Tsari irin na danniya database - shi ... Model, misalai

Tsari irin na danniya database - a database dangane da wata itãciya tsarin. Bisa ga ka'idar ginin da shi da ɗan kama da kwamfuta ta fayil tsarin. Muna amfani da wannan tsarin yana da amfani ko rashin amfani, wanda da za a tattauna a wannan labarin, tare da cikakken misalai.

siffofin Database

Kamar yadda aka sani, rarrabe hudu iri postoreniya database:

• Da zumunci - tabular database, inda bayanai da aka gabatar a cikin nau'i na layuka-ginshikan. Bisa wannan ka'ida, da database da ake gina a cikin "Acces", misali.
• Object-daidaitacce - suna a hankali dangantaka da PLO (da shirye-shirye a cikin abin da muke aiki tare da abubuwa), kuma wannan shi ne babban amfani, amma saboda su kananan yi, har yanzu suna da muhimmanci ƙananan fiye da a da zumunci ruwan dare.
• Hybrid - DBMS iya ƙunsar da kawai biyu na sama jinsunan.
• Matsayi - da abu na hankali na wannan labarin. Wannan database ne halin da itacen-kamar tsarin.

Mafi shahara misali da wani matsayi database ne mai samfurin halitta da IBM ( "AyBiEm"), cancantan Information Management System (fassara a matsayin "Management Information System"), da rage tsawon as IMS. A farko version of IMS zo da baya a baya, karni na ashirin, a cikin sittin da takwas shekara. Ana amfani da data ajiya da kuma kula da wannan rana.

Principles of matsayi model

The matsayi data model dogara ne a kan wadannan ka'ida:

• ga kowane kumburi daga itacen tsarin da aka sanya a cikin wani iri daya kashi.
• A kashi ne data filin sanya wa kowane filin sunan ya sa a daya line tuple.
• Wani rubutu: daya shigar da mahara fitarwa segments ga kowane labari filin.
• ga kowane tsarin kashi akwai daya da kuma kawai wuri guda a matsayi na tsarin.
• itace tsarin fara da tushen kashi.
• kowane kumburi daya kawai bawa m, amma kowanne tushen iya zama mahara zuriyarsa.

Amfani da wani matsayi data tsarin

Tsari irin na danniya database - wannan ajiya zartar wa waɗanda tsarin, wanda asali halin da itacen tsarin. Domin su a zabi irin wannan kwaikwaiyo - shi ne ma'ana.

Wani misali da wani matsayi database asali systematized digiri - wani soja, wanda aka sani ga a fayyace maki. Har ila yau, zai iya zama hadaddun sunadaran kunshi dukkan kara Saukake zuwa kasa na da matsayi barbashi. Domin da kwaikwaiyo na irin tsarin da kuma kawo su zuwa ga tsari dauke DB ba za mu decompose. Duk da haka, irin wannan halin da ake ciki shi ne ba ko da yaushe haka al'amarin.

Bugu da ƙari, akwai wani hali ga downward da fasali mai sauki tambaya fiye da guda ɗaya zuwa gaba.

Ainihin yadda ake gudanar a database, gina a kan matsayi model

A tsarin da wani matsayi database damar nasara da kuma kusan seamlessly (dangane da basira) to yin wadannan aiki (wakilta fi na asali, cikin jerin iya ko da yaushe za a mika tare da kananan tarawa):

• bincika da database da wani kashi.
• miƙa mulki na database - daga bishiya zuwa.
• mi - itace daga reshe ya reshe.
• Haka kuma, gwamnatin rikon kwarya a rassan - rabi da rabi.
• Aiki tare da rikodin: sa wani sabon da / ko halin yanzu kau, kwashe, sabon, da dai sauransu ...

A ra'ayin kowa bayanin irin tsarin

Kalmar "itace", don bayyana tsarin ake magana a kai a cikin wannan labarin ne riga nisa fiye da sau daya. Yana lokaci in gaya maka yadda ya faru. All saboda matsayi database - yana da irin wannan database, wanda yana amfani da data type "itace". Bari mu bincika abin da ya wakiltar.

Wannan kumshin type: a kowane daga cikin abubuwa (nodes) za a iya saka gaba 'yan (daya ko fiye). Yana duk farawa da guda tushen kashi. A kasa line ne cewa kowane daya daga cikin guda kamar "itace" ne a subtype, ma, "itace." Mutane da yawa, da yawa branched, kuma duk da-umurce Tsarin.

Basic iri iya zama sauki ko fili, amma da gaske shi ne ko da yaushe rikodi. Amma a cikin sauki rikodi akwai daya irin data, da kuma a cikin wani fili - cikkaken sa na su.

