
sambandhatmak bijganit

databases siddhantat, sambandhatmak bijganit haah eka siddhant aahe joou detache modelling karnyasathi bijganitiy sanrachanancha vapar karato aanee tyavar supratishthit shabdarthasah prashna paribhashit karato. haah siddhant edgar eff. yanni mandala hota. code.
sambandhatmak bijganitacha mukhya vapar mhanje sambandhatmak detabesesasathi, visheshtah asha detabesesasathi kweri bhashansathi, jyat ess. kyu. ell. heey pramukh aahe, saiddhantik paya pradan karane. sambandhatmak databases sambandh mhanoon darshavilelya saranibaddha detacha sanchayit karatat. relational detabesvaril prashna anekada relations mhanoon darshavilelya tabular detache pratinidhitva karatat. 
eka kinwa adhik input sambandhanche output sambandhat rupantar karananya operatorchi vyakhya karane haah relational bijganitacha mukhya uddesh aahe. heey operator sambandh input mhanoon swikartat aanee sambandh output mhanoon tayar karatat heey lakshat gheta, teey ekatra kele jaau shakatat aanee sambhavya guntaguntiche prashna vyakt karnyasathi vaparale jaau shakatat jeey sambhavyapane anek input sambandhanche (jyancha deta detabasemadhye sangrahit keela jaato) ekach output sambandhat (kweri nikal) rupantar karatat. 
unic operator input mhanoon ekach sambandh swikartat; udaharananmadhye input sambandhatun vishisht gunadharm (stambh) kinwa tupples (pankti) filter karnyasathi operatorcha samavesh hoto. 
binary operator input done sambandh mhanoon swikartat; udaharanarth, asha operator done input sambandh ekach output sambandhat ekatra karatat, udaharanarth, donhi sambandhanmadhye aadhalanare serve tooples gheuun, dusya sambandhat aadhalanaya pahilya sambandhatun tooples kadhoon takane, pahilya sambandhatil tooplescha vistar karane aanee vishisht attinshi julananya dusya sambandhatil tooples, aanee asech pudhe. 
itar adhik pragat operatorcha dekhil samavesh keela jaau shakato, jethe vishisht operatorcha samavesh kinwa vagalane algebranchya kutumbala janm dete.
parichay.
eae. chya prakashanaparyant shuddha ganitachya baher sambandhatmak bijganitekade farse laksh dile gele nahee.eff. 1970 madhye kodichya detache sambandhit model. kodeene databases kweri bhashansathi aadhar mhanoon asha bijganitacha prastav thewala. (amalbajavani vibhag pahaa.)
sambandhatmak bijganit heey tooples sootra _ 1 chya samaroop sanchanvar karya karate.
jethe aapan samanyatah m chaa arth tablemadhil panktinchi sankhya assa karato
aanee n hii stambhanchi sankhya asel. pratyek stambhatil serve nondi
tyach prakarcha.
kodachya bijganitache paach adim prachalak mhanje "nivad", "prakshepan", "cartasian utpadan" (jyala "cross utpadan" kinwa "cross join" asehi mhanatat), "seet union" aanee "seet farak".
operator seet qaraa.
sambandhatmak bijganit sanch siddhantatun sanch sangh, sanch farak aanee cartasian utpadan vaparte, parantu yaa prachalakanmadhye atirikt maryada jodate.
seet union aanee seet farkasathi, samavisht asalele done sambandh 'union-susangat' asane aavashyak aahe-mhanje, done sambandhanmadhye samaan gunadharmancha sanch asane aavashyak aahe. kaaran sanch chhedanbindu haah sanch sangh aanee sanch farkachya drushtine paribhashit keela jaato, sanch chhedanbindumadhye samavisht asalele done sambandh dekhil sangh-susangat asane aavashyak aahe.
cartasian utpad paribhashit karnyasathi, tyat samavisht asalelya done sambandhanmadhye parasparvirodhi shirshake asane aavashyak aahe-mhanje, tyanna samaan gunavishesh naav nasave.
yavyatirikt, cartasian utpadanachi vyakhya seet siddhantatil utpadanapeksha vegalya prakare yaa arthane kelee jaate qee operationchya uddeshansathi tupples "uthal" manale jaatat. mhanjech, 'm'-toopleschya sanchasah 'n'-toopleschya sanchachya cartasian utpadanatun 'sapat'-tooplescha sanch midato (tarr moolbhut sanch siddhantane 2-tooplescha sanch vihit keela asata, jyamadhye pratyekamadhye 'n'-tooples aanee 'm'-tooples asatat). adhik aupcharikpane, "r" × "s" chee vyakhya khalilpramane kelee aaheh
sootra _ 2
cartasian utpadanachi mukhyata hii tyachya ghatakanchya mukhyateche utpadan aahe, mhanje, ."aar" "×" "ess". = ."aar". × ."ess"..
