Chimwe chinyorwa chekunze chinozarura musuo kune nyika yose yedhadha
Vashandi vekugadzira mapepa vanoita zvakanyanya kushandisa kiyi pavanokudziridza relational database. Pakati pezvakanyanya kufanana zveiyi makiyi makiyi makuru uye makeni ekune dzimwe nyika. Rimwe rekodhi rekunze kune imwe nyika inomunda mune imwe tafura inoshamwaridzana iyo inofananidzwa nechokutanga chekomba yeimwe tafura. Kuti tinzwisise kuti imwe seni yekune dzimwe nyika inoshanda sei, regai tinyatsocherechedza pfungwa yemadhorobha rekudanana.
Dzimwe Basics of Relational Databases
Muchidimbu chekudanana, deta iri kuchengetwa mumatafura ane mizere uye ma column, zvichiita kuti zvive nyore kutsvaga nekushandisa.Ipapo pane mamwe masvomhu akaoma mushure mekuda kwe database ye relational (relational algebra, yakarongwa neEF
Codd paBM muna 1970), asi iyo haisi nyaya yenyaya ino.
Nokuda kwezvinangwa (uye vasiri vetambi vemasvomhu), dheseti rezvekodzero inoisa "data" inowanikwa mumitsara nemadzamu. Kuwedzera-uye apa ndiyo inofadza-yakawanda yakawanda yakagadzirirwa kuitira kuti data iri mune rimwe tafura inogona kuwana dhimwe mune imwe tafura. Iko kukwanisa kugadzira ukama pakati pematafura ndiyo simba chaiyo yedhoropu rezvekodzero.
Kushandisa Kwenyika Kwenyika
Kazhinji matafura, kunyanya aya ari makuru, akawandisa mabhuku, ane zvigaro zvekutanga. Tables yakagadzirirwa kuwana mamwe matafura inofanirawo kuva nekona yekunze.
Kuti ushandise dhesi yeNorthwinds inowanzonzi, inowanzobva pane Product table:
| ProductID | ProductName | CategoryID | QuantityPerU | UnitPrice |
|---|---|---|---|---|
| 1 | Chai | 1 | 10 mabhokisi x 20 mabhegi | 18.00 |
| 2 | Chang | 1 | 24 - 12 oz mabhodhoro | 19.00 |
| 3 | Aniseed Syrup | 2 | 12 - 550 ml mabhodhoro | 10.00 |
| 4 | Chef Anton's Cajun Mwaka | 2 | 48 - 6 oz jars | 22.00 |
| 5 | Chef Anton's Gumbo Mix | 2 | 36 mabhokisi | 21.35 |
| 6 | Ambuya va Boysenberry Vanoparadzira | 2 | 12 - 8 oz jars | 25.00 |
| 7 | Uncle Bob's Organic Akaoma Pears | 7 | 12 - 1 lb pkgs. | 30.00 |
The ProductID column ndeyedu yekutanga yefurafura. Inopa chizivo chinoshamisa pane chimwe chigadzirwa.
Iyi tafura inewo chinyorwa chekune imwe nyika, CategoryID . Chigadzirwa chimwe nechimwe muChigadzirwa chetafura chinosangana nekupinda mukati memaDheta mapeji anotsanangura chigadzirwa ichocho.
Cherechedza izvi zvakabva kune database yeChitatu chetafura:
| CategoryID | CategoryName | Tsanangudzo |
|---|---|---|
| 1 | Zvokudya | Zvimwe zvinwiwa, mafivha, teas, doro, uye ales |
| 2 | Condiments | Mafuta akanaka uye anonaka, anodzokorora, anopararira, uye nguva |
| 3 | Confections | Desserts, candies, uye mapapiro |
| 5 | Dairy Products | Cheeses |
Nzvimbo yeClassID iyi ndiyo iyi korona yekutanga. (Haina kiyi yekunze nokuti haina chido chekuwana imwe tafura. Semuenzaniso, chibereko Chai inopiwa chirongwa che "Zvokudya", asi Aniseed Syrup iri munyaya yeCondiments.
Icho chikwata chekubatanidza chinoumba nzira dzakasiyana-siyana dzokushandisa uye kushandisa zvakare dhesiki mune dhesi rekodzero.