Nzira Yokuziva Nayo Dhipatimendi Rekushandisa Kushandisa Superkey

A superkey chiyeuchidzo chinogona kushandiswa kutarisa rekodhi re database

A superkey ingangodaro imwe chete kana kusanganiswa kwezvinhu zvinogona kushandiswa kunyanya kuziva rekodhi re database. Tafura inogona kuva nekubatana kwakawanda kunogadzira superkeys.

Superkey Example

Tafura ine minda , , uye , somuenzaniso, ine zvakawanda zvingaita superkeys. Zvine zvitatu zvinokwana , uye .

Zita Age SSN Phone Phone.
Robert Jones 43 123-45-6789 123
Beth Smith 43 234-56-7890 456
Robert Jones 18 345-67-8901 789

Sezvaunogona kuona, mapuranga e uye ane zvinyorwa zvizhinji nemashoko akafanana. Nepo iyo korumusi inogona kushandiswa kuwana munhu, kutambanudza foni kunogona kuchinjwa.

Aina dze Superkeys

Pakati peavo vakarongerwa mu tafura iri pamusoro, chete ndiyo chinhu chakakosha , iyo ichinyorwa chinokosha chemasikisiki anoshandisa zvishoma zvigadziro zvekunyatsoziva zvinyorwa. Zvimwe zvinyorwa zvine ruzivo rwusingadikanwi kutora marekodhi.

Iko inogonawo kutumidzwa sekiyo duku kana kuti zvishoma zvishoma nokuti ine zvishoma zvinyorwa zvinodiwa kuti zvive nekodhi rimwe rega. Pakati pemitsetse imwechete, kiyi yekutanga inogonawo kuva yakakosha uye chinhu chiduku nokuti inofanira kunge yakananga kunyora zvinyorwa, uye inofanira kunge isiripo kana iripo, ichinje.

Kana tafura yacho isina "SSN> korona uye mushandirwi anogona kuumba nhamba dzevaranda kuitira kuti awane vanhu.

Nhamba idzodzo dzevashandi dzaizotumidzwa kuti "keyrogate key key". Ichi chinokosha chinonyanya kukosha chinogonawo kushanda sechikwata.