Tsari irin na danniya model ne peculiar da manufa na 'ya'yansa, idan kowane baya sashi ne m for daga baya. Bugu da kari, da yaro dangane da iyaye irin ne mai irin bawa, yayin da m daya ga sauran records suna dauke tagwaye.

ciko da database

Babban data ne matsayi database dabi'u (lambobi ko alamu) adana a cikin records. Kewaya irin wannan database ne yawanci daga kasa zuwa sama da kuma daga hagu zuwa dama.

girma

Tsari irin na danniya database - a database wanda ya tushen fayil, hankali sashe zuwa ƙasa. Ganin cewa irin wannan tsarin sosai kama da fayil tsarin, irin sansanonin an samu nasarar yi amfani da su na yin daban-daban ayyukan a kwamfuta data. Kasa line: da m kasafi na ta memory, da kuma wani sosai nagari yi lokaci ciyar a kan aiki.

The matsayi model ne manufa domin yin amfani domin ta ginannun bayanai.

shortcomings

Duk da haka, wannan halaye tattauna DBMSs cewa zama da babban abũbuwan amfãni, kuma ma sanin su shortcomings. Alal misali, mawuyaci da wahala da ma'ana sadarwa - dandana lokacin da akayi a baya ba a sani ba tushe zai zama da wuya a gane, kuma sauki mai amfani da kuma ba shi "samun rasa". Wannan haduwar take kaiwa zuwa wani fahimtar abin da ainihi ne ba yawa database gina a kan wani matsayi model. An misali ne a matsayi database, ban da riga aka bayyana samfurin "AyBiEm" kamfanin "Oka", kuma Mieris (Rasha samarwa), kazalika da Data Edge kuma Team-UP (daga waje hukumomi).

misalai

Tsari irin na danniya database - wani iri-iri daban-daban matakan da dangantaka an gina. Schematically, shi kama wani inverted jadawali. Wani misali da wani matsayi database - kowane jihar administrative ma'aikata. Dauki, misali, da makaranta.

A babba matakin za a located, "shugaba na" Administration - Director. A ta biyayya ga shugabancin malamai, shugaban malamai da - malamai suka duba daidaici azuzuwan. A kowane layi daya unspecified yawan su, da kuma kowane aji na da yawan dalibai.

A wannan manufa za a iya rubuta, da kuma gudanar da wani kamfani. The shugaban kamfanin ko da kwamitin gudanarwa a saman. Next - wani kara yawan raka'a a kowane daga wanda aiki da kansa tsarin. Akwai na kowa siffofin: m, a kowane sashi, mataimakansa, ya sakataren, a gaskiya, ofishin ma'aikatan, da sauransu.

A amfani da kwakwalwa a

Akwai iya zama mafi tsanani da aikace-aikace. A daukan hankali misali na matsayi data- tushe ne filesystem. Duk da saba "Windows Explorer" da aka gina a cikin kwaya daga cikin tsarin aiki "Vindous" Yana da ga irin wannan makirci, kazalika da yawa wasu fayil manajoji.

cibiyar sadarwa database

akwai:

• da zumunci.
• matsayi;
• online databases.

Don me muke sake tunãtar da su da rarrabuwa? Saboda, sabanin da zumunci, cibiyar sadarwa database yana da wani matsayi da kamanni.

Lokaci zuwa tuna da irin dangantaka a databases. Akwai dangane, "daya-to-daya", "daya-to-da yawa" da kuma "da yawa-to-da yawa". Mu ne sha'awar da karshen. A cibiyar sadarwa database aka bayyana kamar haka: daya gaje kumburi iya zama da dama da kakanninsu. Dũkiyar da ciwon mafi zuriya kuma ceto. Za mu iya cewa matsayi bayanai, cibiyar sadarwa databases da kansu su ne riga an misali na irin wannan gādo. M, a wannan yanayin ne kawai a matsayi database, kamar yadda wani manufa na yi na cibiyar sadarwa Tsarin cikin database ya zauna canzawa.

Matsayi da kuma zumunci

Sunan "zumunci" ya zo daga Turanci kalmar "hali". Kamar yadda aka ambata a baya a wannan labarin, su sukan bayyana a tabular form. Amma a sakin layi, za mu ce cewa matsayi database kuma iya shirya na sadarwa, ma'anar wannan cewa tsakanin wadannan nau'o'i guda biyu akwai wasu dabara thread haɗa kan bangaskiya su?

Na'am. Bugu da kari ya zama na farko da na biyu da irin har yanzu koma zuwa databases, ban da wannan alama akwai abu daya a cikin kowa. Alal misali, a matsayi database (cibiyar sadarwa da kuma na game da shi) za a iya bayyana a wani tebur. Batun nan ne ba a cikin nau'i a cikin abin da gabatar da bayanai zuwa karshen mai amfani (wannan shi ne tambaya na amfani dubawa), amma a kan abin da akai aka ginannun bayanai. Saboda haka, a sarari rabo a cikin sassan da su magabatansu, da kuma sauran raka'a zai ci gaba da za a bayyana, a matsayi, amma domin saukaka ne ya kawo wa tebur.