prakshepan ().
prakshepan heey sootra _ 3 mhanoon lihilele eka eksandh karya aahe jethe sootra _ 4 haah gunavishesh navancha sanch aahe. asha prakshepanacha parinam haah sanch mhanoon paribhashit keela jaato joou jevha "r" madheel serve tupples sanch sootra _ 5 paryant maryadit asatat tevha prapt hoto.
teepah ess. kyu. ell. mankamadhye amalat aanalyavar "purvanirdharit prakshepan" sanchaivaji bahu-sanch parat karate aanee duplicate deta kadhoon taknyasathiche prakshepan cockoge _ 1 mukhya shabdachya jodanidware prapt hote.
nivad (σ).
samanyikrut nivad hii sootra _ 6 mhanoon lihileli eka eksandh kriya aahe, jethe eka prastavatmak sootra aahe jyamadhye samanya nivadimadhye parvanagi dilyapramane anoo aanee tarkik chalak (aanee), (kinwa) aanee (nakar) asatat. hii nivad 'aar' madheel tyaa serve tuppleschi nivad karate jyasathi dharan karate.
pattyapustiket serve mitranchi kinwa vyavsayik sahakanyanchi yadee midvanyasathi, nivad sootra 7 mhanoon lihili jaau shakate. parinam pratyek adviteey nondiche pratyek gunavishesh asalele sambandh asel jethe kharey aahe kinwa jethe kharey aahe.
("ρ") heey naav badalane.
naav badalane heey sootra _ 8 mhanoon lihilele eka ekatmak karya aahe jethe serve tupplesmadhil 'buub' gunavisheshache naav badaloon 'aaa' gunavishesh karane vagalata parinam 'aar' sarkhach asato. yacha vapar keval sambandh kinwa sambandhach yanchya gunavisheshache naav badalanyasathi keela jaato.
sambandhatil 'isfriend' gunavisheshache naav badaloon 'iss business contact' karnyasathi sootra _ 9 vaparale jaau shakate.
sootra _ 10 sanketan dekhil aahe, jethe "r" chey naav badaloon "x" kele jaate aanee gunavishesh sootra _ 5 chey naav badaloon sootra _ 12 kele jaate.
operatormadhye sameel vha aanee sameel vha.
naisargik jode (hutt).
natural join (heii) haah eka dviaadhari operator aahe joou ("r" heii ") mhanoon lihila jaato jethe" r "aanee" s "heey sambandh aahet. naisargik jodanicha parinam mhanje "aar" aanee "ess" madheel tuppleschya serve sanyojanancha sanch joou tyanchya samanya gunavisheshanchya navanvar samaan asato. udaharanarth, 'karmchari' aanee 'vibhag' yaa sarnyancha aanee tyanchya naisargik jodanicha vichar karah
lakshat ghya qee merrie navacha karmchari kinwa utpadan vibhag yapaiki kahihi nikalat disat nahee.
yacha vapar sambandhanchi rachana paribhashit karnyasathi dekhil keela jaau shakato. udaharanarth, "karmchari" aanee "vibhag" chee rachana hii varr darshavilyapramane tyanchi jodani aahe, jee sarvanvar prakshepit kelee jaate parantu samanya gunavishesh "vibhagnam" varr. shreni siddhantat, jode heey tantotant tantumay utpadan aahe.
natural join haah tarkshuddhapane sarvat mahattvachya operatorpaiki eka aahe kaaran too logical aanee operatorcha relational pratirup aahe. lakshat ghya qee jarr aanee dware jodalelya done vidheykanpaiki pratyekamadhye samaan chull disun aale tarr teey chull ekach goshtisathi aahe aanee donhi swaroop nehmi samaan moolyane badalale jaane aavashyak aahe (haah tarkik aanee chya idempotancecha parinam aahe). visheshtah, naisargik jodanyamule paradeshi killidware sambandhit asalelya sambandhanche sanyojan shakya hote. udaharanarth, vareel udaharanamadhye kadachit 'karmchari' chee parkeey killi asel."vibhag" teey "vibhag"."vibhagnam" aanee nantar "karmchari" aanee "vibhag" chey naisargik jode serve karmchanyanna tyanchya vibhaganshi jodate. heey karya karate kaaran fauren qee tyach navachya gunadharmanmadhye asate. jarr asey nasel tarr "vibhag" madheel paradeshi killipramane."vyavasthapak" teey "karmchari"."naav" nantar naisargik jode ghenyapurvi yaa stambhanche naav badalane aavashyak aahe. asha jodyala kadhikadhi equizoin asehi mhanatat ("θ"-jode pahaa).
