Ka yi tunanin wani halayen a matsayin halayyar
Wani bayanan yanar gizon yana da iko fiye da ɗigon bayanan da yake kama da shi yana da babban bincike. Haɗin bayanan haɗin gizon haɗin gicciye a cikin tebur daban-daban da kuma aiwatar da lissafin ƙididdiga akan yawancin bayanai da aka haɗa. An shirya bayanin a hanyar da za'a iya sarrafawa, samun dama, da sabuntawa.
Mene ne Halayyar?
Cibiyar ta kunshi Tables. Kowane tebur yana da ginshiƙai da layuka.
Kowace jere (da ake kira tuple) wani tsari ne wanda ya shafi wani abu ɗaya. Kowane shafi (sifa) ya ƙunshi ya bayyana halaye na layuka. Sakamakon bayanan yanar gizo shine sunan shafi da kuma abubuwan da ke cikin filayen da ke ƙarƙashinsa a cikin tebur a cikin wani bayanai.
Idan ka sayar da samfurori ka shigar da su cikin tebur tare da ginshiƙai na ProductName, Farashin, da ProductID, kowane ɓangaren sune wani halayen. A cikin kowane filin a ƙarƙashin shafukan, kun shigar da sunayen samfurori, farashin, da kuma samfur samfurori, bi da bi. Kowace shigarwa a filin shi ma wani sifa ne.
Wannan yana da mahimmanci lokacin da kake tunani game da shi, ya ba da cewa fassarar da ba ta fasaha ba game da wata siffar ita ce cewa tana bayanin halayyar ko ingancin wani abu.
Halayen Bayyana Abubuwan Taɗi
Bari muyi la'akari da bayanai da kasuwancin ke bunkasa. Yana iya haɗawa da Tables-waɗanda ake kira 'yan ƙungiyoyi ta masu zane-zanen bayanai - ga Abokan ciniki, ma'aikata, da kuma Products, da sauransu. Tebur Products yana bayyana halaye na kowanne samfurin.
Wadannan zasu iya haɗa da lambar ID, sunan samfur, ID mai amfani (amfani da maɓallin waje ), da yawa, da farashin. Kowace halayen waɗannan alamun sune alamar launi (ko mahaluži) mai suna Products.
Ka yi la'akari da wannan snippet daga database mai suna Northwinds:
| ProductID | Sunan Sunan | SupplierID | CategoryID | YawanTaɗa | UnitPrice |
|---|---|---|---|---|---|
| 1 | Chai | 1 | 1 | 10 kwalaye x 20 bags | 18.00 |
| 2 | Chang | 1 | 1 | 24 - 12 tabarbalan gas | 19.00 |
| 3 | Sugar Aniseed | 1 | 2 | 12 - 550 ml kwalabe | 10.00 |
| 4 | Chef Anton na Cajun Seasoning | 2 | 2 | 48 - 6 na kwalba | 22.00 |
| 5 | Chef Anton's Gumbo Mix | 2 | 2 | 36 kwalaye | 21.35 |
| 6 | Grandma ta Boysenberry yada | 3 | 2 | 12 - 8 oz kwalba | 25.00 |
| 7 | Uncle Bob's Organic Dried Pears | 3 | 7 | 12 - 1 lb pkgs. | 30.00 |
Sunaye sunaye sune halayen samfurin. Bayanan shigarwa a cikin sassan ginshiƙai sune halayen samfur.
Shin Hanya ne a filin?
Wasu lokuta, ana amfani da kalmar filin da sifa a cikin juna, kuma saboda mafi yawan dalilai, sun kasance daidai. Duk da haka, ana amfani da filin don amfani da tantanin halitta a cikin teburin da aka samo a kowane jere, yayin da ake amfani da sifa don bayyana halin haɓaka a halayyar hankalin.
Alal misali, a cikin tebur a sama, samfurin suna a cikin jere na biyu shi ne Chang . Wannan filin ne . Idan kuna tattaunawa game da samfurori a gaba ɗaya, ProductName shine shafi na samfurin. Wannan shi ne sifa .
Kada ku rataye akan wannan. Sau da yawa, waɗannan kalmomin biyu suna amfani da juna.
Ma'anar Bayanan
An bayyana halayen a cikin sha'anin yankin su . Wani yanki yana ƙayyade dabi'u masu iyaka da wannan alamar zata iya ƙunsar. Wannan zai iya haɗa da nau'in bayanai, tsawonsa, dabi'u, da sauran bayanai.
Alal misali, yankin don wani alamar samfurin ProductID zai iya sanya nau'in bayanan digiri. Za'a iya ƙayyade alamar da ake bukata don buƙatar wataƙƙen tsayin ko saka ko an sami izini maras kyau ko maras tabbas.