Cov txheej txheem:

Yuav ua li cas koj tsim ib daim duab dependency?
Yuav ua li cas koj tsim ib daim duab dependency?

Video: Yuav ua li cas koj tsim ib daim duab dependency?

Video: Yuav ua li cas koj tsim ib daim duab dependency?
Video: Yuav ua li cas thiaj ua tau neeg zoo 2024, Kaum ib hlis
Anonim

Tsim ib daim duab Dependency

  1. Hauv BusinessEvents Studio Explorer, right-click ib qhov project peev txheej thiab xaiv Tsim Daim Duab Dependency .
  2. Qhib qhov project caij rau kev kho thiab nyem qhov Dependency Diagram () khawm nyob rau sab xis saum toj ntawm tus editor.
  3. Hauv Ib Qhov Chaw Xaiv Qhov Haujlwm daim duab , right-click ib qhov chaw thiab xaiv Tsim Daim Duab Dependency .

Tom qab ntawd, dab tsi yog daim duab kos duab database?

A kev vam khom yog ib qho kev txwv uas siv rau lossis txhais cov kev sib raug zoo ntawm cov cwj pwm. Nws tshwm sim hauv ib database thaum cov ntaub ntawv khaws cia hauv tib yam database lub rooj tshwj xeeb txiav txim siab lwm yam ntaub ntawv khaws cia hauv tib lub rooj.

Ib tug kuj yuav nug, dab tsi yog ib feem ntawm kev vam khom hauv DBMS? Ib nrab Dependency tshwm sim thaum tsis yog tus cwj pwm tseem ceeb yog ua haujlwm nyob ntawm ib feem ntawm tus neeg sib tw tus yuam sij. Daim Ntawv 2nd Normal (2NF) tshem tawm cov Ib nrab Dependency.

Tsis tas li ntawd, kev vam khom hauv SQL yog dab tsi?

A kev vam khom yog tsim thaum ib tug SQL ntawv Server object, referencing entity, refers to another SQL ntawv Server object, qhov chaw siv. Ib qho piv txwv ntawm qhov no yog kev pom ntawm lub rooj. Qhov kev pom yog qhov chaw referencing thiab lub rooj yog qhov chaw siv.

Transitive dependency nyob rau hauv DBMS yog dab tsi?

A transitive kev vam meej nyob rau hauv ib lub database yog ib qho kev sib raug zoo ntawm qhov tseem ceeb hauv tib lub rooj uas ua rau muaj kev ua haujlwm kev vam khom . Ua kom tiav cov normalization tus qauv ntawm Daim Ntawv Thib Peb (3NF), koj yuav tsum tshem tawm ib qho twg transitive kev vam meej.

Pom zoo: