Mndandanda wa mawu akuti "ubale" kapena "ubale" umatanthauzira njira yomwe deta yomwe ili mu matebulo imagwirizanitsidwa.
Otsatira ku mazambiri a dziko nthawi zambiri amavutika kuona kusiyana pakati pa database ndi spreadsheet. Amawona matebulo a deta ndikuzindikira kuti mazenerawa amakulolani kupanga ndi kufufuza deta m'njira zatsopano, koma amalephera kumvetsa tanthauzo la maubwenzi pakati pa deta yomwe imapereka teknoloji yachiyanjano.
Ubale umakulolani kuti mufotokoze mgwirizano pakati pa mitundu yosiyanasiyana yamagulu azinthu zamakono mwa njira zamphamvu. Ubalewu ukhoza kuyendetsedwa kuti upange mafunso amphamvu a pamtengowu, omwe amadziwika kuti akulowa.
Mitundu ya Maubwenzi Othandizira
Pali mitundu itatu yosiyana ya maubwenzi a deta, aliyense wotchulidwa malinga ndi chiwerengero cha mizere yomwe ingakhale yogwirizana. Chimodzi mwa mitundu itatuyi ya ubale ilipo pakati pa matebulo awiri.
- Ubale umodzi ndi umodzi umachitika pamene aliyense alowa mu tebulo yoyamba ali ndi imodzi, ndi imodzi yokha, mgwirizano mu tebulo lachiwiri. Ubale umodzi ndi umodzi sukugwiritsidwa ntchito kawirikawiri chifukwa nthawi zambiri zimakhala zosavuta kuyika zonse zomwe zili mu tebulo limodzi. Olemba malonda ena amagwiritsira ntchito mwayi umenewu pogwiritsa ntchito matebulo omwe ali ndi gawo la data kuchokera pa tebulo lina.
- Ubale umodzi ndi ambiri ndiwo mtundu wodalirika wa chiyanjano. Zimapezeka pamene zolemba zonse mu Table A zikugwirizana ndi zolemba chimodzi kapena zambiri mu Table B, koma zolembera zonse mu Table B zikufanana ndi zolembera imodzi m'magawo A. Mwachitsanzo, mgwirizano pakati pa tebulo la aphunzitsi ndi ophunzira a pulogalamu ya pulayimale Ma deta akhoza kukhala mgwirizano wapamodzi, chifukwa wophunzira aliyense ali ndi mphunzitsi mmodzi, koma mphunzitsi aliyense ali ndi ophunzira ambiri. Chojambula chimodzi ndi zambiri chimathandiza kuchotsa deta yosawerengeka.
- Ubale wochuluka kwa ambiri umachitika pamene zolemba zonse mu Table A zikugwirizana ndi zolemba chimodzi kapena zambiri mu Table B, ndipo mbiri iliyonse mu Table B ikufanana ndi zolemba chimodzi kapena zambiri mu Table A. Mwachitsanzo, mgwirizano pakati pa aphunzitsi ndi maphunziro tebulo ikhoza kukhala yochuluka kwa ambiri chifukwa mphunzitsi aliyense angaphunzitse maphunziro oposa umodzi, ndipo maphunziro aliwonse angakhale ndi ophunzitsa oposa mmodzi.
Kuyanjanitsa Zokhudza Ubale: Nkhani Yapadera
Maubwenzi odziwonetsera okha amapezeka pamene pali tebulo limodzi lokha lomwe likukhudzidwa. Chitsanzo chimodzi chodziwika ndi gome la antchito lomwe liri ndi zambiri zokhudza woyang'anira aliyense wogwira ntchito. Woyang'anira aliyense ndi wantchito ndipo ali ndi woyang'anira wake. Pankhaniyi, pali chiyanjano chokhazikika payekha, monga wogwira ntchito aliyense ali ndi woyang'anira mmodzi, koma woyang'anira aliyense akhoza kukhala ndi antchito angapo.
Kupanga Ubale ndi Zachilendo Zachilendo
Inu mumapanga ubale pakati pa matebulo powatchula makiwo akunja . Nthawi zambiri, mndandanda wa Table A uli ndi mafungulo oyambirira omwe amapezeka pa Table B.
