{"id":478222,"date":"2023-08-09T09:29:19","date_gmt":"2023-08-09T09:29:19","guid":{"rendered":""},"modified":"2023-09-05T11:16:19","modified_gmt":"2023-09-05T11:16:19","slug":"normalization","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/normalization\/","title":{"rendered":"Chu\u1ea9n h\u00f3a"},"content":{"rendered":"<p>Chu\u1ea9n h\u00f3a l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m quan tr\u1ecdng trong l\u0129nh v\u1ef1c x\u1eed l\u00fd d\u1eef li\u1ec7u, \u0111\u1eb7c bi\u1ec7t l\u00e0 trong c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 th\u1ed1ng k\u00ea. \u0110\u00f3 l\u00e0 qu\u00e1 tr\u00ecnh t\u1ed5 ch\u1ee9c v\u00e0 c\u1ea5u tr\u00fac d\u1eef li\u1ec7u theo c\u00e1ch chu\u1ea9n h\u00f3a \u0111\u1ec3 lo\u1ea1i b\u1ecf s\u1ef1 d\u01b0 th\u1eeba, gi\u1ea3m s\u1ef1 b\u1ea5t th\u01b0\u1eddng v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n c\u1ee7a d\u1eef li\u1ec7u. M\u1ee5c ti\u00eau ch\u00ednh c\u1ee7a vi\u1ec7c chu\u1ea9n h\u00f3a l\u00e0 t\u1ea1o ra m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c t\u1ed1t v\u00e0 hi\u1ec7u qu\u1ea3, t\u1ea1o \u0111i\u1ec1u ki\u1ec7n thu\u1eadn l\u1ee3i cho vi\u1ec7c truy xu\u1ea5t v\u00e0 ph\u00e2n t\u00edch d\u1eef li\u1ec7u. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang ta s\u1ebd kh\u00e1m ph\u00e1 l\u1ecbch s\u1eed, nguy\u00ean t\u1eafc, lo\u1ea1i v\u00e0 \u1ee9ng d\u1ee5ng c\u1ee7a chu\u1ea9n h\u00f3a c\u0169ng nh\u01b0 m\u1ed1i quan h\u1ec7 c\u1ee7a n\u00f3 v\u1edbi m\u00e1y ch\u1ee7 proxy.<\/p>\n<h2>L\u1ecbch s\u1eed v\u1ec1 ngu\u1ed3n g\u1ed1c c\u1ee7a Chu\u1ea9n h\u00f3a v\u00e0 l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u1ec1 c\u1eadp \u0111\u1ebfn n\u00f3<\/h2>\n<p>Kh\u00e1i ni\u1ec7m chu\u1ea9n h\u00f3a trong b\u1ed1i c\u1ea3nh c\u01a1 s\u1edf d\u1eef li\u1ec7u l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c Ti\u1ebfn s\u0129 Edgar F. Codd gi\u1edbi thi\u1ec7u trong b\u00e0i b\u00e1o chuy\u00ean \u0111\u1ec1 c\u1ee7a \u00f4ng c\u00f3 t\u1ef1a \u0111\u1ec1 \u201cM\u00f4 h\u00ecnh d\u1eef li\u1ec7u quan h\u1ec7 cho c\u00e1c ng\u00e2n h\u00e0ng d\u1eef li\u1ec7u d\u00f9ng chung l\u1edbn\u201d xu\u1ea5t b\u1ea3n n\u0103m 1970. Ti\u1ebfn s\u0129 Codd, m\u1ed9t nh\u00e0 nghi\u00ean c\u1ee9u c\u1ee7a IBM, \u0111\u00e3 \u0111\u1ec1 xu\u1ea5t m\u00f4 h\u00ecnh quan h\u1ec7, tr\u1edf th\u00e0nh n\u1ec1n t\u1ea3ng c\u1ee7a h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u hi\u1ec7n \u0111\u1ea1i (DBMS). Trong b\u00e0i vi\u1ebft n\u00e0y, \u00f4ng \u0111\u00e3 ph\u00e1c th\u1ea3o c\u00e1c nguy\u00ean t\u1eafc c\u01a1 b\u1ea3n c\u1ee7a chu\u1ea9n h\u00f3a, c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u00e1c d\u1ea1ng chu\u1ea9n h\u00f3a, sau n\u00e0y ph\u00e1t tri\u1ec3n th\u00e0nh nhi\u1ec1u giai \u0111o\u1ea1n kh\u00e1c nhau \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u1ee9c \u0111\u1ed9 chu\u1ea9n h\u00f3a cao h\u01a1n.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 Chu\u1ea9n h\u00f3a<\/h2>\n<p>Chu\u1ea9n h\u00f3a bao g\u1ed3m vi\u1ec7c chia c\u01a1 s\u1edf d\u1eef li\u1ec7u th\u00e0nh c\u00e1c b\u1ea3ng nh\u1ecf h\u01a1n, d\u1ec5 qu\u1ea3n l\u00fd h\u01a1n, gi\u1ea3m s\u1ef1 d\u01b0 th\u1eeba d\u1eef li\u1ec7u v\u00e0 thi\u1ebft l\u1eadp m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c b\u1ea3ng n\u00e0y. Qu\u00e1 tr\u00ecnh n\u00e0y kh\u00f4ng ch\u1ec9 t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c l\u01b0u tr\u1eef d\u1eef li\u1ec7u m\u00e0 c\u00f2n c\u1ea3i thi\u1ec7n t\u00ednh to\u00e0n v\u1eb9n