adhik aupcharikpane naisargik jodaniche shabdarth khalilpramane paribhashit kele aaheth
jethe 'funn (tii)' heey eka vidhey aahe jeey 'tii' (ganiteey arthane) yaa sambandhasathi kharey aahe, jarr 'tii' heey eka karya asel (mhanje, 'tii' heey konatyahi gunavisheshala anek mulyancha nakasha karat nahee). samanyatah heey aavashyak asate qee "r" aanee "s" madhye kiman eka samaan guna asane aavashyak aahe, parantu jarr hii maryada vagalali gelee aanee "r" aanee "s" madhye samaan gunavishesh nastil, tarr naisargik jodani nemke cartasian utpadan banate.
naisargik jodaniche anukaran khalilpramane kodichya adim saha kele jaau shakate. asey gruheet dhara qee "see" 1.., see" "emm" hii "aar" aanee "ess", "aar" 1 sathee samanya gunadharm nave aahet.., aar" aine "heey aahet
aar" aanee "ess" 1 sathee adviteey gunavishesh nave.., s" "k" heey aahet 
s" sathee adviteey gunadharm nave. shivay, asey gruheet dhara qee gunavisheshachi nave "x" 1 aahet..x" "m" heey "r" kinwa "s" madhye naheet ". pahilya tappyat 's' madheel samanya gunavisheshanchi nave punha namantar kelee jaau shakatatah
mug aapan cartasian utpadan gheto aanee jodale jaanare tooples nivadatoh
shevati aapan punarnamit kelelya gunadharmanpasun mukt honyasathi eka prakshepan karatoh
"θ"-joda aanee sambhag qaraa.
qaar aanee botinche namune aanee tyanchya sambandhit kimmati soochibaddha karananya 'qaar' aanee 'boat' yaa sarnyancha vichar qaraa. samaja ekhadya grahakala qaar aanee boat vikat ghyayachi aahe, parantu teela karpeksha botisathi jaast paise kharch karayache naheet. carprise' ± 'boatprice' yaa vidheyavaril 'θ'-join (θ) 'heey vidhey purn karananya panktinchya sapat jodya tayar karate. guna samaan aahet ashee aut vapartana, udaharanarth kimmat, tevha aut "kimmat" = "kimmat" mhanoon nirdisht kelee jaau shakate."
kinwa paryayi ("kimmat") swatach.
done sambandhanmadhil tupples ekatra karnyasathi jethe sanyojanachi aut keval samayik gunadharmanchi samanata nahee tarr join operatorche adhik samanya swaroop asane soyiche aahe, jeey "θ"-join (kinwa theeta-join) aahe. θ"-join haah eka dviaadhari operator aahe joou sootra _ 13 kinwa sootra _ 14 mhanoon lihila jaato jithe "a" aanee "b" hii gunavishesh nave aahet, "θ" heey sanchatil dviaadhari sambandhatmak operator aahe}, "y" heey moolya sthirank aahe aanee "r" aanee "s" heey sambandh aahet. yaa operationchya parinamanmadhye "r" aanee "s" madheel tuppleschya serve sanyojanancha samavesh asato jeey "θ" chey samadhan karatat. s" aanee "r" chey shirshake visangat asateel, mhanje tyat samaan gunank nasel tarach "θ"-joincha parinam paribhashit keela jaato.
tyamule moolbhut karyanmadhye yaa karyache anukaran khalilpramane aaheh
jarr operator "θ" haah equality operator (=) asel tarr yaa joinla equizoin dekhil mhanatat.
tathapi, lakshat ghya qee natural join aanee selection operatorsna samarthan denanya sanganak bhashela 'θ'-joinchi dekhil aavashyakta nahee, kaaran heey natural joinchya parinami nivadidvare sadhya kele jaau shakate (jeey jevha samayik gunadharm nasatat tevha cartasian utpadanat rupantarit hote).
ess. kyu. ell. amalbajavanimadhye, vidheyavar jodanyala sahasa 'inner join' mhanatat aanee 'aun' mukhya shabd ranganna filter karnyasathi vaparlya jaanarya vidheyala nirdisht karnyas anumati deto. heey lakshat ghene mahatvache aaheh sapat cartasian utpadan tayar karane aanee nantar pankti galane sankalpanatmakdrushtya yogya aahe, parantu amalbajavani join kwerila gatee denyasathi adhik atyadhunik deta structurecha vapar karel.
ardhjoin (aanee).
davikadil ardhjoda haah naisargik joda sarkhach jode aahe aanee sootra 15 mhanoon lihila jaato jethe sootra 16 aanee sootra 17 heey sambandh aahet. tyacha parinam mhanje sootra _ 16 madheel serve tupplescha sanch aahe jyasathi sootra _ 17 madhye eka tupples aahe joou tyanchya samanya gunavisheshanchya navanvar samaan aahe. naisargik jodanipeksha farak assa aahe qee sootra _ 17 chey itar stambh disat naheet. udaharanarth, 'karmchari' aanee 'vibhag' aanee tyanchya ardhjodichya sarnyancha vichar karah
adhik aupcharikpane ardhjodichya shabdarthanchi vyakhya ashee kelee jaau shakate
khalilpramaneh
sootra _ 21
jethe sootra _ 22 heey naisargik jodanichya vyakhyepramane aahe.