Taganiziraninso chitsanzo cha Aphunzitsi ndi Ophunzira akulemba. Tebulo la Aphunzitsi liri ndi chidziwitso, dzina, ndi gawo la maphunziro:
InstructorID | Teacher_Name | Inde |
---|---|---|
001 | John Doe | Chingerezi |
002 | Jane Schmoe | Masamu |
Ophunzira akuphatikizapo chidziwitso, dzina, ndi chikho chachilendo chachilendo:
Wophunzira | Wophunzira_Name | Mphunzitsi_FK |
---|---|---|
0200 | Lowell Smith | 001 |
0201 | Brian Short | 001 |
0202 | Corky Mendez | 002 |
0203 | Monica Jones | 001 |
Mutu Walimu_FK mu Ophunzila amapepala ofotokozera mfundo zofunika kwambiri za wophunzitsa mu tebulo la Aphunzitsi.
Kawirikawiri, olemba masitepe amatha kugwiritsa ntchito "PK" kapena "FK" mu dzina la mndandanda kuti azindikire mosavuta chinsinsi choyambirira kapena chigawo chachilendo chakunja.
Onani kuti magome awiriwa akusonyeza mgwirizano umodzi pakati pa aphunzitsi ndi ophunzira.
Ubale ndi Zowonetsera
Mukangowonjezera makiyi akunja ku gome, mukhoza kupanga zolemba zapamwamba zomwe zimatsimikizira kukhulupirika kwanu pakati pa matebulo awiriwo. Izi zimatsimikizira kuti maubwenzi pakati pa matebulo amakhalabe osagwirizana. Pamene tebulo limodzi liri ndi fungulo lachilendo ku gome lina, lingaliro la kufotokozera umphumphu limanena kuti makiyi aliwonse akunja amtengo wapatali mu Table B ayenera kutanthauzira ku chiwerengero chomwe chilipo mu Table A.
Kugwiritsa Ntchito Ubale
Malingana ndi deta yanu, mumagwirizanitsa mgwirizano pakati pa matebulo m'njira zosiyanasiyana. Microsoft Access imapereka wizard yomwe imakulolani kuti mumagwirizanitse matebulo komanso kuti mukhazikitse kukhulupirika kwanu.
Ngati mukulemba SQL mwachindunji, mutha kulenga tebulo aphunzitsi, kulengeza ndondomeko ya ID kukhala chinsinsi chachikulu:
DZIWANI MAPHUNZIRO Aphunzitsi (
InstructorID INT AUTO_INCREMENT PRIMARY KEY,
Teacher_Name VARCHAR (100),
Chifukwa VARCHAR (100)
);
Mukamapanga Ophunzira Patebulo, mumalengeza chikhomo cha Teacher_FK kukhala chinsinsi chachilendo chomwe chikufotokozera gawo la InstructorID mu tebulo la aphunzitsi:
DZIWANI ZINTHU Ophunzira (
Ophunzira Ophunzira MU AUTO_INCREMENT PRIMARY KEY,
Student_Name VARCHAR (100), Teacher_FK INT,
KUKHALA KWAMBIRI (Teacher_FK) REFERENCES Aphunzitsi (InstructorID))
);
Kugwiritsa Ntchito Maubwenzi Kuti Aphatikize Ma Tebulo
Mukadapanga ubale umodzi kapena angapo m'mabuku anu, mukhoza kugwiritsa ntchito mphamvu zawo pogwiritsa ntchito mafunso a SQL JOIN kuphatikiza mfundo kuchokera pa matebulo angapo. Mtundu wowonjezeka kwambiri wojowina ndi SQL INNER JOIN, kapena kuphweka kosavuta. Mtumiki woterewu amabwezeretsa zolemba zonse zomwe zimakwaniritsa zojambulidwa kuchokera ku matebulo angapo. Mwachitsanzo, ichi CHIMENE chidzabwezeretsa Student_Name, Teacher_Name, ndi Course komwe makiyi akunja mwa Ophunzira akuphatikizira chofunikira kwambiri mu tebulo la aphunzitsi:
SANKANI Ophunzira.Student_Name, Aphunzitsi.Teacher_Name, Teachers.Course
Kuchokera Ophunzira
INNER JOIN Aphunzitsi
PA Ophunzira.Teacher_FK = Aphunzitsi.InstructorID;
Mawu awa akupereka tebulo chinachake chonga ichi:
Gome lobwezeretsedwa kuchokera ku SQL Join Statement
Student_NameTeacher_NameCourseLowell SmithJohn DoeEnglishBrian ShortJohn DoeEnglishCorky MendezJane SchmoeMathMonica JonesJohn DoeEnglish