v\u00e0 nh\u1ea5t qu\u00e1n c\u1ee7a d\u1eef li\u1ec7u. Qu\u00e1 tr\u00ecnh chu\u1ea9n h\u00f3a \u0111\u01b0\u1ee3c l\u1eb7p \u0111i l\u1eb7p l\u1ea1i v\u00e0 tu\u00e2n theo m\u1ed9t b\u1ed9 quy t\u1eafc, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 d\u1ea1ng chu\u1ea9n h\u00f3a, \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o t\u00ednh hi\u1ec7u qu\u1ea3 v\u00e0 ch\u00ednh x\u00e1c c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/p>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a Chu\u1ea9n h\u00f3a: C\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a Chu\u1ea9n h\u00f3a<\/h2>\n<p>Qu\u00e1 tr\u00ecnh chu\u1ea9n h\u00f3a d\u1ef1a tr\u00ean m\u1ed9t lo\u1ea1t c\u00e1c bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng, m\u1ed7i bi\u1ec3u m\u1eabu \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng tr\u00ean bi\u1ec3u m\u1eabu tr\u01b0\u1edbc \u0111\u00f3 \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c c\u1ea5p \u0111\u1ed9 t\u1ed5 ch\u1ee9c d\u1eef li\u1ec7u cao h\u01a1n. C\u00e1c d\u1ea1ng chu\u1ea9n th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0:<\/p>\n<ol>\n<li>Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng \u0111\u1ea7u ti\u00ean (1NF): \u0110\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed7i c\u1ed9t ch\u1ee9a c\u00e1c gi\u00e1 tr\u1ecb nguy\u00ean t\u1eed v\u00e0 kh\u00f4ng c\u00f3 nh\u00f3m ho\u1eb7c m\u1ea3ng l\u1eb7p l\u1ea1i trong m\u1ed9t h\u00e0ng.<\/li>\n<li>Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng th\u1ee9 hai (2NF): Ngo\u00e0i vi\u1ec7c \u0111\u00e1p \u1ee9ng ti\u00eau ch\u00ed 1NF, n\u00f3 c\u00f2n \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed7i c\u1ed9t kh\u00f4ng kh\u00f3a \u0111\u1ec1u ph\u1ee5 thu\u1ed9c \u0111\u1ea7y \u0111\u1ee7 ch\u1ee9c n\u0103ng v\u00e0o to\u00e0n b\u1ed9 kh\u00f3a ch\u00ednh.<\/li>\n<li>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng th\u1ee9 ba (3NF): B\u00ean c\u1ea1nh vi\u1ec7c \u0111\u00e1p \u1ee9ng 2NF, n\u00f3 c\u00f2n lo\u1ea1i b\u1ecf c\u00e1c ph\u1ee5 thu\u1ed9c b\u1eafc c\u1ea7u, trong \u0111\u00f3 m\u1ed9t c\u1ed9t kh\u00f4ng kh\u00f3a ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ed9t c\u1ed9t kh\u00f4ng kh\u00f3a kh\u00e1c th\u00f4ng qua kh\u00f3a ch\u00ednh.<\/li>\n<li>Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng Boyce-Codd (BCNF): M\u1ed9t bi\u1ec3u m\u1eabu n\u00e2ng cao gi\u00fap lo\u1ea1i b\u1ecf s\u1ef1 ph\u1ee5 thu\u1ed9c m\u1ed9t ph\u1ea7n, \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed7i c\u1ed9t kh\u00f4ng kh\u00f3a \u0111\u1ec1u ph\u1ee5 thu\u1ed9c ch\u1ee9c n\u0103ng v\u00e0o to\u00e0n b\u1ed9 kh\u00f3a ch\u00ednh.<\/li>\n<li>Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng th\u1ee9 t\u01b0 (4NF): Bi\u1ec3u m\u1eabu n\u00e0y x\u1eed l\u00fd c\u00e1c ph\u1ee5 thu\u1ed9c \u0111a gi\u00e1 tr\u1ecb, trong \u0111\u00f3 m\u1ed9t ho\u1eb7c nhi\u1ec1u c\u1ed9t kh\u00f4ng kh\u00f3a ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ed9t t\u1eadp h\u1ee3p c\u00e1c gi\u00e1 tr\u1ecb \u0111\u1ed9c l\u1eadp v\u1edbi kh\u00f3a ch\u00ednh.<\/li>\n<li>Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng th\u1ee9 n\u0103m (5NF): C\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 Bi\u1ec3u m\u1eabu th\u00f4ng th\u01b0\u1eddng tham gia d\u1ef1 \u00e1n (PJNF), n\u00f3 gi\u1ea3i quy\u1ebft c\u00e1c tr\u01b0\u1eddng h\u1ee3p b\u1ea3ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c b\u1ea3ng nh\u1ecf h\u01a1n, hi\u1ec7u qu\u1ea3 h\u01a1n m\u00e0 kh\u00f4ng l\u00e0m m\u1ea5t b\u1ea5t k\u1ef3 th\u00f4ng tin n\u00e0o.