Tepu mahi hanga i roto i te SQL - Waihanga Ripanga

Mahi ki ngā pātengi raraunga e pā ana tika ki nga tepu huringa me te raraunga i roto i ratou. Otiia i mua i te tīmatanga o te mahi o te tepu, ki te waihanga. He he he mahi SQL motuhake ki te whakaaunoa tenei tukanga - "FAU TABLE".

Ko te mea tuatahi!

I mua i tatou mahi ki te tukanga o te hanga ripakaute te whakamahi i MS SQL "FAU TABLE" whakahau, he mea e tika ana ki te noho i runga i te mea e ti'a ia tatou ki te mohio i mua i te whakamahi i te mahi.

Tuatahi o te katoa, e hiahia ana koe ki te haere mai ki te ingoa o te tepu ake - me te mea ahurei whakaritea ki ētahi atu i roto i te pātengi raraunga, me te whai i te torutoru ture. Me tīmata i te ingoa ki te pukapuka (az), a ka kia e aru e tetahi pukapuka, mati, me ngā, e kore e te parau hua e te kupu rāhui. e kore e taea e te ingoa ripanga nui 18 pūāhua.

Ka tautuhia te ingoa, kia whakawhanakehia te hanganga: ki te haere mai ki te ingoa o te tīwae whakamahia ki te whakaaro i to ratou momo raraunga ake, a e āpure me whakakiia. He Kei te hoki te whakatau tonu te mara waho me mau taviri tuatahi, a hoki ka taea ki te whakawhāiti i ngā uara raraunga.

Ko te toenga o te tepu e taea e tika ngāwari motuhake e tika, na te taahiraa o te hanga i te tepu, ka taea te whakaaro ratou kahore ki te mutunga.

wetereo

Ko te hanganga o tepu, ka taea e koe puta ki tona hanganga. Hanga reira ngāwari nui, te whakamahi i SQL mahi "FAU TABLE". E titau te reira i te kaiwhakamahi ki te tautuhi i te mea whakaaro mua he ingoa tepu, me te tīwae rārangi, te tauwhāiti mō ia momo me te ingoa. Ko te wetereo, ko te rite whai:

Waihangaia he TABLE table_name
({Column_name Momoraraunga [TAUNOA faaiteraa] [column_constraint] ... | table_constraint}
[, {Column_name Momoraraunga [faaiteraa TAUNOA ] [column_constraint] ... | table_constraint}] ...)

Ko te tautohetohe whakamahia i roto i te āhuatanga hoahoa e whai ake nei:

• table_name - te tepu ingoa
• column_name - he tīwae ingoa
• momo raraunga whakamahia i roto i tenei mara - Momoraraunga
• TAUNOA - he kīanga whakamahia i roto i te taunoa tīwae.

Ko taea hoki ki te whakamahi i rua atu ngā tohenga taumahi:

• tautuhinga tīwae - colum_constraint
• tautuhinga tepu - table_constraint

I roto i a ratou, ka taea e te kaiwhakamahi whakapūtā te mahi e hiahiatia ana mo nga whāititanga tikanga o te whakakī i te tepu ranei.

Āhuatanga hanga tepu

A, no te tuhituhi te rapu ki SQL "Waihanga Ripanga" mahi, i te reira ko te tahi mau taime e tika ana ki te whakatū i ngā ture mō te whakakī i te parae. Ki te mahi i tenei, e hiahia ana koe ki te tāpiri i ngā āhuatanga huanga motuhake e tautuhi te huinga ngā o tikanga.

I roto i te tikanga ki te whakatau mehemea he pūtau ki Kia whakakahore, ka whakapūtā te ingoa me te momo o te tīwae pau rēhita tetahi o te kupu matua: i korengia (kia whakakahore uara), ranei Kāore i korengia (mara pau whakakiia).

A, no te hanga i te tepu i roto i nuinga o te wā e hiahiatia ana ki te whakakotahi ia record ki te karo ia e rua ōrite. Ki te mahi i tenei maha whakamahi tataunga raina. Na, kia rite ki te kore ki te rapu utu i te matauranga kaiwhakamahi o te take hou, e wātea ana i roto i te tepu, i roto i te mahi "FAU TABLE" he nui ki te whakarite i tētahi tīwae matua tuatahi e tuhi i te kupu matua "kī Paraimere" i muri i te mara hāngai. I roto i te nuinga o te wā, i te reira ko te tuatahi matua me i reira ko te hononga i waenganui i nga papa.

Ki te whakarite i te huti ki whakamahia te taonga matua Paraimere te he kī ke "FAUFAA FOREIGN". E tautuhi ana i te taonga mo te tīwae, koutou ia haapapu e, tenei mara pai ai i roto i te taua uara rite tetahi o te hunga e i roto i te tuatahi matua tīwae o te taua ranei i tetahi atu tepu. Ko te kupu e taea tetahi te whakarite kia raraunga.

Hei whakarato whakaū mō te tautukunga ki etahi huinga tohua he whakamāramatanga ranei, te whakamahi i te Taki huanga. Ia tikanga te hou i roto i te rārangi o ngā tohenga ki te taumahi, me te rite he whaiaro tawhā kua he Boolean kīanga. Ki reira, ka taea e koe te aukati i te rārangi o ngā uara taea, hei tauira, te whakamahi i roto i te mara o te tepu "Paora" te pukapuka "M" anake me "F".

Ētahi atu te hunga aroaro, te mahi SQL "FAU TABLE" He tonu maha huanga motuhake, engari kei te whakamahia ratou i roto i te mahi he nui iti noa.

tauira

Hei mahino kakato te mahi o te mahi, he utu whakaaro i roto i te mahi reira, me pehea te FAU TÜTOHI (SQL). Ko te tauira i raro nei hanga he ripanga aroaro i raro:

Waihanga TABLE Ritenga
(ID Char (10) matua Paraimere i korengia NOT,
Custom_name Pūāhua (20)
Custom_address Char (30)
Custom_city Pūāhua (20)
Custom_Country Char (20)
ArcDate Char (20))

Ka rite ki a koutou e taea te kite, te whakatakoto i te kore taea o uara i roto i te pūtau (i korengia) e taea te mahue, mai i te whakamahia i te reira na roto i te taunoa.