Cov txheej txheem:
Video: Kuv yuav nrhiav tau cov kev txwv txawv teb chaws li cas hauv SQL Server?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Nov yog txoj hauv kev zoo tshaj plaws kom paub Foreign Key Kev sib raug zoo hauv txhua qhov Database. Hauv SQL Server Management Studio koj tuaj yeem nyem rau ntawm lub rooj hauv cov khoom tshawb nrhiav thiab xaiv "View Dependencies". Qhov no yuav ua rau koj muaj qhov pib zoo. Nws qhia cov rooj, saib, thiab cov txheej txheem uas hais txog lub rooj.
Ib yam li ntawd, nws tau nug, dab tsi yog tswj hwm txawv teb chaws tseem ceeb hauv SQL?
Txawv Teb Chaws Tseem Ceeb . A txawv teb chaws key (FK) yog ib kem lossis ua ke ntawm kab uas siv los tsim thiab yuam ib qho kev sib txuas ntawm cov ntaub ntawv hauv ob lub rooj los tswj cov ntaub ntawv uas tuaj yeem khaws cia rau hauv lub txawv teb chaws key rooj.
Tsis tas li ntawd, cov yuam sij txawv teb chaws qhia txog teeb meem dab tsi? Nov yog qee qhov teeb meem tseem ceeb txawv teb chaws.
- Dangling txawv teb chaws yuam sij. Tus yuam sij txawv teb chaws taw qhia rau tus yuam sij tseem ceeb uas tsis nyob ntawd.
- Xa mus rau tus yuam sij tshwj xeeb uas tsis yog tus yuam sij tseem ceeb. Tsis muaj txiaj ntsig rau qhov no.
- Kev sib txuas tsis raws cai ntawm cov rooj.
- Hom ntaub ntawv tsis sib haum.
- Overloaded txawv teb chaws yuam sij.
Ua raws li qhov no, kuv yuav nrhiav tau tus yuam sij txawv teb chaws hauv lub rooj li cas?
pom txawv teb chaws key kev sib raug zoo ntawm a rooj : Xaiv TABLE_NAME, COLUMN_NAME, CONSTRAINT_NAME, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME NTAWM INFORMATION_SCHEMA. KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_SCHEMA = 'db_name' THIAB REFERENCED_TABLE_NAME = 'table_name';
Kuv yuav ua li cas ntxiv qhov tseem ceeb txawv teb chaws hauv SQL Server Management Studio?
Siv SQL Server Management Studio
- Hauv Object Explorer, right-click lub rooj uas yuav nyob rau sab nraud-qhov tseem ceeb ntawm kev sib raug zoo thiab nyem Tsim.
- Los ntawm Table Designer ntawv qhia zaub mov, nyem Relationships.
- Nyob rau hauv lub Foreign-key Relationships dialog box, nyem Ntxiv.
- Nyem qhov kev sib raug zoo nyob rau hauv cov npe Xaiv Kev Sib Raug Zoo.
Pom zoo:
Yuav ua li cas los tsim thawj qhov tseem ceeb txawv teb chaws kev sib raug zoo hauv SQL Server?
Siv SQL Server Management Studio Hauv Object Explorer, right-click the table that will be on the Foreign-key side of the relationship and click Design. Los ntawm Table Designer ntawv qhia zaub mov, nyem Relationships. Nyob rau hauv lub Foreign-key Relationships dialog box, nyem Ntxiv. Nyem qhov kev sib raug zoo nyob rau hauv cov npe Xaiv Kev Sib Raug Zoo
Kuv tuaj yeem nrhiav tus yuam sij txawv teb chaws ntawm lub rooj hauv MySQL li cas?
Txhawm rau pom kev sib raug zoo txawv teb chaws ntawm lub rooj: SELECT TABLE_NAME, COLUMN_NAME, CONSTRAINT_NAME, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME NTAWM INFORMATION_SCHEMA. KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_SCHEMA = 'db_name' THIAB REFERENCED_TABLE_NAME = 'table_name';
Yuav ua li cas thiaj nrhiav tau kuv cov keeb kwm kev tshawb nrhiav hauv Google?
Saib thiab tshem tawm kev tshawb nrhiav keeb kwm hauv GoogleChrome Mus saib lub vev xaib keeb kwm hauv Google Chrome, nyem qhib cov ntawv qhia zaub mov? ntawm sab xis saum toj ntawm nws lub qhov rais thiab xaivHistory, tom qab ntawd nyem Keeb Kwm thib ob
Ib tus yuam sij txawv teb chaws puas tuaj yeem siv lwm tus yuam sij txawv teb chaws?
1 Teb. Tus yuam sij txawv teb chaws tuaj yeem siv txhua qhov chaw uas txhais tau tias nws txawv. Yog hais tias qhov tshwj xeeb teb yog nws tus kheej txhais tau tias yog tus yuam sij txawv teb chaws, nws tsis txawv. Yog tias nws yog thaj chaw tshwj xeeb, nws kuj tuaj yeem yog lub hom phiaj ntawm lwm FK
Dab tsi yog qhov kev txwv kev ncaj ncees piav qhia txog kev ncaj ncees lossis kev txwv txawv teb chaws?
Kev lees paub ncaj ncees xav kom tus yuam sij txawv teb chaws yuav tsum muaj tus yuam sij tseem ceeb sib xws lossis nws yuav tsum yog null. Qhov kev txwv no tau teev tseg ntawm ob lub rooj (niam txiv thiab menyuam); nws tuav cov ntawv xov xwm ntawm kab hauv cov rooj no. Nws txhais tau hais tias kev siv los ntawm kab hauv ib lub rooj mus rau lwm lub rooj yuav tsum siv tau