<\/li>\n<\/ol>\n<h2>Ph\u00e2n t\u00edch c\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a Chu\u1ea9n h\u00f3a<\/h2>\n<p>C\u00e1c t\u00ednh n\u0103ng v\u00e0 l\u1ee3i \u00edch ch\u00ednh c\u1ee7a vi\u1ec7c chu\u1ea9n h\u00f3a bao g\u1ed3m:<\/p>\n<ol>\n<li>T\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u: Chu\u1ea9n h\u00f3a l\u00e0m gi\u1ea3m s\u1ef1 d\u01b0 th\u1eeba v\u00e0 kh\u00f4ng nh\u1ea5t qu\u00e1n c\u1ee7a d\u1eef li\u1ec7u, th\u00fac \u0111\u1ea9y t\u00ednh to\u00e0n v\u1eb9n v\u00e0 ch\u00ednh x\u00e1c c\u1ee7a d\u1eef li\u1ec7u.<\/li>\n<li>L\u01b0u tr\u1eef hi\u1ec7u qu\u1ea3: B\u1eb1ng c\u00e1ch chia nh\u1ecf c\u00e1c b\u1ea3ng, qu\u00e1 tr\u00ecnh chu\u1ea9n h\u00f3a s\u1ebd t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c l\u01b0u tr\u1eef v\u00e0 truy xu\u1ea5t d\u1eef li\u1ec7u, d\u1eabn \u0111\u1ebfn hi\u1ec7u su\u1ea5t t\u1ed1t h\u01a1n.<\/li>\n<li>Kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng: C\u01a1 s\u1edf d\u1eef li\u1ec7u chu\u1ea9n h\u00f3a c\u00f3 c\u1ea5u tr\u00fac t\u1ed1t c\u00f3 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng v\u00e0 th\u00edch \u1ee9ng t\u1ed1t h\u01a1n v\u1edbi c\u00e1c y\u00eau c\u1ea7u thay \u0111\u1ed5i.<\/li>\n<li>B\u1ea3o tr\u00ec d\u1ec5 d\u00e0ng h\u01a1n: Chu\u1ea9n h\u00f3a gi\u00fap \u0111\u01a1n gi\u1ea3n h\u00f3a vi\u1ec7c b\u1ea3o tr\u00ec c\u01a1 s\u1edf d\u1eef li\u1ec7u, gi\u00fap c\u1eadp nh\u1eadt v\u00e0 s\u1eeda \u0111\u1ed5i d\u1eef li\u1ec7u d\u1ec5 d\u00e0ng h\u01a1n m\u00e0 kh\u00f4ng g\u00e2y ra s\u1ef1 b\u1ea5t th\u01b0\u1eddng.<\/li>\n<li>Truy v\u1ea5n \u0111\u01a1n gi\u1ea3n h\u00f3a: C\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c chu\u1ea9n h\u00f3a t\u1ea1o \u0111i\u1ec1u ki\u1ec7n truy v\u1ea5n \u0111\u01a1n gi\u1ea3n v\u00e0 hi\u1ec7u qu\u1ea3, n\u00e2ng cao kh\u1ea3 n\u0103ng ph\u00e2n t\u00edch d\u1eef li\u1ec7u.<\/li>\n<\/ol>\n<h2>C\u00e1c lo\u1ea1i chu\u1ea9n h\u00f3a<\/h2>\n<p>Chu\u1ea9n h\u00f3a bao g\u1ed3m nhi\u1ec1u giai \u0111o\u1ea1n, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 c\u00e1c d\u1ea1ng chu\u1ea9n h\u00f3a. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 t\u1ed5ng quan v\u1ec1 t\u1eebng h\u00ecnh th\u1ee9c th\u00f4ng th\u01b0\u1eddng v\u00e0 c\u00e1c y\u00eau c\u1ea7u c\u1ee7a n\u00f3:<\/p>\n<table>\n<thead>\n<tr>\n<th>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng<\/th>\n<th>Y\u00eau c\u1ea7u<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>D\u1ea1ng b\u00ecnh th\u01b0\u1eddng \u0111\u1ea7u ti\u00ean (1NF)<\/td>\n<td>\u2013 Lo\u1ea1i b\u1ecf c\u00e1c nh\u00f3m v\u00e0 m\u1ea3ng l\u1eb7p l\u1ea1i trong c\u00e1c h\u00e0ng.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 \u0110\u1ea3m b\u1ea3o m\u1ed7i c\u1ed9t ch\u1ee9a c\u00e1c gi\u00e1 tr\u1ecb nguy\u00ean t\u1eed.<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng th\u1ee9 hai (2NF)<\/td>\n<td>\u2013 \u0110\u00e1p \u1ee9ng ti\u00eau ch\u00ed 1NF.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 \u0110\u1ea3m b\u1ea3o m\u1ed7i c\u1ed9t kh\u00f4ng kh\u00f3a \u0111\u1ec1u ph\u1ee5 thu\u1ed9c \u0111\u1ea7y \u0111\u1ee7 ch\u1ee9c n\u0103ng v\u00e0o to\u00e0n b\u1ed9 kh\u00f3a ch\u00ednh.<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng th\u1ee9 ba (3NF)<\/td>\n<td>\u2013 \u0110\u00e1p \u1ee9ng y\u00eau c\u1ea7u 2NF.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 Lo\u1ea1i b\u1ecf s\u1ef1 ph\u1ee5 thu\u1ed9c b\u1eafc c\u1ea7u gi\u1eefa c\u00e1c c\u1ed9t kh\u00f4ng kh\u00f3a v\u00e0 kh\u00f3a ch\u00ednh.<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea1ng chu\u1ea9n Boyce-Codd (BCNF)<\/td>\n<td>\u2013 \u0110\u00e1p \u1ee9ng ti\u00eau ch\u00ed 3NF.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 Lo\u1ea1i b\u1ecf s\u1ef1 ph\u1ee5 thu\u1ed9c m\u1ed9t ph\u1ea7n.<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng th\u1ee9 t\u01b0 (4NF)<\/td>\n<td>\u2013 \u0110\u00e1p \u1ee9ng y\u00eau c\u1ea7u BCNF.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 X\u1eed l\u00fd c\u00e1c ph\u1ee5 thu\u1ed9c \u0111a gi\u00e1 tr\u1ecb, lo\u1ea1i b\u1ecf d\u1eef li\u1ec7u d\u01b0 th\u1eeba.<\/td>\n<\/tr>\n<tr>\n<td>D\u1ea1ng th\u00f4ng th\u01b0\u1eddng th\u1ee9 n\u0103m (5NF)<\/td>\n<td>\u2013 \u0110\u00e1p \u1ee9ng ti\u00eau ch\u00ed 4NF.<\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td>\u2013 Gi\u1ea3i quy\u1ebft c\u00e1c tr\u01b0\u1eddng h\u1ee3p b\u1ea3ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c b\u1ea3ng nh\u1ecf h\u01a1n, hi\u1ec7u qu\u1ea3 h\u01a1n m\u00e0 kh\u00f4ng l\u00e0m m\u1ea5t th\u00f4ng tin.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng Chu\u1ea9n h\u00f3a, c\u00e1c v\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p li\u00ean quan \u0111\u1ebfn vi\u1ec7c s\u1eed d\u1ee5ng<\/h2>\n<p>Chu\u1ea9n h\u00f3a \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong c\u00e1c ng\u00e0nh kh\u00e1c nhau, bao g\u1ed3m t\u00e0i ch\u00ednh, ch\u0103m s\u00f3c s\u1ee9c kh\u1ecfe, th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed, v.v. Tuy nhi\u00ean, vi\u1ec7c s\u1eed d\u1ee5ng chu\u1ea9n h\u00f3a kh\u00f4ng \u0111\u00fang c\u00e1ch c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 nh\u1ea5t \u0111\u1ecbnh, ch\u1eb3ng h\u1ea1n nh\u01b0:<\/p>\n<ol>\n<li>\n<p><strong>Sao ch\u00e9p d\u1eef li\u1ec7u<\/strong>: Chu\u1ea9n h\u00f3a qu\u00e1 m\u1ee9c c\u00f3 th\u1ec3 g\u00e2y ra s\u1ef1 tr\u00f9ng l\u1eb7p d\u1eef li\u1ec7u kh\u00f4ng c\u1ea7n thi\u1ebft tr\u00ean nhi\u1ec1u b\u1ea3ng, d\u1eabn \u0111\u1ebfn y\u00eau c\u1ea7u l\u01b0u tr\u1eef t\u0103ng l\u00ean.<\/p>\n<\/li>\n<li>\n<p><strong>Tham gia ph\u1ee9c t\u1ea1p<\/strong>: C\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c chu\u1ea9n h\u00f3a cao c\u00f3 th\u1ec3 y\u00eau c\u1ea7u c\u00e1c ph\u00e9p n\u1ed1i ph\u1ee9c t\u1ea1p \u0111\u1ec3 truy xu\u1ea5t d\u1eef li\u1ec7u, c\u00f3 kh\u1ea3 n\u0103ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t truy v\u1ea5n.<\/p>\n<\/li>\n<li>\n<p><strong>C\u1eadp nh\u1eadt c\u00e1c \u0111i\u1ec3m b\u1ea5t th\u01b0\u1eddng<\/strong>: Vi\u1ec7c ch\u00e8n ho\u1eb7c c\u1eadp nh\u1eadt d\u1eef li\u1ec7u trong m\u1ed9t b\u1ea3ng \u0111\u00e3 chu\u1ea9n h\u00f3a c\u00f3 th\u1ec3 y\u00eau c\u1ea7u s\u1eeda \u0111\u1ed5i nhi\u1ec1u b\u1ea3ng c\u00f3 li\u00ean quan, l\u00e0m t\u0103ng kh\u1ea3 n\u0103ng x\u1ea3y ra c\u00e1c \u0111i\u1ec3m b\u1ea5t th\u01b0\u1eddng khi c\u1eadp nh\u1eadt.<\/p>\n<\/li>\n<\/ol>\n<p>\u0110\u1ec3 gi\u1ea3i quy\u1ebft nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y, ng\u01b0\u1eddi thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u ph\u1ea3i \u0111\u1ea1t \u0111\u01b0\u1ee3c s\u1ef1 c\u00e2n b\u1eb1ng gi\u1eefa chu\u1ea9n h\u00f3a v\u00e0 kh\u00f4ng chu\u1ea9n h\u00f3a. Vi\u1ec7c kh\u00f4ng chu\u1ea9n h\u00f3a li\u00ean quan \u0111\u1ebfn vi\u1ec7c \u0111\u01b0a l\u1ea1i t\u00ednh d\u1ef1 ph\u00f2ng \u0111\u1ec3 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t truy v\u1ea5n v\u00e0 \u0111\u01a1n gi\u1ea3n h\u00f3a vi\u1ec7c truy xu\u1ea5t d\u1eef li\u1ec7u. Tuy nhi\u00ean, n\u00f3 n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng m\u1ed9t c\u00e1ch th\u1eadn tr\u1ecdng \u0111\u1ec3 tr\u00e1nh \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u.