jdpj;Jt fl;L;g;ghl;by; cs;sJ Nghd;wgz;Gfisf; nfhz;l xUmy;yJgyGyq;fspd;
Nru;f;ifahFk;.
– ml;ltizfSf;fpilapyhd njhlu;ig tiuaWf;f> Kjd;ikr;rhtpf;fl;Lg;ghl;ilAk;me;epar;rhtpf; fl;Lg;ghl;ilAk; ghtpf;fyhk;.
• me;epar;rhtpf; fl;Lg;ghL (A foreign key constraint)
– me;epar;rhtpf; fl;Lg;ghL vd;gJ xUmy;yJgy ml;ltizfspy; cs;s xUmy;yJgyGyq;fspd; ngWkhdk;gw;wpa ju;f;f
tpjpahFk;
– cjhuzj;jpw;F xU$l;Lj;jhdj;jpd; toq;Fdu;fsJ jfty;fis xUnjhFjp ml;ltizfs; gupkhwpf;nfhs;fpd;wd. toq;Fdu;
xUtupd;; ngau;mbf;fb khWgLfpd;wJ. ,jw;F Nkw;Nfhs;fl;Lj;jpl;nkhd;iw tiuaiwnra;ayhk;.xU
ml;ltizapypUf;Fk;toq;Fdupd; ID toq;Fdu; tpguq;fs; mlq;fpa ml;ltizapy; IDAld; nghUe;jf;$bajf,Uf;fNtz;Lk;.
,f;fl;Lg;ghL insert, update, or delete Nghd;w nray;fisfl;Lg;gLj;Jfpd;wJ.
48B.Christopaul (MSc, BSc)

49. Types of constrain
tsfl;Lj;jpl;l tiffs;
• ml;ltiz rupghu;j;jy;fl;Lg;ghL (A (table) check constraint)
– xUFwpj;j ml;ltizapy; Nru;f;fg;gLk;juTfSf;F fl;Lg;ghLfis tpjpf;fpd;wJ.
– cjhuzj;jpw;F (ml;ltiz) rupghu;j;jy;fl;Lg;ghL> gpuj;jpNaf jfty; mlq;fpa ml;ltizf;F rk;gs juTfs; Nru;f;fg;gLk;NghJ
my;yJ,w;iwg;gLj;Jk; NghJxUnjhopyhspf;Fupa rk;gsk;kl;lk;Mff; Fiwe;jJ $20000fshf cs;snjd;gij cWjp
nra;fpd;wJ.
• gq;Nfw;G fl;Lg;ghL (PARTICIPATION CONSTRAINT)
– xUnjhopyhsp jpizf;fsnkhd;wpw;fhf Ntiynra;aNtz;Lk;.
– xUnjhopyhsp vd;w cUnghUs;njhopy;Gupfpd;whu; vDk;njhlu;G epiyAld; gq;Nfw;Fk;NghJkhj;jpuNk
,Uf;f KbAk;
– me;j tifapy; mjdJ gq;Nfw;G KOikahdJ
– rpynjhopyhsp khj;jpuk;jpizf;fsq;fis Kfhikj;Jtk;nrafpd;wdu;. ,Jrhu;Gila gq;Nfw;ghFk;
49B.Christopaul (MSc, BSc)