[工学]数据库关系数据库理论.pdf

1 6 Ù Xêâ¥nØ By Wei-gang Chen May 15, 2009 By Wei-gang Chen êâ¥p??§ có ùùù˜˜˜ÙÙÙÌÌ̇‡‡ SSSNNN ))): 1 cccóóó 2 ¼¼¼êêꝝ666 3 ¼¼¼êêꝝ666ÚÚÚèèè 4 úúúnnnXXXÚÚÚ 5 ááá555888 444 6 ÿÿÿÀÀÀèèè ¦¦¦))) 7 KKKCCCXXX 8 ‰‰‰ªªªnnnØØØ By Wei-gang Chen êâ¥p??§ có 333111ÙÙÙ ¥¥¥, ···‚‚‚òòòXXXªªª£££ãã㤤¤˜˜˜‡‡‡ 5 ||| R(U, D, dom, F), ÙÙÙ···‚‚‚555†††ªªªOOO———ƒƒƒƒƒƒ  U ÚÚÚ F. éé阘˜‡‡‡äääNNN¯¯¯KKK, kkk ±±±eeeAAA‡‡‡ÜÜÜ666OOO ¯¯¯KKKIII‡‡‡ ÄÄÄ: 1 AAATTTEEEAAA‡‡‡XXX(êêêââ⥥¥ ¥¥¥AAATTT¹¹¹AAA‡‡‡XXX)? 2 zzz‡‡‡XXXAAATTT dddAAA‡‡‡ááá555|||¤¤¤? - XXXÆÆÆ)))-ÀÀÀ‘‘‘êêêââ⥥¥, EEEXXXeee˜˜˜‡‡‡XXX´´´ÄÄÄÜÜÜnnn? SCA(Sno, Sname, Sage, Sdept, CNo, Cname, Cpno, Credit, Course) By Wei-gang Chen êâ¥p??§ có XXXêêêââ⥥¥OOO ¥¥¥333XXX˜˜˜ €€€²²²(pitfalls), ØØØÐÐÐ  OOO¬¬¬)))XXXeee¯¯¯KKK: 1 ;;;­­­EEEEEE(Repetition of Information). 2 ØØØUUULLL«««^^^rrrIII‡‡‡LLL«««EEE. By Wei-gang Chen êâ¥p??§ có ˜˜˜‡‡‡¢¢¢~~~: - PPP¹¹¹ÕÕÕ111EEE±±±999”””±±±rrrEEE, Lending(ÕÕÕ111¶¶¶, ÕÕÕ 111¤¤¤333¢¢¢½½½, ÕÕÕ111]]], rrr¶¶¶, ”””±±±ááárrrÒÒÒ, ”””±±±êêê) - ,,,‡‡‡žžžêêêââ⥥¥¢¢¢~~~(instance) By Wei-gang Chen êâ¥p??§ có LendingXXX333¯¯¯KKK: PPP{{{ 1 ,,,‡‡‡ÕÕÕ111kkkm‡‡‡”””±±±ááárrr, KKKTTTÕÕÕ111branch-name, branch-city, assetsEEE­­­EEEmggg, XXXDowntown; 2 ———