Eyona eziphambili ze data I SQL

Kuba abo bangazazanga I SQL yam, ukuba sikwazise wena ukuba le nkqubo kakuhle kakhulu ukuba kukuvumela ukuba uphathe izixa ezikhulu data. It is free kwaye ziyafumaneka kubasebenzisi phezu imiqathango yelayisenisi jikelele. Ekuqaleni ubuchwepheshe computer "warehoused" ulwazi izifayile ezisecaleni, uze emva koko ndabushenxisayo kubo xa kuyimfuneko. Namhlanje, le ndlela ayisoloko kakuhle, kuba kuthatha ixesha kunye nomgudu. software I SQL yam ikuvumela ukuba ukuyisombulula le data kwaye enze imisebenzi lens data esebenzisa compact kakhulu ikhowudi umyalelo.

Ukuze ledatha ukuze isebenze kakuhle, kukho ingqiqo kwi SQL yam uhlobo data. Lilonke ichonge zeenketho:

- var (n) okanye VARCHAR (n) - umqondiso, apho n - inani le bytes ezinikeziweyo enokusetyenziswa (VARCHAR Iivenkile oonobumba hayi ngaphezulu kwe 255);

- data iintlobo umtya I SQL yam, kuqukwa neefomathi zilandelayo: TEXT (n) - apho n ungaba kuze 65.535, TINITEXT (n) - apho n inokuba nexabiso ukuya ku-255, MEDIUMTEXT (n) kunye n-16 777 215 no LONGTEXT ( n) lo n bume, owawufikelela 4294967295 (ukusuka VARCHAR TEXT bume Eboniswe ukuba TEXT (n) indexed oonobumba n kuqala);

- VARBINARY okanye okubini - ukugcina imifanekiso kwikhowudi yokubini ;

- ukugcina izinto ezinkulu yokubini ezibuthathaka ngabo basebenzisa iindidi zedata I SQL yam Blob (n), banayo nenkalo efanayo "isimaphambili", njengoko TEXT (TINY-, eliphakathi, LONGBLOB) ; umzekelo, MEDIUMBLOB (n) iye nenkalo n ilingana 16.777.215;

- iintlobo data ye umhla kunye nexesha, kubandakanywa: DATE - a umhla kwi fomati kunyaka-nyanga-umhla, ixesha - ixesha kwiyure ngomzuzu-yesibini ifomati, nonyaka - iminyaka ukususela 1901 ukuya 2155 kunye nonyaka 0000, a datetime - ihlanganisa DATE kunye TIME (uhlobo lokugqibela data eboniswe kunyaka-ngenyanga-umhla-hour-ngcaciso-yesibini format); kukho iindidi data I SQL yam yokufomatha simiswe, evumela ukuba wenze kuvimba iminyaka ukususela ngowe-1970 ukuya 2037 (oku kubangwa Kwingcingane kwinkqubo yiko ukuba SQL yam ngokupheleleyo ezavalwayo nge-2037);

- amanani, leyo kumafa yayo iintlobo elipheleleyo data, kubandakanywa - INT - elipheleleyo ukusuka malunga 2.1 billion ukuya $ 2.1 yezigidi zezigidi thabatha, TINYINT - .. A Inani ukusuka 128 ukuya 255, okanye ukusuka -127 ukuya 0, SMALINT - 32 768 ukuya - 32 767, BIGINT - ukususela 9 x 10 kumlinganiselo elinesibhozo -9 x 10 kumlinganiselo elinesibhozo, MEDIUMINT - ukususela 8,388 yezigidi ukuya -8,388 yezigidi (ukuba uhlobo oluthile data ukuseta inombolo enkulu.. ixabiso iseti eliphezulu, iya thumbanails amaxabiso esebenzayo).

Kukho kwakhona iintlobo amanani iqhezu - edadayo - yi lencopho inombolo point, KABINI kunye AMAVA - kabini inani lencopho indawo Ukuxinana, amanani kunye IDESIMALI - amanani iqhezu zigcinwe neengcingo. Zokuhlela kuqala kusetyenziswa abhabhe kunye INT, ezixhasa isiseko usebenza ngesantya kangangoko.

Ukusebenza database ngokusebenzisa isixhobo PHPMyAdmin, nto leyo eza simahla package Denver. Ngalo ungenza i solwazi, ecacisa amagama iitafile zesiseko sedata ze iintlobo ezahlukeneyo ze data, password. Ngoko ke isiseko uzaliswe iinkcukacha, unako ukwenza isicelo search (KHETHA), utshintsho (Tshintsha, ukuthiya ngokutsha, ukulungisa), ukususwa (SUSA), yongeza (yongeza) okanye yokulungisa i ekhoyo data kunye output parameters ezichazwe kwi PMFA. iindidi zedata I SQL yam kule meko kufuneka kongezwe ngenyameko kakhulu inkqubo abazange banikwe iimpazamo. Umzekelo, ungakhankanya uhlobo data ukuba VARCHAR, evumela ukungeniswa Okubhaliweyo kule database abalinganiswa hayi ngaphezulu kwe-255. Kwaye xa ugcwalisa okubhaliweyo luya kuba sezingeni elikhulu, nto leyo eya kukhokelela ekubeni i-SQL "libe ngamalungu asibhozo 'okubhaliweyo kwi ubude eyamkelekileyo.