{"id":478510,"date":"2023-08-09T09:33:56","date_gmt":"2023-08-09T09:33:56","guid":{"rendered":""},"modified":"2023-09-05T11:16:56","modified_gmt":"2023-09-05T11:16:56","slug":"primary-key","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/primary-key\/","title":{"rendered":"Kh\u00f3a ch\u00ednh"},"content":{"rendered":"<p>Kh\u00f3a ch\u00ednh l\u00e0 m\u1ed9t thu\u1eadt ng\u1eef trong qu\u1ea3n l\u00fd v\u00e0 thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u bi\u1ec3u th\u1ecb m\u1ed9t c\u1ed9t c\u1ee5 th\u1ec3 (ho\u1eb7c k\u1ebft h\u1ee3p c\u00e1c c\u1ed9t) v\u1edbi m\u1ed9t gi\u00e1 tr\u1ecb duy nh\u1ea5t cho m\u1ed7i h\u00e0ng trong b\u1ea3ng c\u01a1 s\u1edf d\u1eef li\u1ec7u. \u0110i\u1ec1u n\u00e0y \u0111\u1ea3m b\u1ea3o r\u1eb1ng m\u1ed7i b\u1ea3n ghi trong b\u1ea3ng c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh duy nh\u1ea5t, n\u00e2ng cao t\u00ednh to\u00e0n v\u1eb9n v\u00e0 nh\u1ea5t qu\u00e1n c\u1ee7a d\u1eef li\u1ec7u.<\/p>\n<h2>L\u1ecbch s\u1eed ngu\u1ed3n g\u1ed1c c\u1ee7a kh\u00f3a ch\u00ednh v\u00e0 s\u1ef1 \u0111\u1ec1 c\u1eadp \u0111\u1ea7u ti\u00ean v\u1ec1 n\u00f3<\/h2>\n<p>Kh\u00e1i ni\u1ec7m kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 b\u1eaft ngu\u1ed3n t\u1eeb nh\u1eefng ng\u00e0y \u0111\u1ea7u c\u1ee7a l\u00fd thuy\u1ebft c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, do Ti\u1ebfn s\u0129 Edgar F. Codd kh\u1edfi x\u01b0\u1edbng v\u00e0o nh\u1eefng n\u0103m 1960. Ti\u1ebfn s\u0129 Codd \u0111\u00e3 gi\u1edbi thi\u1ec7u kh\u00e1i ni\u1ec7m v\u1ec1 ch\u00eca kh\u00f3a nh\u01b0 m\u1ed9t ph\u1ea7n thi\u1ebft y\u1ebfu trong m\u00f4 h\u00ecnh quan h\u1ec7 c\u1ee7a \u00f4ng. B\u1ea3n th\u00e2n thu\u1eadt ng\u1eef \u201ckh\u00f3a ch\u00ednh\u201d \u0111\u00e3 \u0111\u01b0\u1ee3c gi\u1edbi thi\u1ec7u sau \u0111\u00f3, khi c\u01a1 s\u1edf d\u1eef li\u1ec7u tr\u1edf n\u00ean ph\u1ee9c t\u1ea1p h\u01a1n, \u0111\u1ec3 ph\u00e2n bi\u1ec7t n\u00f3 v\u1edbi c\u00e1c lo\u1ea1i kh\u00f3a kh\u00e1c nh\u01b0 kh\u00f3a duy nh\u1ea5t v\u00e0 kh\u00f3a ngo\u1ea1i.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 Primary Key: M\u1edf r\u1ed9ng ch\u1ee7 \u0111\u1ec1 Primary Key<\/h2>\n<p>Kh\u00f3a ch\u00ednh \u0111\u00f3ng vai tr\u00f2 then ch\u1ed1t trong vi\u1ec7c x\u00e1c \u0111\u1ecbnh c\u1ea5u tr\u00fac c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7. B\u1eb1ng c\u00e1ch th\u1ef1c thi t\u00ednh duy nh\u1ea5t v\u00e0 ng\u0103n ch\u1eb7n c\u00e1c b\u1ea3n ghi tr\u00f9ng l\u1eb7p, kh\u00f3a ch\u00ednh gi\u00fap duy tr\u00ec t\u00ednh to\u00e0n v\u1eb9n c\u1ee7a d\u1eef li\u1ec7u. T\u00ednh duy nh\u1ea5t n\u00e0y \u0111\u01b0\u1ee3c th\u1ef1c thi th\u00f4ng qua c\u00e1c r\u00e0ng bu\u1ed9c m\u00e0 h\u1ec7 th\u1ed1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u ki\u1ec3m tra t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u00e8n ho\u1eb7c c\u1eadp nh\u1eadt d\u1eef li\u1ec7u.