The mitundu ikuluikulu ya MySQL deta

Kwa amene sakudziwa chimene MySQL, kukudziwitsani kuti ili ndi dongosolo kwambiri kuti amalola kuti kusamalira yambiri deta. Ndi ufulu ndi kupezeka kwa owerenga pa zikhalidwe za chilolezo ambiri. Kumayambiriro kwa kompyuta luso "warehoused" zambiri mu osiyana owona, ndiyeno anachotsa kwa iwo ngati kuli kofunika. Lerolino, kachitidwe si nthawi zonse wogwira mtima, chifukwa zimatenga nthawi yambiri ndiponso khama. MySQL pulogalamu amalola inu kuthetsa deta ndi kuchita ntchito pa magulu deta kudzera mwa yaying'ono kwambiri lamulo code.

Kuti Nawonso achichepere ndi ntchito bwino, pali lingaliro mu MySQL deta mtundu. Total kuzindikiridwa zingapo zimene mungachite izi:

- var (n) kapena VARCHAR (n) - chizindikiro, kumene N - chiwerengero cha mabayiti amene angagwiritsidwe ntchito (VARCHAR masitolo zosaposa 255 otchulidwa);

- deta mitundu chingwe MySQL, kuphatikizapo akamagwiritsa zotsatirazi: LEMBA (n) - kumene N kungakhale kwa 65.535, TINITEXT (n) - kumene N angakhale ndi phindu mpaka 255, MEDIUMTEXT (n) ndi N 16 777 215 ndipo LONGTEXT ( n) ndi variable N, amene angafikire 4294967295 (kuchokera VARCHAR variable LEMBA yodziwika kwa LEMBA (n) chakumapeto kwake koyamba N otchulidwa);

- VARBINARY kapena bayinare - kusunga zithunzi malamulo bayinare ;

- kusungiramo zinthu bayinare lalikulu ndi tcheru mitundu khalidwe deta ntchito MySQL BLOB (n), amene ali gawo lomwelo ndi "mtima" monga LEMBA (TINY-, MEDIUM-, LONGBLOB) ; Mwachitsanzo, MEDIUMBLOB (n) ali gawo N wofanana 16.777.215;

- Data mitundu patsikuli ndi nthawi, kuphatikizapo: DATE - tsiku mu mtundu chaka ndi umodzi tsiku, ndi TIME - nthawi mu mtundu ola mphindi wachiwiri, chaka - zaka kuchokera 1901 mpaka 2155 ndi chaka 0000, ndi DATETIME - Chili DATE ndi TIME (lomaliza mtundu deta chaonetsedwera mu mtundu chaka ndi umodzi tsiku maola mphindi wachiwiri); palinso mitundu ya deta MySQL mtundu wa TIMESTAMP, zomwe zimathandiza kuti Nawonso achichepere a zaka kuyambira mu 1970 mpaka 2037 (izi chifukwa cha maganizo a dongosolo ndiAmene kuti MySQL kwathunthu lotha ndi 2037);

- M'ndandanda, imene ake zikuchokera Amasangalala inteja deta mitundu, kuphatikizapo - Int - inteja pafupifupi 2.1 biliyoni kwa $ 2.1 biliyoni opanda, TINYINT - .. A chiwerengero 128 kwa 255, kapena kuchokera -127 0, SMALINT - 768 kwa 32 - 32 767, BIGINT - 9 x 10 -9 kuti chakhumi ndi chisanu ndi chitatu digiri x 10 digiri ku chakhumi ndi chisanu ndi chitatu cha, MEDIUMINT - .. kuchokera miliyoni 8,388 miliyoni -8.388 (kupatula mu mtundu makamaka deta anapereka chiwerengero zikuluzikulu pazipita akonzedwa mtengo, adzakhululukidwa truncated ndi mfundo zomveka).

Palinso mitundu ya manambala fractional - tiwolokere - ndi yoyandama mfundo chiwerengero, pawiri ndi ENIENI - chiwerengero awiri a akuyandama mfundo osalimba, M'ndandanda ndi DECIMAL - manambala fractional zasungidwa ngati zingwe. mapulogalamu The kwenikweni ntchito zimatengedwa ndi Int, amene amathandiza m'munsi ntchito mulingo woyenera liwiro.

Kugwira ntchito ndi Nawonso achichepere kudzera PHPMyAdmin chida, umene umabwera ufulu mu Denver phukusi. Ndi inu angalenge ndi Nawonso achichepere, kutchula mayina a matebulo Nawonso achichepere ndi mitundu yosiyanasiyana ya deta, mapasiwedi. Ndiye tsinde ladzala ndi mfundo, n'zotheka kulenga pempho kufufuza (SANKHANI), kusintha (KUSINTHA, Sinthani dzina, kusintha), kufufutidwa (Chotsani), kuwonjezera (kuwonjezera) Mndandanda deta ndi linanena bungwe alipo magawo kumatanthauza pa zenera. MySQL deta mitundu Pankhaniyi ayenera zidzawonjezedwa mosamala kwambiri pulogalamu sanali kupatsidwa zolakwika. Mwachitsanzo, mukhoza mwachindunji mtundu deta kwa VARCHAR, amene amalola oyamba a lemba mu Nawonso achichepere zosaposa 255 otchulidwa. Ndipo pamene kudzaza m'munsi malemba zidzakhala zoopsa kwambiri, Izi zidzapangitsa kuti chakuti MySQL "truncate" lemba kuti yaitali zovomerezeka.