Zvakanakira Kushandisa Zvipingamupinyi Zvisingadikanwi Pamusoro Pechikonzero Chinokosha Chokutanga
Nokugadzira UNIQUE constraint, SQL Server vatungamiri vanotsanangura kuti imwe koromo ingasave ine zvinyorwa zvinokosha. Paunenge uchitanga mutsva weUNIQUE constraint, SQL Server inotarisa iyo koromo iri mubvunzo kuti ione kana ine chero ipi zvayo yemaitiro. Kana tafura yacho ine zvinyorwa zvekare zvisati zvavapo, mutemo wezvisikwa zvekusika unokundikana. Saizvozvowo, kana iwe uine zvisizvo zvinotarisirwa paIndaneti, kuedza kuwedzera kana kushandura dhamusi inogona kuita kuti zvidimbu zvivepo zvakare zvinokundikana.
Sei Uchifanira Kushandisa Zvinopesana NeIQUE?
CHIMWE CHINHU CHINOKOSHA uye chinonyanya kukosha zvose zvinoita kuti zvive zvakakwana, asi pane dzimwe nguva apo chibvumirano che UNIQUE ndicho chisarudzo chakanaka.
- Shandisa zvinomirira UNIQUE apo unoda zvipingamupinyi zvakawanda kune tafura. Iwe unogona chete kuisa kiyi imwe yekutanga patafura.
- Shandisa zvinomirira UNIQUE apo imwe column inobvumira zvisizvo zvisingaiti. Zvinyorwa zvinyanya kukosha zvingangowanikwa kune zvinyorwa zvisingabvumi zvisikwa zvisingabatsiri.
Kugadzira chisungo cheUNIQUE
Kune nzira dzakawanda iwe unogona kugadzira CHINHU chakashata muSQL Server. Kana iwe uchida kushandisa Transact-SQL kuti uwedzere zvisizvo zveUNIQUE pane tafura iripo, unogona kushandisa izwi re ALTER TABLE, sezvinoratidzwa pasi apa:
ALTER TABLE ADDZA CONSTRAINT UNIQUE ()Kana iwe uchida kushamwaridzana neSQL Server uchishandisa GUI zvishandiso, unogonawo kuvaka UNIQUE constraint uchishandisa SQL Server Management Studio . Heino nzira:
- Vhura SQL Server Management Studio .
- Wedzera Tafura yefaira ye database uko iwe unoda kuumba chinetso.
- Tsva-keta patafura apo iwe unoda kuwedzera dambudziko uye chengeta Chigadziro .
- Muchirongwa Chekugadzirisa menyu, chengetai Nhamba / Mazano .
- Mune Indexes / Keys dialog box, bhura Add .
- Sarudza Chinokosha Chakasiyana muRudzi rusika-pasi.
Zvinokonzerwa NEIQUE zvinotsanangurwa neAIQUE Indexes
Pakave nekuvhiringidzika pamusoro pemusiyano pakati peUNIQUE constraint uye index UNIQUE. Paunenge uchigona kushandisa shanduro dzakasiyana-siyana dzeTransact-SQL kuti uzvigadzire (ALTER TABLE ... BATA CONSTRAINT nokuda kwezvimwe zvinetso uye CREATE UNIQUE INDEX ye indexed), vane zvimwe zvakafanana, kune zvizhinji. Ichokwadi, apo iwe unogadzira CHINHU chakasimbiswa, inonyanya kusimbisa index UNIQUE patafura. Zvakakosha kucherechedza, zvisinei, kuti kune kusiyana kwakasiyana:
- Paunenge uumba chinyorwa, iwe unogona kuwedzera mamwe mazano pane murairo wekusika.
- Mutsara unenge uri pasi peNGOI zvinogona kushandiswa sechinhu chekunze .