<\/p>\n<h3>\u0110\u1eb7c tr\u01b0ng:<\/h3>\n<ol>\n<li><strong>T\u00ednh duy nh\u1ea5t<\/strong>: Kh\u00f4ng c\u00f3 hai h\u00e0ng n\u00e0o c\u00f3 th\u1ec3 c\u00f3 c\u00f9ng gi\u00e1 tr\u1ecb kh\u00f3a ch\u00ednh.<\/li>\n<li><strong>Kh\u00f4ng c\u00f3 gi\u00e1 tr\u1ecb<\/strong>: Kh\u00f3a ch\u00ednh ph\u1ea3i ch\u1ee9a m\u1ed9t gi\u00e1 tr\u1ecb \u1edf m\u1ed7i h\u00e0ng.<\/li>\n<li><strong>T\u00ednh b\u1ea5t bi\u1ebfn<\/strong>: Sau khi \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh, gi\u00e1 tr\u1ecb c\u1ee7a kh\u00f3a ch\u00ednh s\u1ebd kh\u00f4ng thay \u0111\u1ed5i.<\/li>\n<li><strong>S\u1ef1 \u0111\u01a1n gi\u1ea3n<\/strong>: M\u1eb7c d\u00f9 kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 l\u00e0 h\u1ed7n h\u1ee3p (nhi\u1ec1u h\u01a1n m\u1ed9t c\u1ed9t), nh\u01b0ng th\u00f4ng th\u01b0\u1eddng b\u1ea1n n\u00ean gi\u1eef n\u00f3 c\u00e0ng \u0111\u01a1n gi\u1ea3n c\u00e0ng t\u1ed1t.<\/li>\n<\/ol>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a kh\u00f3a ch\u00ednh: Kh\u00f3a ch\u00ednh ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o<\/h2>\n<p>Kh\u00f3a ch\u00ednh ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1ch t\u1ea1o ch\u1ec9 m\u1ee5c tr\u00ean (c\u00e1c) c\u1ed9t c\u1ea5u th\u00e0nh kh\u00f3a. Ch\u1ec9 m\u1ee5c n\u00e0y cho ph\u00e9p h\u1ec7 th\u1ed1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u tra c\u1ee9u nhanh ch\u00f3ng c\u00e1c h\u00e0ng d\u1ef1a tr\u00ean c\u00e1c gi\u00e1 tr\u1ecb kh\u00f3a ch\u00ednh, \u0111\u1ea3m b\u1ea3o truy v\u1ea5n hi\u1ec7u qu\u1ea3.<\/p>\n<h3>C\u00e1c th\u00e0nh ph\u1ea7n:<\/h3>\n<ul>\n<li><strong>C\u1ed9t)<\/strong>: M\u1ed9t ho\u1eb7c nhi\u1ec1u c\u1ed9t t\u1ea1o th\u00e0nh kh\u00f3a ch\u00ednh.<\/li>\n<li><strong>H\u1ea1n ch\u1ebf<\/strong>: C\u00e1c quy t\u1eafc \u0111\u01b0\u1ee3c thi h\u00e0nh \u0111\u1ec3 duy tr\u00ec t\u00ednh duy nh\u1ea5t v\u00e0 c\u00e1c gi\u00e1 tr\u1ecb kh\u00f4ng r\u1ed7ng.<\/li>\n<li><strong>M\u1ee5c l\u1ee5c<\/strong>: M\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u \u0111\u1eb7c bi\u1ec7t t\u1ea1o \u0111i\u1ec1u ki\u1ec7n cho vi\u1ec7c t\u00ecm ki\u1ebfm v\u00e0 truy xu\u1ea5t nhanh ch\u00f3ng.<\/li>\n<\/ul>\n<h2>Ph\u00e2n t\u00edch c\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a kh\u00f3a ch\u00ednh<\/h2>\n<p>C\u00e1c t\u00ednh n\u0103ng c\u1ee7a kh\u00f3a ch\u00ednh mang l\u1ea1i m\u1ed9t s\u1ed1 l\u1ee3i \u00edch v\u00e0 th\u00e1ch th\u1ee9c trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u:<\/p>\n<h3>Nh\u1eefng l\u1ee3i \u00edch:<\/h3>\n<ul>\n<li><strong>To\u00e0n v\u1eb9n d\u1eef li\u1ec7u<\/strong>: \u0110\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c b\u1ea3n ghi l\u00e0 duy nh\u1ea5t v\u00e0 nh\u1ea5t qu\u00e1n.