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MySQLZeziphi iintlobo zedatha ezixhaswayo?MySQLIinkcukacha zeentlobo zedatha kwi
Iintlobo zedatha ye-MySQL
Iindidi zemimandla yedatha echazwe kwi-MySQL ibaluleke kakhulu ekuphuculweni kwedatha yakho.
I-MySQL ixhasa iintlobo ngeentlobo zeentlobo, ezinokuthi zahlulwe ngokuthe ngqo kwiindidi ezintathu: amanani, umhla / ixesha, kunye neentlobo zentambo (umlinganiswa).
Uhlobo lwamanani
MySQL databaseZonke iindidi zedatha zamanani zeSQL zixhaswa.
Ezi ntlobo ziquka iindidi zedatha yamanani angqongqo (INTEGER, SMALLINT, DECIMAL, kunye neNUMERIC), kunye neentlobo zedatha yamanani aqikelelwayo (FLOAT, REAL, kunye ne-DOUBLE PRECISION).
Igama elingundoqo elithi INT sisithethantonye se-INTEGER kunye negama elingundoqo elithi DEC sisithethantonye se-DECIMAL.
Uhlobo lwedatha ye-BIT ibamba amaxabiso entsimi kancinane kwaye ixhasa iMyISAM, MEMORY, InnoDB, kunye neetafile zeBDB.
Njengolwandiso kumgangatho weSQL, iMySQL ikwaxhasa iindidi ezipheleleyo TINYINT, MEDIUMINT, kunye neBIGINT.Itheyibhile engezantsi ibonisa ugcino kunye noluhlu olufunekayo kudidi ngalunye olupheleleyo.
| Chwetheza | ubungakanani | uluhlu (isayiniwe) | uluhlu (alubhalwanga) | Sebenzisa |
|---|---|---|---|---|
| I-TINYINT | Ibhayithi e-1 | (-128) | (0, 255) | ixabiso elincinci elipheleleyo |
| Intetho yesibongo, imvelaphi, ukuhambelana kwefayili SMALLIN | Ibhayithi e-2 | (-32 768, 32 767) | (0, 65 535) | ixabiso elipheleleyo elipheleleyo |
| MEDIUMINT | Ibhayithi e-3 | (-8 388 608, 8 388 607) | (0, 16 777 215) | ixabiso elipheleleyo elipheleleyo |
| INT okanye INTEGER | Ibhayithi e-4 | (-2 147 483 648, 2 147 483 647) | (0, 4 294 967 295) | ixabiso elipheleleyo elipheleleyo |
| OMKHULU | Ibhayithi e-8 | (-9 233 372 036 854 775 808, 9 223 372 036 854 775 807) | (0, 18 446 744 073 709 551 615) | ixabiso elipheleleyo elipheleleyo |
| UMKHAMBA | Ibhayithi e-4 | (-3.402 823 466 E+38, -1.175 494 351 E-38), 0, (1.175 494 351 E-38, 3.402 823 466 351 E+38) | 0, (1.175 494 351 E-38, 3.402 823 466 E+38) | ukuchaneka enye ixabiso lendawo edadayo |
| UDADA | Ibhayithi e-8 | (-1.797 693 134 862 315 7 E+308, -2.225 073 858 507 201 4 E-308), 0, (2.225 073 858 507 201 4 E-308, 1.797, 693, 134, 862, 315, 7, 308, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX, XNUMX) | 0, (2.225 073 858 507 201 4 E-308, 1.797 693 134 862 315 7 E+308) | ukuchaneka kabini ixabiso lendawo edadayo |
| ISIGQIBO | KwiDECIMAL(M,D), ukuba M>D, nguM+2 enye nguD+2 | kuxhomekeke kumaxabiso e-M kunye no-D | kuxhomekeke kumaxabiso e-M kunye no-D | ixabiso lokugqibela |
umhla kunye nodidi lwexesha
Umhla kunye neentlobo zexesha ezimele amaxabiso exesha ngu-DATETIME, DATE, TIMESTAMP, TIME, kunye noYEAR.
Udidi lwexesha ngalinye lunoluhlu lwamaxabiso asebenzayo kunye nexabiso elithi "zero", elisetyenziswa xa kuchazwa ixabiso elingasebenziyo uMySQL ongenakulimela.