naisargik jode vaparoon semijoinche anukaran khalilpramane kele jaau shakate. jarr sootra _ 23 heey sootra _ 16 chey gunavishesh nave asateel, tarr
sootra _ 25
aapan moolbhut operators natural joinche anukaran karoo shakato, tyamule heey semijoinsathi dekhil lagoo hote.
kodachya 1970 chya peparmadhye, semijoinla nirbandh mhanatat.
antizoin (Â).
antizoin, 'aar' mhanoon lihilele, jethe 'aar' aanee 'ess' heey sambandh aahet, teey semijoinsarkhech aahe, parantu antizoincha parinam keval 'aar' madheel tyaa tupplescha asato jyasathi 'ess' madhye 'noow' tupples asatat jeey tyanchya samanya gunavisheshanchya navanvar samaan asatat.
udaharanarth, 'karmchari' aanee 'vibhag' aanee tyanchya 'karmchari' yaa sarnyancha vichar qaraa.
antijoinh
antijoinchi aupcharik vyakhya khalilpramane kelee jaateh
kinwa
jethe naisargik jodanichya vyakhyepramane aahe.
antijoinchi vyakhya ardhajodache purak mhanoon dekhil kelee jaau shakate, khalilpramaneh
heey lakshat gheta, antizoinla kadhikadhi anty-semizoin mhanatat aanee antizoin operatorla kadhikadhi semizoin chinh mhanoon lihile jaate, jyachya varr eka patti asate, tyaeivaji.
vibhagani (ρ).
vibhajan heey eka dwaiti operation aahe jeey "r" ρ "s" mhanoon lihile jaate. vibhagani thet ess. kyu. ell. madhye lagoo kelee jaat nahee. parinamanmadhye 'aar' madheel tupplesche nirbandh aanee 'aar', aay 'sathee adviteey asalelya gunavisheshanchya navanche nirbandh asatat.eae., 'r' chya shirshakat parantu 's' chya shirshakat nahee, jyasathi teey asey manate qee 's' madheel tupples tyanche serve sanyojan 'r' madhye aahet. udaharanarth, 'purn', 'dii. bii. prakalp' aanee tyanche vibhajan hii saranya pahah
jarr 'dii. bii. prakalp' madhye databases prakalpachi serve kaame asateel, tarr vareel vibhaganichya nikalat nemke teey vidyarthi asateel jyanni databases prakalpatil donhi kaame purn kelee aahet.
adhik aupcharikpane vibhajanache shabdarth khalilpramane paribhashit kele aaheh jethe {"a" 1.., a" "n" "} haah" "r" "aanee" "t" ["" a "" 1 sathee adviteey asalelya gunavishesh navancha sanch aahe ".., a" "n"] heey yaa sanchasathi "" t "chey bandhan aahe". samanyatah heey aavashyak asate qee 's' chya shirshakamadhil gunavisheshanchi nave 'r' chya upasanchatil asaveet kaaran anyatha operationcha parinam nehmich rikama asel.
moolbhut karyansah vibhajanache anukaran khalilpramane aahe. aapan asey gruheet dharato qee "aaa" 1.., aaa" "aine" hii "" aar "" aanee "" bii "" 1 sathee adviteey gunavishesh nave aahet ".., b" "m" hii "s" chee gunavishesh nave aahet ". pahilya tappyat aapan tyachya adviteey gunavisheshanchya navanvar 'aar' prakshepit karato aanee 'ess' madheel tupples serve sanyojan tayar karatoh
aadhichya udaharanat, tii heey eka table asey darshavel qee pratyek vidyarthi (vidyarthi hii purn kelelya tablechi adviteey killi/gunavishesh asalyamule) pratyek dilelya karyasah jodala jaeel. udaharanarth, yujeenmadhye done pankti asateel, yujeen → databases 1 aanee eugene → databases 2 tii madhye.
 pudhil tappyat aapan 'tii' madhoon 'aar' vaja karato." 
sambandhah
yuu' madhye aamchyakade shakya aahe
jeey sanyojan 'aar' madhye asoo shakale asate, parantu navhate. 
 mhanoon jarr aata aapan "r" sathee adviteey asalelya gunavisheshanchya navanvar prakshepan ghetale tarr"
mug aamchyakade 'aar' madheel tupplesche nirbandh aahet jyasathi nahee
s' madheel tupples serve sanyojan 'r' madhye upasthit hoteh
tyamule kaay karayache aahe teey mhanje tyavar 'aar' chaa prakshep ghene
adviteey gunavishesh nave aanee "v" madheel nave vaja karah
samanya vistar.