<\/li>\n<li><strong>C\u00e1c m\u1ed1i quan h\u1ec7<\/strong>: T\u1ea1o \u0111i\u1ec1u ki\u1ec7n thu\u1eadn l\u1ee3i cho m\u1ed1i quan h\u1ec7 v\u1edbi c\u00e1c b\u1ea3ng kh\u00e1c th\u00f4ng qua kh\u00f3a ngo\u1ea1i.<\/li>\n<li><strong>Truy v\u1ea5n hi\u1ec7u qu\u1ea3<\/strong>: N\u00e2ng cao hi\u1ec7u su\u1ea5t t\u00ecm ki\u1ebfm th\u00f4ng qua l\u1eadp ch\u1ec9 m\u1ee5c.<\/li>\n<\/ul>\n<h3>Nh\u1eefng th\u00e1ch th\u1ee9c:<\/h3>\n<ul>\n<li><strong>\u0110\u1ed9 ph\u1ee9c t\u1ea1p c\u1ee7a thi\u1ebft k\u1ebf<\/strong>: Vi\u1ec7c ch\u1ecdn \u0111\u00fang kh\u00f3a ch\u00ednh \u0111\u00f2i h\u1ecfi ph\u1ea3i xem x\u00e9t thi\u1ebft k\u1ebf c\u1ea9n th\u1eadn.<\/li>\n<li><strong>H\u1ea1n ch\u1ebf s\u1eeda \u0111\u1ed5i<\/strong>: Vi\u1ec7c thay \u0111\u1ed5i kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 ph\u1ee9c t\u1ea1p v\u00e0 r\u1ee7i ro.<\/li>\n<\/ul>\n<h2>C\u00e1c lo\u1ea1i kh\u00f3a ch\u00ednh: S\u1eed d\u1ee5ng b\u1ea3ng v\u00e0 danh s\u00e1ch \u0111\u1ec3 vi\u1ebft<\/h2>\n<p>Kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c chia th\u00e0nh c\u00e1c lo\u1ea1i sau:<\/p>\n<ol>\n<li><strong>Kh\u00f3a ch\u00ednh \u0111\u01a1n gi\u1ea3n<\/strong>: G\u1ed3m m\u1ed9t c\u1ed9t.<\/li>\n<li><strong>Kh\u00f3a ch\u00ednh t\u1ed5ng h\u1ee3p<\/strong>: G\u1ed3m nhi\u1ec1u c\u1ed9t.<\/li>\n<\/ol>\n<table>\n<thead>\n<tr>\n<th>Ki\u1ec3u<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Kh\u00f3a ch\u00ednh \u0111\u01a1n gi\u1ea3n<\/td>\n<td>S\u1eed d\u1ee5ng m\u1ed9t c\u1ed9t \u0111\u1ec3 th\u1ef1c thi t\u00ednh duy nh\u1ea5t.<\/td>\n<\/tr>\n<tr>\n<td>Kh\u00f3a ch\u00ednh t\u1ed5ng h\u1ee3p<\/td>\n<td>S\u1eed d\u1ee5ng nhi\u1ec1u c\u1ed9t \u0111\u1ec3 th\u1ef1c thi t\u00ednh duy nh\u1ea5t.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng kh\u00f3a ch\u00ednh, 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>Kh\u00f3a ch\u00ednh \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u lu\u00f4n nh\u1ea5t qu\u00e1n v\u00e0 c\u00f3 th\u1ec3 truy xu\u1ea5t d\u1ec5 d\u00e0ng. Tuy nhi\u00ean, ch\u00fang c\u0169ng c\u00f3 th\u1ec3 \u0111\u1eb7t ra nh\u1eefng th\u00e1ch th\u1ee9c.<\/p>\n<h3>Nh\u1eefng v\u1ea5n \u0111\u1ec1 chung:<\/h3>\n<ul>\n<li><strong>L\u1ef1a ch\u1ecdn kh\u00f3a sai<\/strong>: C\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn s\u1ef1 k\u00e9m hi\u1ec7u qu\u1ea3.<\/li>\n<li><strong>V\u1ea5n \u0111\u1ec1 di chuy\u1ec3n<\/strong>: Vi\u1ec7c thay \u0111\u1ed5i kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 ph\u1ee9c t\u1ea1p.<\/li>\n<\/ul>\n<h3>C\u00e1c gi\u1ea3i ph\u00e1p:<\/h3>\n<ul>\n<li><strong>Thi\u1ebft k\u1ebf c\u1ea9n th\u1eadn<\/strong>: Quy ho\u1ea1ch v\u00e0 thi\u1ebft k\u1ebf ph\u00f9 h\u1ee3p c\u00f3 th\u1ec3 gi\u1ea3m thi\u1ec3u h\u1ea7u h\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1.<\/li>\n<li><strong>C\u00f4ng c\u1ee5 v\u00e0 chuy\u00ean m\u00f4n<\/strong>: S\u1eed d\u1ee5ng c\u00e1c c\u00f4ng c\u1ee5 thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 ki\u1ebfn th\u1ee9c chuy\u00ean m\u00f4n.