<\/p>\n<h2>C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m ch\u00ednh v\u00e0 so s\u00e1nh kh\u00e1c v\u1edbi c\u00e1c thu\u1eadt ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<h3>Chu\u1ea9n h\u00f3a v\u00e0 kh\u00f4ng chu\u1ea9n h\u00f3a<\/h3>\n<p>Chu\u1ea9n h\u00f3a v\u00e0 kh\u00f4ng chu\u1ea9n h\u00f3a l\u00e0 hai k\u1ef9 thu\u1eadt \u0111\u1ed1i l\u1eadp nhau trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u. Trong khi chu\u1ea9n h\u00f3a t\u1eadp trung v\u00e0o vi\u1ec7c gi\u1ea3m s\u1ef1 d\u01b0 th\u1eeba v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n c\u1ee7a d\u1eef li\u1ec7u, th\u00ec vi\u1ec7c chu\u1ea9n h\u00f3a l\u1ea1i nh\u1eb1m m\u1ee5c \u0111\u00edch c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t truy v\u1ea5n b\u1eb1ng c\u00e1ch \u0111\u01b0a l\u1ea1i t\u00ednh d\u01b0 th\u1eeba. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 so s\u00e1nh:<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0111\u1eb7c tr\u01b0ng<\/th>\n<th>Chu\u1ea9n h\u00f3a<\/th>\n<th>Kh\u00f4ng chu\u1ea9n h\u00f3a<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>To\u00e0n v\u1eb9n d\u1eef li\u1ec7u<\/td>\n<td>\u0110\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u cao b\u1eb1ng c\u00e1ch gi\u1ea3m s\u1ef1 d\u01b0 th\u1eeba v\u00e0 duy tr\u00ec m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c b\u1ea3ng.<\/td>\n<td>C\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn d\u01b0 th\u1eeba d\u1eef li\u1ec7u v\u00e0 c\u00f3 th\u1ec3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u n\u1ebfu kh\u00f4ng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n c\u1ea9n th\u1eadn.<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u su\u1ea5t truy v\u1ea5n<\/td>\n<td>C\u00f3 th\u1ec3 li\u00ean quan \u0111\u1ebfn c\u00e1c ph\u00e9p n\u1ed1i ph\u1ee9c t\u1ea1p, c\u00f3 kh\u1ea3 n\u0103ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t truy v\u1ea5n.<\/td>\n<td>C\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t truy v\u1ea5n b\u1eb1ng c\u00e1ch gi\u1ea3m thi\u1ec3u c\u00e1c ph\u00e9p n\u1ed1i v\u00e0 \u0111\u01a1n gi\u1ea3n h\u00f3a vi\u1ec7c truy xu\u1ea5t d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u qu\u1ea3 l\u01b0u tr\u1eef<\/td>\n<td>T\u1ed1i \u01b0u h\u00f3a vi\u1ec7c l\u01b0u tr\u1eef b\u1eb1ng c\u00e1ch chia nh\u1ecf c\u00e1c b\u1ea3ng v\u00e0 gi\u1ea3m tr\u00f9ng l\u1eb7p.<\/td>\n<td>C\u00f3 th\u1ec3 t\u0103ng y\u00eau c\u1ea7u l\u01b0u tr\u1eef do d\u01b0 th\u1eeba d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n<tr>\n<td>Tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng<\/td>\n<td>L\u00fd t\u01b0\u1edfng cho c\u00e1c h\u1ec7 th\u1ed1ng giao d\u1ecbch n\u01a1i t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u l\u00e0 r\u1ea5t quan tr\u1ecdng.<\/td>\n<td>Th\u00edch h\u1ee3p cho c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00edch, kho d\u1eef li\u1ec7u v\u00e0 b\u00e1o c\u00e1o trong \u0111\u00f3 t\u1ed1c \u0111\u1ed9 truy v\u1ea5n l\u00e0 \u0111i\u1ec1u c\u1ea7n thi\u1ebft.