Imibuzo ihlanganisa amandla e-database yakho
Umbuzo wesisekelo udatha idatha kusuka database futhi uyifake ngendlela efundekayo. Umbuzo kufanele ubhalwe ngolimi oludinga database-ngokuvamile, lelo limi yi- SQL .
Isibonelo, uma ufuna idatha kusuka ku-database, usebenzisa umbuzo ukucela ulwazi oluthile olufunayo. Mhlawumbe unetafula labasebenzi, futhi ufuna ukulandelela izinombolo zokusebenza zokuthengisa. Ungase uphendule umgcini wakho we-database kumsebenzi orekhodile ukuthengisa okuphezulu esikhathini esinikeziwe.
Isitatimende SQL SELECT
Umbuzo wesisekelo kufanele ulandele ifomethi yombuzo edingekayo yi-database. Ifomethi evamile kakhulu yi-Structured Query Language (SQL) ifomethi yombuzo ojwayelekile osetshenziswa yizinhlelo eziningi zokuphathwa kwedatha. I-SQL iyilimi elinamandla elinemibuzo ephakeme.
I-SQL isebenzisa isitatimende sokukhetha ukukhetha idatha ethile.
Cabanga ngesibonelo esisekelwe ku-database yaseNorthwind evame ukuthumela ngemikhiqizo yedatha njengesifundo.
Nansi i-excerpt etafuleni labasebenzi base database:
| I-EmployeeID | Isibongo | Igama | Isihloko | Ikheli | Idolobha | Isifunda | |
|---|---|---|---|---|---|---|---|
| 1 | I-Davolio | Nancy | Abasebenzi bokuthengisa | 507 - 20th Ave. E. | Seattle | WA | |
| 2 | Okugcwele | Andrew |
| 908 W. Capital Way | I-Tacoma | WA | |
| 3 | I-Leverling | UJanet | Abasebenzi bokuthengisa | 722 Moss Bay Blvd. | I-Kirkland | WA |
Ukuze ubuyisele igama lomsebenzi nesitifiketi kusuka ku-database, isitatimende SELECT sibheke into enjengale:
Khetha i-FirstName, LastName, Isihloko kusuka kwabasebenzi;
Kuzobuya:
| Igama | Isibongo | Isihloko |
|---|---|---|
| Nancy | I-Davolio | Abasebenzi bokuthengisa |
| Andrew | Okugcwele | Vice President, Sales |
| UJanet | I-Leverling | Abasebenzi bokuthengisa |
Ukuhlunga imiphumela ngokuqhubekayo, ungangezela isigatshana se-WHERE:
Khetha i-FirstName, Igama lokugcina kusuka kwabasebenzi
LAPHO Umuzi = 'Tacoma';
Ibuyisa igama lokuqala negama lokugcina lomuntu noma yimuphi umsebenzi ovela ku-Tacoma:
| Igama | Isibongo |
|---|---|
| Andrew | Okugcwele |
Qaphela ukuthi i-SQL ibuyisela idatha efomini / ikholomu ifana ne-Microsoft Excel, eyenza kube lula ukubuka nokusebenza. Ezinye izilimi zombuzo zingabuyisa idatha njengegrafu noma ishadi.
Amandla Okubuza
I-database inekhono lokudalula izitayela eziyinkimbinkimbi nemisebenzi, kodwa leli gunya lihlanganiswa kuphela ngokusebenzisa umbuzo. Idatha eyinkimbinkimbi inamatafula amaningi agcina idatha eminingi. Umbuzo uvumela ukuwuhlunga kutafula elilodwa ukuze uhlaziye kalula.
Imibuzo nayo ingenza izibalo kudatha yakho noma yenza umsebenzi wokuphatha idatha. Ungabuyekeza izibuyekezo kudatha yakho ngaphambi kokuzinikela ku-database.