vyavharat varr varnan kelele shastriy sambandhatmak bijganit bahya jodya, ektrit karye aanee agadi sankramanshil bund yasarkhya vividh karyansah vistarit kele jaate.
bahya jodani.
jodanichya (kinwa aateel jodanichya) parinamanmadhye done operandmadhil julananya tuppleschya sanyojanadvare tayar jhalelya tupples asatat, tarr bahya jodyamadhye tyaa tupples asatat aanee yavyatirikt eka operandmadhil atulaneey tupplescha vistar karoon tayar jhalelya kahee tupples asatat. bahya jodya yaa aataparyant charcha kelelya shastriy sambandhatmak bijganitacha bhag manalya jaat naheet.
yaa vibhagat paribhashit kelele operator, bharnyachya mulyansathi vaparlya jaananya "null" mulyache astitva gruheet dharatat, jeey aapan paribhashit karat nahee, jeey pratyakshat ess. kyu. ell. madheel nalshi sambandhit aahe. parinami tableveryl tyanantarchya nivad karyanna arthpurn banavanyasathi, shoonyanna shabdarth arth dene aavashyak aahe; kodachya drushtikonatun nivadidvare vaparlele prastavatmak tark teen-mulyanchya tarkshastraparyant vistarit kele jaate, jaree aapan yaa lekhat teey tapasheel vagalato.
teen bahya jode sanvahak paribhashit kele jaatatah daway bahya jode, ujave bahya jode aanee purn bahya jode. ('bahya' haah shabd kadhikadhi vagalala jaato.)
davikadil bahya jode (′).
davya bahya jodanila 'r' s 'asey lihile jaate jethe' r 'aanee' s 'heey sambandh aahet. davya bahya jodanicha parinam mhanje 'aar' aanee 'ess' madheel tuppleschya serve sanyojanancha sanch aahe jeey tyanchya samanya gunavisheshanchya navanvar samaan aahet, yavyatirikt (shithilpane sangayache tarr) 'aar' madheel tupples jyanna 'ess' madhye julanare tupples naheet.
udaharanarth, 'karmchari' aanee 'vibhag' aanee tyanchya davya bahya jodanicha vichar karah
parinami honanya sambandhat, 's' madheel jyaa tuppleschi samanya gunavisheshanchya navanmadhye samaan moolye nasatat aanee 'r' madheel tuppleschi 'null' moolya asate, ω.
vitt" kinwa "karyakari" yaa "vibhagnamasah" vibhagat "konatehi tooples naslyamule, parinami sambandhat ωs udbhavtat jethe" karmchari "madheel tupalsmadhye" vitt "kinwa" karyakari "chey" vibhagnam "asate.
r" 1 ", r" 2, asey samajooya..., r" "n" heey "r" yaa sambandhache gunadharm asateel aanee {("ω", asey asoo dya..., ω")} haah ekvachani asoo dya
sambandh 's' shhee 'adviteey' asalelya gunadharmanvar sambandh (jeey 'r' chey gunavishesh naheet). mug davya bahya jodyache varnan naisargik jodanichya drushtine (aanee mhanoon moolbhut operatorcha vapar karoon) khalilpramane kele jaau shakateh
ujavikade bahya jodane (′).
ujavya bahereel jodani davya bahereel jodanishi jawaljawal sarkhich vagate, parantu tablechya bhoomika badalalya jaatat.
r" aanee "s" yaa sambandhancha ujava bahya sanyog "r" ′s "mhanoon lihila jaato. ujavya bahya jodanicha parinam mhanje "r" aanee "s" madheel tuppleschya serve sanyojanancha sanch aahe, jeey tyanchya samanya gunavisheshanchya navanvar samaan aahet, yashivay "s" madheel tupples jyanna "r" madhye julanare tupples naheet.
udaharanarth, 'karmchari' aanee 'vibhag' aanee tyanchya 'karmchari' yaa sarnyancha vichar qaraa.
ujavikadil bahya jodanih
parinami sambandhat, 'r' madheel jyaa tuppleschi samanya gunavisheshanchya navanmadhye samaan moolye nasatat, jyachya 's' madheel tupples 'null' moolya ghetat, ω.
karmchari" madhye "utpadan" chya "vibhagnam" saha konatehi tooples naslyamule, ωs heey navat aadhaltat aanee parinami sambandhanchya gunavisheshanna anukool karatat jethe "vibhag" madheel tupalsmadhye "utpadan" chey "vibhagnam" hote.
chala "s" 1 "," s "2..., s" n "heey sambandh" s "chey gunadharm asateel aanee {(" ω ", asey asoo dya..., ω")} haah ekvachani asoo dya
aar" yaa sambandhasathi "adviteey" asalelya gunadharmanvaril sambandh (jeey "ess" chey gunavishesh naheet). mug, davya bahya jodapramane, ujavya bahya jodyache naisargik jode vaparoon khalilpramane anukaran kele jaau shakateh
purn bahya jode (′).