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m v\u00e0 c\u00f4ng ngh\u1ec7 c\u1ee7a t\u01b0\u01a1ng lai li\u00ean quan \u0111\u1ebfn B\u00ecnh th\u01b0\u1eddng h\u00f3a<\/h2>\n<p>Khi c\u00f4ng ngh\u1ec7 ph\u00e1t tri\u1ec3n, c\u00e1c nguy\u00ean t\u1eafc b\u00ecnh th\u01b0\u1eddng h\u00f3a c\u00f3 th\u1ec3 s\u1ebd v\u1eabn ph\u00f9 h\u1ee3p. Tuy nhi\u00ean, nh\u1eefng ti\u1ebfn b\u1ed9 m\u1edbi trong h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 x\u1eed l\u00fd d\u1eef li\u1ec7u c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn c\u00e1c k\u1ef9 thu\u1eadt chu\u1ea9n h\u00f3a hi\u1ec7u qu\u1ea3 h\u01a1n. M\u1ed9t l\u0129nh v\u1ef1c h\u1ee9a h\u1eb9n cho t\u01b0\u01a1ng lai c\u1ee7a qu\u00e1 tr\u00ecnh b\u00ecnh th\u01b0\u1eddng h\u00f3a l\u00e0 s\u1ef1 t\u00edch h\u1ee3p gi\u1eefa tr\u00ed tu\u1ec7 nh\u00e2n t\u1ea1o v\u00e0 h\u1ecdc m\u00e1y. AI c\u00f3 kh\u1ea3 n\u0103ng t\u1ef1 \u0111\u1ed9ng h\u00f3a qu\u00e1 tr\u00ecnh chu\u1ea9n h\u00f3a, ph\u00e2n t\u00edch m\u1eabu d\u1eef li\u1ec7u v\u00e0 \u0111\u1ec1 xu\u1ea5t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u t\u1ed1i \u01b0u, ti\u1ebft ki\u1ec7m th\u1eddi gian v\u00e0 c\u00f4ng s\u1ee9c cho c\u00e1c nh\u00e0 thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/p>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng ho\u1eb7c li\u00ean k\u1ebft m\u00e1y ch\u1ee7 proxy v\u1edbi Chu\u1ea9n h\u00f3a<\/h2>\n<p>M\u00e1y ch\u1ee7 proxy \u0111\u00f3ng m\u1ed9t vai tr\u00f2 quan tr\u1ecdng trong giao ti\u1ebfp m\u1ea1ng b\u1eb1ng c\u00e1ch \u0111\u00f3ng vai tr\u00f2 trung gian gi\u1eefa m\u00e1y kh\u00e1ch v\u00e0 m\u00e1y ch\u1ee7. M\u1eb7c d\u00f9 ch\u00fang kh\u00f4ng li\u00ean quan tr\u1ef1c ti\u1ebfp \u0111\u1ebfn vi\u1ec7c chu\u1ea9n h\u00f3a nh\u01b0ng m\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 g\u00f3p ph\u1ea7n b\u1ea3o m\u1eadt d\u1eef li\u1ec7u, quy\u1ec1n ri\u00eang t\u01b0 v\u00e0 hi\u1ec7u su\u1ea5t. B\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng m\u00e1y ch\u1ee7 proxy, doanh nghi\u1ec7p c\u00f3 th\u1ec3:<\/p>\n<ol>\n<li>\n<p><strong>T\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt<\/strong>: M\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 che gi\u1ea5u \u0111\u1ecba ch\u1ec9 IP c\u1ee7a kh\u00e1ch h\u00e0ng, th\u00eam m\u1ed9t l\u1edbp \u1ea9n danh b\u1ed5 sung v\u00e0 b\u1ea3o v\u1ec7 d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m kh\u1ecfi c\u00e1c m\u1ed1i \u0111e d\u1ecda ti\u1ec1m \u1ea9n.<\/p>\n<\/li>\n<li>\n<p><strong>B\u1ed9 nh\u1edb \u0111\u1ec7m d\u1eef li\u1ec7u<\/strong>: Proxy c\u00f3 th\u1ec3 l\u01b0u v\u00e0o b\u1ed9 \u0111\u1ec7m d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c truy c\u1eadp th\u01b0\u1eddng xuy\u00ean, gi\u1ea3m t\u1ea3i cho m\u00e1y ch\u1ee7 v\u00e0 c\u1ea3i thi\u1ec7n t\u1ed1c \u0111\u1ed9 truy xu\u1ea5t d\u1eef li\u1ec7u.<\/p>\n<\/li>\n<li>\n<p><strong>L\u1ecdc n\u1ed9i dung<\/strong>: M\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 l\u1ecdc v\u00e0 ch\u1eb7n n\u1ed9i dung kh\u00f4ng mong mu\u1ed1n, \u0111\u1ea3m b\u1ea3o tu\u00e2n th\u1ee7 c\u00e1c ch\u00ednh s\u00e1ch v\u00e0 quy \u0111\u1ecbnh c\u1ee7a c\u00f4ng ty.<\/p>\n<\/li>\n<li>\n<p><strong>C\u00e2n b\u1eb1ng t\u1ea3i<\/strong>: Proxy c\u00f3 th\u1ec3 ph\u00e2n ph\u1ed1i l\u01b0u l\u01b0\u1ee3ng truy c\u1eadp \u0111\u1ebfn tr\u00ean nhi\u1ec1u m\u00e1y ch\u1ee7, t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c s\u1eed d\u1ee5ng t\u00e0i nguy\u00ean v\u00e0 c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t t\u1ed5ng th\u1ec3.<\/p>\n<\/li>\n<li>\n<p><strong>Gi\u00e1m s\u00e1t v\u00e0 ghi nh\u1eadt k\u00fd<\/strong>: Proxy c\u00f3 th\u1ec3 ghi nh\u1eadt k\u00fd v\u00e0 ph\u00e2n t\u00edch l\u01b0u l\u01b0\u1ee3ng m\u1ea1ng, gi\u00fap x\u00e1c \u0111\u1ecbnh v\u00e0 gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 ti\u1ec1m \u1ea9n.