Chii mashoko? date mhando

Data - siyana mhando mashoko, systematized nevamwe parameters vachishandisa chimiro. Chii mashoko? Conventionally, ichi ndicho zvose zvinogona kuverengwa, uye kuti ipe nyaya, chipo muchimiro yakananga kutevedzana kana kuisa pamusoro Masvomhu kana Numeric okuti. Ndizvo zvose mashoko imwe nyaya nharaunda, izvo zvinogona kuiswa mune muenzaniso kana chizvaro.

kunyoresa

Yakabvuma anopa zvinhu mashoko mhando pachishandiswa maitiro avo tsika (semantics) uye kushanda kuti zvingaonekwa amakavaitira. Yainyanya kushandiswa kusanganiswa data, mari, hunhu, nguva uye musi.

Base: tsananguro uye nhoroondo

Database (db) - chine mashoko wakarongwa kuti Zvakanyanya Kunaka Panguva Yepamuviri nekuita kuwana nokukurumidza kuwana kwavari. Nzira iyi inobvumira kuti anoishandisa wokushanda makuru vhoriyamu mashoko pfuma, achipedza zvishoma nguva uye kushanda nesimba. Base - chinhu ari dzichichinja pawaiva panyaya akapinda mashoko. Chinonyanya kukosha anobatsirwei hwaro yokuti kana kushanda mashoko hatina kubvunza mubvunzo, chii data, uye chii kuti vanofanira kupiwa? All zviwanikwa ruzivo, akasuma ari kombiyuta, kwaita richiparadzirwa uye systematized ari Database. The chidzoke inogona kunzi 1955, kana takadzidza ironge mashoko ane programmable womuenzaniso faira uye kuzvichengeta pamusoro punchi nemakadhi.

Mhando Databases vavo mabasa

Databases vari centralized uye kuparadzirwa. The centralized Database ndiyo imwe sangano chimiro, kuwana izvo zvawo chero kombiyuta. Vakagovera Database rinoumbwa zvakasiyana zvikamu zvinochengeterwa pamusoro siyana michina pamusoro pemambure. ruzivo urwu pamwe rinokosha kudzora hurongwa.

garo unogonawo siyana nokuda nzvimbo, uye vanogona kuva yomunharaunda kana networked. Sezvo mashoko okuchengetera kushandisa ndangariro zvokunze (zvakaoma dhisiki), kana Manyiminya ndangariro discs Server.

Chero date akavhiyiwa vari kunze kuburikidza kuzvidzora enyika - panorongwa. Ivo vanoita anotevera:

• kusika munhu Database;
• gutsikana;
• chengetedzo;
• kuwana kuchengeteka uye mashoko voga;
• date rwokufamba kudyidzana kwavo nezvimwe zvirongwa;
• kugadzirisa;
• kunzvera;
• yokupedzisira paumbwe dzekukurira zvinokumbirwa.

Yokudzidza mudzimu upi kudzora mamiriro anogona kumiririrwa sezvinotevera: nokuumba Database itsva - Data kupinda uye fora - kubudiswa mashoko ari Database (ndiro data, mashoko kuti aripo pangoro, sezvo ivo dzikarongwa) - outputs.

The date mamiriro tafura

Kuti vaise mashoko ari Database tafura mashoko akashandiswa. Chimiro yakadaro inodiwa kuti kuona Kero Data iri Database, zviri vanowanika nokuda mharadzano pakati pemitsara uye mbiru zviri patafura. The Database mamiriro iri kutaurwa minda (mbiru), uye zviri - vakanyoresa (misara).

Chii mashoko? Ko variables kuti inogona kubviswa kuchiiswa mu zvimwe minda. Fields vakasikwa ne mamwe mashoko: Musi uye nguva, integers, mari inokwana, zviratidzo. munda mumwe nomumwe ane pachake ehupfumi aro kuvimba mhando chiyamuro data, kushanda kuti anogona kuitwa navo, uye uwandu chiyamuro vatambi. Field unogona kutaridzwa zita uye siginicha, urefu, uye zvimwe zvinhu. Nemhaka yazvino Database basa rikurumidze ruzivo rava sezvo nokukurumidza uye nyore, uye zvemagetsi izvo zviri kuita basa iri, wakawana chiine chitarisiko uye kuwanikwa nomumwe kudzora hurongwa.

Tinovimba mashoko rakapiwa munyaya kuchatibatsira.