Kutsvaga mazano pakushandisa Mutauro Wemagariro Akarongwa ? Iyi Databases SQL FAQ inopa mhinduro dzemibvunzo inowanzobvunzwa pamusoro peSQL uye ma database. Iva nechokwadi chekutevera zvinyorwa zve "More Info" pamugumo wemubvunzo mumwe nomumwe kuti uwane tsanangudzo dzakawanda uye zvidzidzo!
01 yegumi
Ndingawana sei deta kubva kune database pakushandisa SQL?
Mutemo WOKUTEZA ndiyo mutemo unowanzoshandiswa muSQL. Iyo inobvumira vashandisi vepa database kuti vapezve ruzivo rwakananga rwavanoda kubva kune database yekushanda. Zvimwe »
02 yegumi
Ndinogadzira sei dhesi tsvaga kana tafura itsva ye database?
SQL inopa CREATE DATABASE uye CREATE TABLE mirairo kuti uwedzere zvinyorwa zvitsva nematafura, zvakananga kune database yako. Iyi mirairo inopa syntax yakanyatsoshandurudza inokubvumira kuti ugadzire matafura uye zvinyorwa zvinosangana nezvinodiwa zvebhizimisi rako. Zvimwe »
03 wegumi
Ndingawedzera sei dhidha kune database?
Mutemo INSERT muSQL unoshandiswa kuwedzera zvinyorwa kune tafura iripo.
04 yegumi
Ndinobvisa sei zvimwe kana tafura ye database?
Kazhinji, zvinova zvakakosha kubvisa ruzivo rusina kusimba kubva kune dhesi rekudanana. Nenzira yekuti, Yakagadziriswa Mutauro Mutauro inopa murairo weDLETE unogona kushandiswa unogona kushandiswa kubvisa zvimwe kana kuti zveruzivo rwakachengetwa mukati metafura. Zvimwe »
05 of 10
Chii chinonzi NULL kukosha?
NULL ndiyo kukosha kunoshandiswa kureva chidimbu chisingazivikanwi che data. Databases inobata NULL maitiro nenzira inokosha, zvichienderana nerudzi rwekushandiswa iyo inoshandiswa mukati. Apo nULL nhamba inowanzoonekwa seanoshandisa kuA AND operation, kukosha kwekushanda kuri FALSE kana imwe shanduro iri FALSE (hapana nzira iyo inogona kunge iCHOKWADI neine FALSE operand). Kune rumwe rutivi, chigumisiro chacho ndecheNULL (hachizivikanwe) kana mumwewo operand ari TRUE kana NULL (nokuti hatigone kuudza kuti mugumisiro wacho ungave chii.) Zvimwe »
06 of 10
Ndingaita sei kuti ndibatanidze nhamba kubva kune mabheji akawanda ema database?
SQL inobatanidza zvinyorwa zvinokubvumira kuti uyananise data kubva kumatafura maviri kana akawanda mumigumisiro yemhinduro yako. Dzidza kuti ungashandisa sei kesayenzi iyi ine simba kuti uwane hurukuro dzemibvunzo yako ye database.
07 pa10
Ndinokwanisa here kubatanidza tafura?
Ehe! Iwe unogona kushandisa kuzvibatanidza kuti uite nyore nested SQL mibvunzo apo mukati nekunze mibvunzo inodzokorora tafura imwechete. Izvi zvinobatana zvinokubvumira kuti uwane zvinyorwa zvakafanana kubva patafura imwe chete.
08 yegumi
Ndingaita sei muchidimbu deta iri mune tafura ye database?
SQL inopa hutano hwebasa kuti ibatsire nekupfupisa kwemabhuku akawanda e data. Basa reSUM rinoshandiswa mukati memutsara weCHIKAMU uye rinodzorera huwandu hwehuwandu hwehutano. Basa reAVG rinoshanda nenzira imwecheteyo kupa huwandu hwemasvomhu wehutano hwehutsika. SQL inopa COUNT basa kuti inotora nhamba yezvinyorwa zviri patafura inosangana nezvinodiwa. Iko MAX () basa rinodzorera kukosha kukuru pane imwe nhepfenyuro ye data apo MIN () basa rinodzoka kukosha kuduku.
09 yegumi
Ndingaita sei kuti ndigadzire zvinyorwa zvinyorwa?
Iwe unogona kushandisa zvinyorwa zveSQL zvinyorwa kuti uwane deta kubva kune d database asi izvi kazhinji hazvipi kupa huchenjeri hwakakwana kuti uwane zvido zvebhizimisi. SQL inopawo iwe nekwanisi yekugadzirisa mhinduro dzemhinduro zvichienderana nemafungiro emasero-mutsara kuitira kuti ushandise maitiro akawandisa uchishandisa GROUP BY clause. Zvimwe »
10 pa10
Ndingaita sei kuti ndikwanise kuwana deta iri mukati me database yeSQL?
SQL databases inopa vatungamiri vane basa-based access access system. Muchirongwa ichi, vatungamiri vanogadzira vashandisi vashandisi kune mumwe munhu wekushandisa database uye vozopa iyo user kune rimwe kana kupfuura mamwe mabasa eDDC anotsanangura nzira iyo munhu anobvumirwa kusangana nayo nedhesi. Pakupedzisira, mutungamiri anopa zvibvumirano zvakananga kune basa rinobvumira nhengo kuti dziite zviito zvinoda. Vashandi vanorambidzwa zvachose chero ruzivo rwavasina kunyatsobvumirwa. Zvimwe »