<\/p>\n<\/li>\n<\/ol>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<p>\u0110\u1ec3 bi\u1ebft th\u00eam th\u00f4ng tin v\u1ec1 chu\u1ea9n h\u00f3a, b\u1ea1n c\u00f3 th\u1ec3 kh\u00e1m ph\u00e1 c\u00e1c t\u00e0i nguy\u00ean sau:<\/p>\n<ul>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Database_normalization\" target=\"_new\" rel=\"noopener nofollow\">Chu\u1ea9n h\u00f3a c\u01a1 s\u1edf d\u1eef li\u1ec7u - Wikipedia<\/a><\/li>\n<li><a href=\"https:\/\/www.essentialsql.com\/get-ready-to-learn-sql-database-normalization-explained-in-simple-english\/\" target=\"_new\" rel=\"noopener nofollow\">Gi\u1edbi thi\u1ec7u v\u1ec1 chu\u1ea9n h\u00f3a c\u01a1 s\u1edf d\u1eef li\u1ec7u<\/a><\/li>\n<li><a href=\"https:\/\/www.geeksforgeeks.org\/normalization-in-database-management-system\/\" target=\"_new\" rel=\"noopener nofollow\">Chu\u1ea9n h\u00f3a trong qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u<\/a><\/li>\n<li><a href=\"https:\/\/www.cloudflare.com\/learning\/network-layer\/what-is-a-proxy-server\/\" target=\"_new\" rel=\"noopener nofollow\">T\u00ecm hi\u1ec3u m\u00e1y ch\u1ee7 proxy<\/a><\/li>\n<\/ul>\n<p>T\u00f3m l\u1ea1i, chu\u1ea9n h\u00f3a l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n trong qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u nh\u1eb1m \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n v\u00e0 t\u1ed5 ch\u1ee9c d\u1eef li\u1ec7u hi\u1ec7u qu\u1ea3. B\u1eb1ng c\u00e1ch tu\u00e2n th\u1ee7 c\u00e1c nguy\u00ean t\u1eafc chu\u1ea9n h\u00f3a, doanh nghi\u1ec7p c\u00f3 th\u1ec3 x\u00e2y d\u1ef1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u m\u1ea1nh m\u1ebd c\u00f3 kh\u1ea3 n\u0103ng x\u1eed l\u00fd d\u1eef li\u1ec7u m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c v\u00e0 \u0111\u00e1ng tin c\u1eady. H\u01a1n n\u1eefa, vi\u1ec7c t\u00edch h\u1ee3p m\u00e1y ch\u1ee7 proxy v\u1edbi t\u00ednh n\u0103ng chu\u1ea9n h\u00f3a c\u00f3 th\u1ec3 t\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt d\u1eef li\u1ec7u, quy\u1ec1n ri\u00eang t\u01b0 v\u00e0 hi\u1ec7u su\u1ea5t, cung c\u1ea5p gi\u1ea3i ph\u00e1p to\u00e0n di\u1ec7n cho c\u00e1c doanh nghi\u1ec7p d\u1ef1a tr\u00ean d\u1eef li\u1ec7u hi\u1ec7n \u0111\u1ea1i.<\/p>","protected":false},"featured_media":469023,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-478222","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Normalization: A Comprehensive Guide<\/mark>","faq_items":[{"question":"What is normalization, and why is it important in database management?","answer":"<p>Normalization is the process of structuring data in a standardized manner to eliminate redundancy and ensure data integrity in a database. It is crucial in database management as it optimizes data storage, improves data retrieval efficiency, and maintains accurate and consistent information.<\/p>"},{"question":"Who introduced the concept of normalization, and when was it first mentioned?","answer":"<p>The concept of normalization was introduced by Dr. Edgar F. Codd, an IBM researcher, in his 1970 paper titled \"A Relational Model of Data for Large Shared Data Banks.\" This paper outlined the principles of normalization and laid the foundation for modern database management systems.<\/p>"},{"question":"How does normalization work, and what are the key features?","answer":"<p>Normalization works by applying a series of normal forms, each building on the previous one, to organize and structure data efficiently. The key features of normalization include improved data integrity, efficient storage, scalability, easier maintenance, and simplified queries.