tailieunhanh - DATABASE NORMALIZATION

Additionally, with further information we were able to determine that a restatement that we had originally reported as having first been announced in 2000 was more appropriately classified as having first been announced in 1999. We are sending copies of this report to the Chairman of the Senate Committee on Banking, Housing, and Urban Affairs; the Chairmen and Ranking Minority Members of the Senate Committee on Governmental Affairs and the House Committee on Financial Services; and other interested congressional committees. We will also send copies to the Chairman of the SEC and will make copies available to others upon request. . | DATABASE NORMALIZATION Normalization process of efficiently organizing data in the DB. ị RELATIONS attributes grouped together ị Accurate representation of data relationships and constraints. Goal - Eliminate redundant data in a DB. - Ensure data dependencies make sense. Guidelines for ensuring that DBs are normalized normal forms 1NF 2NF 3NF BCNF. ị Normalization series of tests on a relation to determine whether it satisfies or violates the requirements of a normal form. Note meet practical business requirements. ị Normalization A technique for producing a set of relations with desirable properties given the data requirements of an enterprise. Reason for normalization to prevent possible corruption of DB stemming from update anomalies insertion deletion modification . EXAMPLE REDUNDANCY ANOMALIES STAFF RELATION SMcrtte SÂỔdrtti Pojrrjorr Salary SLĨL John White 19 Tailor Street Lotidan Manager ìữQŨữ SGỈT Ann Beech liOnrjr Sind. Glugow Snr Adit 12000 B3 SGI 4 Ford 6J Aibby Street GIIỈỆOM Deputy tiOW BJ EAÍ Mkry H we Ĩ Elm Place Aberdeen Asástinl woo BT 3Ũ5 Snikn Braud J Gl Walcm Ruad Gluts Manager MOW Bl SUI Julie Lm 11 Malvetn Street Kilburn Asỳ stint 90W B5 BRANCH RE1ATION Figure Staff and Branch relation 5 5 5 ii Deer Road Lộpdọn ló A ray II Street OLmiOw 163 Main Street 0la iow Of 71-S9ỂI-12 2 OIỈM-6712J STAFF BRANCH RELATION . . . - l- - J JNwne SAddfttr PtMir SdZiry flmacA_A o Addldrur- c SLĨI SGJT i SOI 4 ÌÍAĨ SGĨ SL4I John White AnnBaeẠ Dm Reft Maqf How SVMn liranii Julie Lee 19 Teyiar Stint London 1 Georte Siner gnw 6J Adibj1 Srrea. Gtetfow 1 Elm Place Aucrdnr 5 ũt Wetiern Rd Criesjow 1Í Mahcrn Street. Kilburn Muuctr Snr Ai l Deputy Aíiùtul Manlier AMhtniii J0300 lion IKDO 9000 2CW 9000 BS . BJ BO Bl Ĩ2 Décr Kaad l ndon IÍ3 Milu Sr red. CtafOU IÍỈ Main Sued GUifow IÍ Al ry J Street Aberdeen I6Ị Main Street. 2Ỉ IXĩi Knad London 0UI-W-I2I1 Ol4l-ỉỉf-IITt ỡi m-6 iii 0141-333-3131 Ol7l-uí-l3li FUNCTIONAL DEPENDENCIES Normalization a formal method