bahya jode kinwa purn bahya jode parinam mhanoon davya aanee ujavya bahya jodyanche parinam ekatra karate.
purn bahya jode 'aar' ess 'mhanoon lihili jaate jethe' aar 'aanee' ess 'heey sambandh aahet. purn bahya jodanicha parinam mhanje 'aar' aanee 'ess' madheel tuppleschya serve sanyojanancha sanch aahe, jeey tyanchya samanya gunavisheshanchya navanvar samaan aahet, yashivay 'ess' madheel tupples jyanna 'aar' madhye julanare tupples naheet aanee 'aar' madheel tupples jyanna tyanchya samanya gunavisheshanchya navanmadhye 'ess' madhye julanare tupples naheet.
udaharanarth, 'karmchari' aanee 'vibhag' aanee tyanchya 'karmchari' yaa sarnyancha vichar qaraa.
purn bahya jodah
parinami sambandhat, 'r' madheel jyaa tuppleschi samanya gunavisheshanchya navanmadhye samaan moolye nasatat, jyachya 's' madheel tupples 'null' moolya ghetat, ω. s" madheel jyaa tuppleschi samanya gunavisheshanchya navanmadhye samaan moolye nasatat aanee jyachya "r" madheel tupples dekhil "null" moolya ghetat, ω ".
sampoorn bahya jodaniche anukaran davya aanee ujavya bahya jodyancha vapar karoon kele jaau shakate (aanee mhanunach naisargik jodani aanee seet union) khalilpramaneh
domain gananesathi operations.
aataparyant sadar kelelya sambandhatmak bijganitemadhye asey kahihi nahee jeey deta domenvar ganana karnyas anumati deil (samanatesah prastavit abhivyaktinchya mulyankanavyatirikt). udaharanarth, done stambhanmadhil sankhyanna gunakar karnari abhivyakti lihinyasathi aataparyant sadar kelelya keval bijganitacha vapar karane shakya nahee, eae.jee. ekoon kimmat midvinyasathi pramanasah eka ekak kimmat. vyavharik prashna bhashanmadhye asha suvidha aahet, udaa.jee. ess. kyu. ell. nivad, nikalatil naveen stambhanchi vyakhya karnyasathi ankganitiy karyanna parvanagi dete, unit _ price * praman nivada, heey tii pasoon ekoon _ kimmat mhanoon, aanee tatsam suvidha, dii 'sha cockoge _ 2 yaa mukhya shabdadvare adhik spashtapane pradan kelee jaate. databases siddhantat yala vistarit prakshepan mhanatat.
ektrikaran.
shivay, stambhavaril vividh karyanchi ganana karane, jase qee tyachya ghatakanchi berries karane, heey dekhil aataparyant sadar kelelya sambandhatmak bijganitacha vapar karoon shakya nahee. paach ekoon karye aahet jee bahutek sambandhit databases pranalinmadhye samavisht aahet. yaa kriya berries, ganana, sarasari, kamal aanee kiman aahet. sambandhatmak bijganitemadhye, eka yojnavar ("a" 1 ", a" 2,) ektrikaran karya... "aaa" "aine" ") khalilpramane lihile aaheh
jethe pratyek "a" "j", 1 ≤ "" j "≤" k ", heey mool gunadharmanpaiki eka aahe" a "" i ", 1 ≤" i "≤" n ".
jee" chya aadhiche gunadharm mhanje gunanche gut karane, jeey ess. kyu. ell. madheel "gatadware" khandasarkhe karya karatat. mug vaiyaktik gunadharmanvar ektrikaran karyanchi aniyantrit sankhya lagoo kelee jaate. operation heey "aar" yaa aniyantrit sambandhavar lagoo kele jaate. gatbaddh vaishishtye aichchhik aahet aanee jarr tee puravali gelee naheet, tarr ektrikaran karye jyaa sampoorn sambandhat operation lagoo kele jaate tyaa sampoorn sambandhat lagoo kelee jaatat.
asey gruheet dharuya qee aaplyajaval teen stambh asaleli eka sarani aahe, mhanje aanee. aamhala pratyek shakhechi kamal shillak shodhayachi aahe. heey "g" kamal () () dware purn kele jaate. shakha kahihi asso, serve khatyanmadhye sarvoch shillak shodhanyasathi aapan fakt 'jee' kamal () () asey lihu shakato.
tyaeivaji gatlekhan anekada "γ" max () () asey lihile jaate.
sankramanshil bund.