Uhlobo lwe-TIMESTAMP lunobunikazi bohlaziyo oluzenzekelayo oluya kuchazwa kamva.
| Chwetheza | ubungakanani (byte) | Uluhlu | ifomathi | Sebenzisa |
|---|---|---|---|---|
| UMHLA | 3 | 1000-01-01/9999-12-31 | YYYY-MM-DD | ixabiso lomhla |
| IXESHA | 3 | ‘-838:59:59'/'838:59:59' | HH: MM: SS | ixabiso lexesha okanye ubude bexesha |
| UNYAKA | 1 | 1901/2155 | YYYY | ixabiso lonyaka |
| IXESHA LEXESHA | 8 | 1000-01-01 00:00:00/9999-12-31 23:59:59 | YYYY-MM-DD HH: MM: SS | Umhla kunye namaxabiso adibeneyo |
| IXESHA ELITSHA | 4 | 1970-01-01 00:00:00/2037 年某时 | YYYYMMDDHMMSS | umhla oxutyiweyo kunye nexesha lamaxabiso, isitampu sexesha |
Uhlobo lomtya
Iintlobo zomtya zibhekisa kwi-CHAR, VARCHAR, BINARY, VARBINARY, BLOB, TEXT, ENUM, kunye neSET.Eli candelo lichaza indlela ezi ntlobo zisebenza ngayo kunye nendlela yokuzisebenzisa kwimibuzo.
| Chwetheza | ubungakanani | Sebenzisa |
|---|---|---|
| Char kwezinye iilwimi | 0-255 bytes | umtya wobude obusisigxina |
| VARCHAR | 0-65535 bytes | umtya wobude obuguquguqukayo |
| I-TINYBLOB | 0-255 bytes | umtya wokubini ukuya kutsho kuma-255 oonobumba |
| INCWADANA YEENKCUKACHA | 0-255 bytes | umtya wokubhaliweyo omfutshane |
| IBLOBO | 0-65 535 bytes | idatha yokubhaliweyo okude kwimo yokubini |
| TEXT | 0-65 535 bytes | idatha yombhalo omde |
| IBHUBHU ELIPHAKATHI | 0-16 777 215 bytes | Idatha yombhalo wobude obuphakathi kwifom yokubini |
| ISICATSHULWA ESIPHAKATHI | 0-16 777 215 bytes | idatha yombhalo wobude obuphakathi |
| LONGBLOB | 0-4 294 967 295 bytes | Idatha enkulu kakhulu yokubhaliweyo kwifom yokubini |
| IXESHA ELIDE | 0-4 294 967 295 bytes | idatha enkulu kakhulu yokubhaliweyo |
Iintlobo ze-CHAR kunye ne-VARCHAR ziyafana, kodwa zigcinwa kwaye zifunyanwa ngokwahlukileyo.Zikwahluka ngokobude bazo obukhulu kunye nokuba iindawo zokulandela ziyagcinwa.Akukho kuguqulwa kwetyala kwenziwa ngexesha lokugcinwa okanye ukufunyanwa.
I-BINARY kunye ne-VARBINARY iiklasi ziyafana ne-CHAR kunye ne-VARCHAR, ngaphandle kokuba ziqulathe imitya yokubini endaweni yemitya engeyiyo ekabini.Oko kukuthi, ziqulathe iintambo ze-byte endaweni yemitya yoonobumba.Oku kuthetha ukuba abanaseti yabalinganiswa, kwaye ukuhlelwa kunye nothelekiso lusekwe kumaxabiso amanani ebhayithi zexabiso lekholam.
I-BLOB yinto yokubini enkulu enokuthi ibambe inani eliguqukayo ledatha.Kukho iintlobo ezi-4 ze-BLOB: TINYBLOB, BLOB, MEDIUMBLOB kunye neLONGBLOB.Ziyahluka nje kubude obuninzi bexabiso abanokulibamba.
Kukho iintlobo ezi-4 ze-TEXT: TINYTEXT, TEXT, MEDIUMTEXT kunye neLONGTEXT.Ezi zihambelana neentlobo ze-BLOB ezi-4, ezinobude obufanayo kunye neemfuno zokugcina.
Ndiyathemba Chen Weiliang Blog ( https://www.chenweiliang.com/ ) kwabelwana "Zeziphi iindidi zedatha ezixhaswa nguMySQL? Inkcazo eneenkcukacha yeeNdidi zeDatha kwiMySQL" ukukunceda.
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