<\/p>"},{"question":"What are the types of normalization, and what do they entail?","answer":"<p>There are several types of normalization, each represented by a normal form. These include:<\/p><ol><li>First Normal Form (1NF): Eliminating repeating groups and ensuring atomic values in columns.<\/li><li>Second Normal Form (2NF): Meeting 1NF criteria and ensuring full functional dependency on the primary key for non-key columns.<\/li><li>Third Normal Form (3NF): Satisfying 2NF requirements and eliminating transitive dependencies between non-key columns and the primary key.<\/li><li>Boyce-Codd Normal Form (BCNF): Satisfying 3NF criteria and eliminating partial dependencies.<\/li><li>Fourth Normal Form (4NF): Satisfying BCNF requirements and handling multi-valued dependencies.<\/li><li>Fifth Normal Form (5NF): Satisfying 4NF criteria and addressing cases where a table can be broken down into smaller, more efficient tables.<\/li><\/ol>"},{"question":"What are the challenges related to normalization, and how can they be resolved?","answer":"<p>Challenges related to normalization include data duplication, complex joins, and update anomalies. These can be mitigated by striking a balance between normalization and denormalization, where denormalization reintroduces some redundancy to improve query performance while maintaining data integrity.<\/p>"},{"question":"How does normalization relate to the future of technology, particularly AI and machine learning?","answer":"<p>As technology advances, normalization will remain relevant, and new techniques may emerge to enhance the process. The integration of AI and machine learning holds promise in automating normalization, analyzing data patterns, and suggesting optimal data structures, making database design more efficient.<\/p>"},{"question":"How are proxy servers associated with normalization, and what benefits do they offer?","answer":"<p>While not directly related to normalization, proxy servers play a significant role in enhancing data security, privacy, and performance. They can mask IP addresses, cache data, filter content, balance loads, and provide monitoring and logging capabilities, contributing to a secure and efficient data environment.<\/p>"},{"question":"Where can I find more information about normalization and related topics?","answer":"<p>For more in-depth information about normalization and its applications, you can explore the following resources:<\/p><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Database_normalization\" target=\"_new\">Database Normalization - Wikipedia<\/a><\/li><li><a href=\"https:\/\/www.essentialsql.com\/get-ready-to-learn-sql-database-normalization-explained-in-simple-english\/\" target=\"_new\">An Introduction to Database Normalization<\/a><\/li><li><a href=\"https:\/\/www.geeksforgeeks.org\/normalization-in-database-management-system\/\" target=\"_new\">Normalization in Database Management System<\/a><\/li><li><a href=\"https:\/\/www.cloudflare.com\/learning\/network-layer\/what-is-a-proxy-server\/\" target=\"_new\">Understanding Proxy Servers<\/a><\/li><\/ul>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/478222","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/478222\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/469023"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=478222"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}