jaree sambandhsambandhi bijganit bahutek vyavharik hetunsathi purese shaktishali vatat asale, taree sambandhanvar kahee sope aanee naisargik sanchalak aahet jeey sambandhsambandhi bijganitadvare vyakt kele jaau shakat naheet. tyapaiki eka mhanje dwaiti sambandhanche sankramanshil samapan. d" heey kshetra dile tarr dwaiti sambandh "r" haah "d" × "d" chaa upasanch asoo dya. aar' chaa sankramanshil bund 'aar +' haah 'dii' × 'dii' chaa sarvat lahan upasanch aahe jyamadhye 'aar' aahe aanee khaleel aut purn karateh
r" laa chull yuktivad mhanoon ghetalele konatehi sambandhatmak bijganit abhivyakti "e" ("r") nahee jeey "r" + tayar karate heey yaa vastusthiticha vapar karoon siddha kele jaau shakate.
ess. kyu. ell. matra 1999 pasoon asha nishchit bindu prashnanna adhikrutpane samarthan dete aanee tyapurvi yaa dishene vikretya-vishisht vistar hote.
kweri optimizationsathi bijganitiy gunadharmancha vapar.
sambandhit databases vyavasthapan pranalinmadhye anekada kweri optimizercha samavesh asato, joou dilelya kwerichi amalbajavani karnyacha sarvat karyaksham marg tharvanyacha prayatna karato. kweri optimizers sambhavya kweri yojana mojatat, tyanchya kharchacha andaj lavtat aanee sarvat qamee andajit kharchasah yojana nivadatat. jarr prashna relational bijganitetil prachalkandware darshavile gele asateel, tarr kweri optimizer yaa prachalakanchya bijganitiy gunadharmancha vapar karoon prarambhik prashna punha lihoon sambhavya prashna yojananchi ganana karoo shakato.
prashna heey eka vruksh mhanoon darshavile jaau shakatat, jethe
kweri optimizerche prathamik uddisht mhanje expression treaseche samatulya expression treasemadhye rupantar karane, jethe treamadhil up-expressiondware milananya sambandhancha sarasari aakar optimizationpurvichya tulanet lahan asato. ekach prashnat samanya up-abhivyakti tayar karnyacha prayatna karane kinwa tyaa serve prashnanmadhye ekach velee ekapeksha jaast prashnanche moolyankan kele jaat asalyas, heey duyyam uddisht aahe. dusya dhyeyamagil tark assa aahe qee ekada samanya up-abhivyakti mojane purese aahe aanee parinam tyaa up-abhivyakti asalelya serve prashnanmadhye vaparale jaau shakatat.
asha badalanmadhye vaparale jaau shakanare niyam yethe aahet.
nivad.
nivad sanchalkambaddalche niyam kweri optimizationmadhe sarvat mahatvachi bhoomika bajavtat. nivad haah eka operator aahe joou tyachya operandmadhil panktinchi sankhya atishay prabhavipane qamee karato, mhanoon jarr abhivyakti vrukshatil nivad panankade halavali gelee tarr antargat sambandh (up-abhivyaktidvare milanare) bahudha qamee hotil.
moolbhut nivad gunadharm.
nivad hii prabhavi aahe (ekach nivadichya anek anuprayogancha pahilya paryayachya palikade konatahi atirikt parinam hott nahee) aanee parivartaneey (aurder nivadicha antim nikalavar konatahi parinam hott nahee).
jatil paristhitinsaha nivadiche vibhajan qaraa.
eka nivad jyanchi sthitee sopee paristhiti aahe tee tyach vaiyaktik paristhitisaha nivadichya kramashi samatulya aahe aanee jyachi aut vichhedan aahe tee nivad nivadanchya sanyogashi samatulya aahe. yaa olakhincha vapar nivadi villin karnyasathi keela jaau shakato jenekarun qamee nivadiche moolyankan karane aavashyak aahe kinwa tyanche vibhajan karane jenekarun ghatak nivad swatantrapane halavata yeteel kinwa anukool karata yeteel.
nivad aanee mishra utpadan.
cross product heey moolyankan karnyasathi sarvat mahag operator aahe. jarr input sambandhanmadhye "n" aanee "m" olee asateel, tarr nikalat sootra _ 34 pankti asateel. tyamule, cross product operator lagoo karnyapurvi donhi operandcha aakar qamee karane mahatvache aahe.
jarr cross productchya nantar selection operator, udaa. asel tarr heey prabhavipane kele jaau shakate.jee. sootra _ 35. jodanyachi vyakhya vicharat gheta, heey sarvat sambhavya prakaran aahe. jarr cross productche anusaran selection operator karat nasel, tarr aapan itar selection niyam vaparoon expression treachya uchch staranmadhun selection khalee dhakalanyacha prayatna karoo shakato.
