Cov txheej txheem:

Dab tsi yog cov txiaj ntsig tseem ceeb ntawm kev siv phau ntawv txhais lus cov ntaub ntawv?
Dab tsi yog cov txiaj ntsig tseem ceeb ntawm kev siv phau ntawv txhais lus cov ntaub ntawv?

Video: Dab tsi yog cov txiaj ntsig tseem ceeb ntawm kev siv phau ntawv txhais lus cov ntaub ntawv?

Video: Dab tsi yog cov txiaj ntsig tseem ceeb ntawm kev siv phau ntawv txhais lus cov ntaub ntawv?
Video: Tshuaj theem vim li cas thiaj tau nqi ?/ Siv kho mob dab tsi?/paris polyphylla use for? 2024, Kaum ib hlis
Anonim

Ib phau ntawv txhais lus tsim kho cov ntaub ntawv tuaj yeem muab cov koom haum thiab kev lag luam ntau yam txiaj ntsig, suav nrog:

  • Txhim kho cov ntaub ntawv zoo.
  • Txhim kho kev ntseeg siab hauv cov ntaub ntawv kev ncaj ncees.
  • Txhim kho cov ntaub ntawv thiab kev tswj xyuas.
  • Txo cov ntaub ntawv redundancy.
  • Rov siv dua cov ntaub ntawv .
  • Kev sib raug zoo hauv cov ntaub ntawv siv.
  • Yooj yim dua cov ntaub ntawv tsom xam.
  • Txhim kho kev txiav txim siab raws li qhov zoo dua cov ntaub ntawv .

Cov lus nug tseem yog, puas yog qhov txiaj ntsig ntawm phau ntawv txhais lus cov ntaub ntawv?

Muaj ntau qhov zoo ntawm kev siv Cov ntaub ntawv phau ntawv txhais lus hauv computer system tsom xam thiab tsim. Qhov zoo yog: sib xws, clarity; reusability; kev ua tiav; nce kev sib koom thiab kev koom ua ke; thiab yooj yim ntawm kev siv rau tus tsim tawm.

Qhov thib ob, kev siv cov ntaub ntawv txhais lus hauv DBMS yog dab tsi? A cov ntaub ntawv phau ntawv txhais lus yog ib cov ntaub ntawv los yog ib txheej ntawm cov ntaub ntawv uas muaj ib tug database metadata. Cov cov ntaub ntawv phau ntawv txhais lus muaj cov ntaub ntawv hais txog lwm yam khoom hauv database, xws li cov ntaub ntawv kev ua tswv cuab, cov ntaub ntawv kev sib raug zoo rau lwm yam khoom, thiab lwm yam cov ntaub ntawv . Cov cov ntaub ntawv phau ntawv txhais lus yog ib qho tseem ceeb ntawm cov ntaub ntawv sib raug zoo.

Ib yam li ntawd, lub hom phiaj ntawm cov ntaub ntawv txhais lus yog dab tsi?

Cov ntaub ntawv phau ntawv txhais lus yog siv los muab cov ncauj lus kom ntxaws txog cov ntsiab lus ntawm cov ntaub ntawv lossis cov ntaub ntawv, xws li cov npe ntawm cov ntsuas ntsuas, lawv cov ntaub ntawv hom lossis hom, thiab cov lus piav qhia. A cov ntaub ntawv phau ntawv txhais lus muab cov lus qhia luv luv rau kev nkag siab thiab siv cov cov ntaub ntawv.

Tus piv txwv ntawm phau ntawv txhais lus yog dab tsi?

19.11 Cov ntaub ntawv phau ntawv txhais lus A cov ntaub ntawv phau ntawv txhais lus yog qhov chaw khaws cia hauv nruab nrab ntawm metadata. Metadata yog cov ntaub ntawv txog cov ntaub ntawv . Ib txhia piv txwv ntawm yam uas yuav muaj nyob rau hauv ib lub koom haum cov ntaub ntawv phau ntawv txhais lus suav nrog: Cov cov ntaub ntawv hom, e.g., integer, tiag, tus cwj pwm, thiab cov duab ntawm txhua qhov chaw hauv lub koom haum cov ntaub ntawv.

Pom zoo: