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MySQLYiziphi izinhlobo zedatha ezisekelwayo?MySQLImininingwane yezinhlobo zedatha ku
Izinhlobo zedatha ye-MySQL
Izinhlobo zezinkambu zedatha ezichazwe ku-MySQL zibaluleke kakhulu ekusetshenzisweni kahle kwesizindalwazi sakho.
I-MySQL isekela izinhlobo ezihlukahlukene, ezingahlukaniswa cishe zibe izigaba ezintathu: izinhlobo zezinombolo, idethi/isikhathi kanye neyunithi yezinhlamvu (uhlamvu).
Uhlobo lwezinombolo
MySQL databaseZonke izinhlobo zedatha yezinombolo ze-SQL ezijwayelekile ziyasekelwa.
Lezi zinhlobo zihlanganisa izinhlobo zedatha yezinombolo eziqinile (INTEGER, SMALLINT, DECIMAL, ne-NUMERIC), kanye nezinhlobo zedatha yezinombolo (FLOAT, REAL, ne-DOUBLE PRECISION).
Igama elingukhiye elithi INT lifana negama elithi INTEGER futhi igama elingukhiye elithi DEC liyimcondvofana yelithi DECIMAL.
Uhlobo lwedatha ye-BIT luphethe amanani enkambu encane futhi lusekela amathebula e-MyISAM, MEMORY, InnoDB, kanye ne-BDB.
Njengesandiso sezinga le-SQL, i-MySQL iphinde isekele izinhlobo zezinombolo ezithi TINYINT, MEDIUMINT, kanye ne-BIGINT.Ithebula elingezansi libonisa isitoreji nobubanzi obudingekayo ohlotsheni ngalunye lwenombolo.
| Thayipha | usayizi | ububanzi (isayiniwe) | ububanzi (akusayiniwe) | Sebenzisa |
|---|---|---|---|---|
| I-TINYINT | 1 ibhayithi | (-128, 127) | (0, 255) | inombolo encane |
| SMALLINT | 2 ibhayithi | (-32 768, 32 767) | (0, 65 535) | inani lenombolo enkulu |
| MEDIUMINT | 3 ibhayithi | (-8 388 608, 8 388 607) | (0, 16 777 215) | inani lenombolo enkulu |
| I-INT noma i-INTEGER | 4 ibhayithi | (-2 147 483 648, 2 147 483 647) | (0, 4 294 967 295) | inani lenombolo enkulu |
| OKUKHULU | 8 ibhayithi | (-9 233 372 036 854 775 808, 9 223 372 036 854 775 807) | (0, 18 446 744 073 709 551 615) | inani lenombolo enkulu kakhulu |
| ISIPHULA | 4 ibhayithi | (-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) | ukunemba okukodwa inani lephoyinti elintantayo |
| DOUBLE | 8 ibhayithi | (-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. | 0, (2.225 073 858 507 201 4 E-308, 1.797 693 134 862 315 7 E+308) | ukunemba kabili inani lephoyinti elintantayo |
| ISINQUMO | Ku-DECIMAL(M,D), uma i-M>D, ingu-M+2 enye ingu-D+2 | kuncike kumanani we-M no-D | kuncike kumanani we-M no-D | inani ledesimali |
usuku nohlobo lwesikhathi
Izinhlobo zedethi nesikhathi ezimele amanani esikhathi ithi DATETIME, DATE, TIMESTAMP, TIME, kanye noYEAR.
Isikhathi ngasinye sinobubanzi bamanani avumelekile kanye nenani elithi "ziro", elisetshenziswa lapho kucaciswa inani elingavumelekile i-MySQL engakwazi ukulimelela.
Uhlobo lwe-TIMESTAMP lunesici sobunikazi sokubuyekeza ngokuzenzakalela esizochazwa kamuva.
| Thayipha | usayizi (ibhayithi) | ububanzi | Ifomethi | Sebenzisa |
|---|---|---|---|---|
| DATE | 3 | 1000-01-01/9999-12-31 | YYYY-MM-DD | inani ledethi |
| ISIKHATHI | 3 | ‘-838:59:59'/'838:59:59' | HH: MM: SS | inani lesikhathi noma ubude besikhathi |
| UNYAKA | 1 | 1901/2155 | YYYY | inani lonyaka |
| ISIKHATHI SESIKHATHI | 8 | 1000-01-01 00:00:00/9999-12-31 23:59:59 | I-YYYY-MM-DD HH: MM: SS | Amanani ahlanganisiwe edethi nesikhathi |
| ISIKHATHI SESIKHATHI | 4 | 1970-01-01 00:00:00/2037 年某时 | YYYYMMDDHMMSS | amanani edethi nesikhathi ahlanganisiwe, isitembu sesikhathi |
Uhlobo lwentambo
Izinhlobo zezintambo zibhekisela ku-CHAR, VARCHAR, BINARY, VARBINARY, BLOB, TEXT, ENUM, kanye ne-SET.Lesi sigaba sichaza ukuthi lezi zinhlobo zisebenza kanjani nokuthi zisetshenziswa kanjani emibuzweni.
| Thayipha | usayizi | Sebenzisa |
|---|---|---|
| I-TANK | 0-255 amabhayithi | iyunithi yezinhlamvu yobude obugxilile |
| I-VARCHAR | 0-65535 amabhayithi | intambo yobude obuguquguqukayo |
| I-TINYBLOB | 0-255 amabhayithi | iyunithi yezinhlamvu kanambambili efinyelela ezinhlamvini ezingama-255 |
| I-TINYTEXT | 0-255 amabhayithi | iyunithi yezinhlamvu emfushane yombhalo |
| IGAZI | 0-65 535 amabhayithi | idatha yombhalo omude ngefomu kanambambili |
| TEXT | 0-65 535 amabhayithi | idatha yombhalo omude |
| IBHLOBH ELIPHAKATHI | 0-16 777 215 amabhayithi | Idatha yombhalo wobude obumaphakathi ngendlela kanambambili |
| UMBHALO OPHAKATHI | 0-16 777 215 amabhayithi | idatha yombhalo wobude obumaphakathi |
| LONGBLOB | 0-4 294 967 295 amabhayithi | Idatha yombhalo enkulu kakhulu ngefomu kanambambili |
| LONGTEXT | 0-4 294 967 295 amabhayithi | idatha yombhalo enkulu kakhulu |
Izinhlobo ze-CHAR ne-VARCHAR ziyefana, kodwa zigcinwa futhi zibuyiswe ngokuhlukile.Zibuye zihluke ngobude bazo obukhulu kanye nokuthi izikhala zokulandela ziyagcinwa yini.Akukho ukuguqulwa kwecala okwenziwa ngesikhathi sokugcinwa noma ukubuyiswa.
Izigaba ezingu-BINARY kanye ne-VARBINARY zifana ne-CHAR ne-VARCHAR, ngaphandle kokuthi aqukethe iyunithi yezinhlamvu kanambambili esikhundleni seyunithi yezinhlamvu ezingezona kanambambili.Okusho ukuthi, aqukethe iyunithi yezinhlamvu ze-byte esikhundleni sezinhlamvu zezinhlamvu.Lokhu kusho ukuthi abanalo isethi yezinhlamvu futhi bahlele futhi baqhathanise ngokusekelwe kumanani ezinombolo zamabhayithi yenani lekholomu.
I-BLOB into enkulu kanambambili engabamba inani elihlukile ledatha.Kunezinhlobo ezi-4 ze-BLOB: i-TINYBLOB, i-BLOB, i-MEDIUMBLOB ne-LONGBLOB.Zivele zihluke ngobude obukhulu bevelu ezingabamba.
Kunezinhlobo ezingu-4 ZOMBHALO: TINYTEXT, TEXT, MEDIUMTEXT kanye ne-LONGTEXT.Lezi zihambisana nezinhlobo ezingu-4 ze-BLOB, ezinobude obufanayo obuphezulu nezidingo zokulondoloza.
I-Hope Chen Weiliang Blog ( https://www.chenweiliang.com/ ) okwabiwe "Iziphi izinhlobo zedatha ezisekelwa i-MySQL? Incazelo Eningiliziwe Yezinhlobo Zedatha ku-MySQL" ukukusiza.
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