vareel prakaranat, klisht nivad atimbaddal vibhajan niyam vaparoon 'aaa' atinche vibhajan 'buub', 'see' aanee 'dii' atinmadhye kele jaate, jenekarun sootra _ 36 aanee 'bii' madhye fakt 'aar' madheel gunavishesh asatat, 'see' madhye fakt 'pii' madheel gunavishesh asatat aanee 'dii' madhye 'aii' chaa bhag asato jyamadhye 'aar' aanee 'pii' yaa donhimadhil gunavishesh asatat. lakshat ghya qee, 'buub', 'see' kinwa 'dii' bahudha rikame aahet. mug khalilpramaneh
nivad aanee sanch operator.
nivad hii sanch farak, chhedanbindu aanee sangh chalkanvar vitaranatmak asate. khaleel teen niyam expression treamadhil seet operationschya khalee nivadila dhakalanyasathi vaparale jaatat. sanch farak aanee chhedanbindu prachalkansathi, parivartananantar fakt eka karyasanchavar nivad prachalak lagoo karane shakya aahe. jethe eka operand lahan asel tithe heey fayadeshir tharoo shakate aanee nivad operatorche moolyankan karnyache overhead operand mhanoon lahan sambandh vaparnyachya fayadhyanpeksha jaast aahe.
nivad aanee prakshepan.
nivad sthiteet sandarbhit kshetre hii prakshepanatil kshetrancha upasanch asel tarach nivad prakshepanasah pravas karate. jarr operand heey cross product asel kinwa join asel tarr prakshepanapurvi nivad karane upayukt tharoo shakate. itar prakarananmadhye, jarr nivad sthitee mojanyasathi tulanene mahag asel, tarr prakshepanabaher nivad halavalyane chachani karane aavashyak asalelya tuppleschi sankhya qamee houu shakate (kaaran vagalalelya kshetranmule duplicates kadhoon takalyamule prakshepan qamee tupples tayar karoo shakate).
prakshepan.
moolbhut prakshepan gunadharm.
prakshepan heey saksham aahe, jenekarun (vaidh) prakshepananchi malika sarvat bahereel prakshepanaitaki asel.
prakshepan aanee sanch operator.
prakshepan heey sanch sangharajyapeksha vitaranatmak asate.
prakshepan chhed aanee nirdharit farkavar vitarit hott nahee. pratidarshane khalilpramane dilee jaatatah
aanee
jethe "buub" heey yapeksha vegale asalyache manale jaate.
naav badalane.
moolbhut punarnamit gunadharm.
chalanchi salag nave ekach punarnamat modali jaau shakatat. jyaa kriyanmadhye konatehi chull samaan nasatat, tyanna parasparanchya sandarbhat manmane punarkramit kele jaau shakate, jyancha vapar karoon shejari salag punarnamkarane kelee jaau shakatat jenekarun teey kosaloo shaktil.
operatorche naav badaloon seet qaraa.
punarnamit heey sanch farak, sangh aanee chhedanbinduvar vitaranatmak aahe.
utpadan aanee sangharajya.
cartasian utpadan heey vitaranatmak aahe.
amalbajavani.
kodachya bijganitavar aadharit pahili prashna bhasha alfa hotee, jee dow. swatah code. tyanantar, isable tayar karnyat aale aanee yaa agraganya karyache anek adhikaanyaanee kautuk kele aahe qee tyanni kodachya kalpanela upayukt bhashet rupantarit karnyacha marg dakhavala aahe. vyavasay pranali 12 hii alpakalin udyog-shakti sambandhit dii. bii. emm. hotee jee aay. ess. bii. ell. chya udaharananantar hotee.
1998 madhye khris dett aanee hyoog darwen yanni sambandhit databases siddhant shikavanyasathi vaparnyasathi tutorial dii navachi bhasha prastavit kelee aanee tichi prashna bhasha dekhil isblechya kalpananvar aadharit aahe. aar. ell.' hii 'dii' yaa shikavanichi amalbajavani aahe.
ess. kyu. ell. chee prashna bhasha dekhil sapeksh bijganitavar aadharit aahe, jaree ess. kyu. ell. (saranya) madheel karyapaddhati tantotant sambandh nasatat aanee sambandhatmak bijganitabaddalache anek upayukt pramey ess. kyu. ell. pratirupat nasatat (tarkshuddhapane anukulak aanee/kinwa vaparkartyanna haanee pohochavanyasathi). ess. kyu. ell. table model heey sanchapeksha eka pishavi (bahu-sanch) aahe. udaharanarth, sootra 54 heey samikaran sanchavaril sambandhatmak bijganitache eka pramey aahe, parantu pishvyanvaril sambandhatmak bijganitesathi nahee; pishvyanvaril sambandhatmak bijganitechya upcharasathi garcia-molina, ulman aanee vidom yanchya "sampoorn" pathyapustakacha adhyay 5 pahaa.
pudhe vacha.
vyavharikdrushtya detabesvaril konatyahi shaikshanik pathyapustakamadhye abhijat sambandhatmak bijganitacha tapshilvar abhyas asato.