<\/li>\n<\/ul>\n<h2>C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m ch\u00ednh v\u00e0 nh\u1eefng so s\u00e1nh kh\u00e1c v\u1edbi c\u00e1c thu\u1eadt ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<table>\n<thead>\n<tr>\n<th>Thu\u1eadt ng\u1eef<\/th>\n<th>S\u1ef1 \u0111\u1ecbnh ngh\u0129a<\/th>\n<th>So s\u00e1nh v\u1edbi kh\u00f3a ch\u00ednh<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Kh\u00f3a ch\u00ednh<\/td>\n<td>X\u00e1c \u0111\u1ecbnh duy nh\u1ea5t m\u1ed9t b\u1ea3n ghi trong b\u1ea3ng.<\/td>\n<td>\u2013<\/td>\n<\/tr>\n<tr>\n<td>Ch\u00eca kh\u00f3a duy nh\u1ea5t<\/td>\n<td>Th\u1ef1c thi t\u00ednh duy nh\u1ea5t nh\u01b0ng c\u00f3 th\u1ec3 l\u00e0 null.<\/td>\n<td>\u00cdt nghi\u00eam ng\u1eb7t h\u01a1n kh\u00f3a ch\u00ednh.<\/td>\n<\/tr>\n<tr>\n<td>Kh\u00f3a ngo\u1ea1i<\/td>\n<td>Li\u00ean k\u1ebft hai b\u1ea3ng v\u1edbi nhau, tham chi\u1ebfu kh\u00f3a ch\u00ednh trong b\u1ea3ng kh\u00e1c.<\/td>\n<td>D\u00f9ng \u0111\u1ec3 c\u1ee7ng c\u1ed1 c\u00e1c m\u1ed1i quan h\u1ec7.<\/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 kh\u00f3a ch\u00ednh<\/h2>\n<p>T\u01b0\u01a1ng lai c\u1ee7a kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 s\u1ebd g\u1eafn li\u1ec1n v\u1edbi nh\u1eefng ti\u1ebfn b\u1ed9 trong c\u00f4ng ngh\u1ec7 c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 tr\u00ed tu\u1ec7 nh\u00e2n t\u1ea1o. Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u t\u1ef1 \u0111\u1ed9ng, c\u00e1c r\u00e0ng bu\u1ed9c to\u00e0n v\u1eb9n m\u1ea1nh m\u1ebd h\u01a1n v\u00e0 t\u00edch h\u1ee3p v\u1edbi c\u00e1c lo\u1ea1i c\u01a1 s\u1edf d\u1eef li\u1ec7u m\u1edbi (v\u00ed d\u1ee5: NoSQL) l\u00e0 nh\u1eefng l\u0129nh v\u1ef1c c\u1ea7n ch\u00fa \u00fd.<\/p>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng ho\u1eb7c li\u00ean k\u1ebft m\u00e1y ch\u1ee7 proxy v\u1edbi kh\u00f3a ch\u00ednh<\/h2>\n<p>Trong b\u1ed1i c\u1ea3nh c\u00e1c nh\u00e0 cung c\u1ea5p m\u00e1y ch\u1ee7 proxy nh\u01b0 OneProxy, kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u01a1 b\u1ea3n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 qu\u1ea3n l\u00fd c\u1ea5u h\u00ecnh m\u00e1y kh\u00e1ch, th\u00f4ng tin x\u00e1c th\u1ef1c ng\u01b0\u1eddi d\u00f9ng v\u00e0 nh\u1eadt k\u00fd. C\u1ea5u tr\u00fac c\u01a1 s\u1edf d\u1eef li\u1ec7u m\u1ea1nh m\u1ebd, bao g\u1ed3m vi\u1ec7c s\u1eed d\u1ee5ng ch\u00ednh x\u00e1c c\u00e1c kh\u00f3a ch\u00ednh, \u0111\u1ea3m b\u1ea3o ho\u1ea1t \u0111\u1ed9ng hi\u1ec7u qu\u1ea3, kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng v\u00e0 b\u1ea3o m\u1eadt c\u1ee7a c\u00e1c d\u1ecbch v\u1ee5 proxy.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<ol>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Relational_model\" target=\"_new\" rel=\"noopener nofollow\">L\u00fd thuy\u1ebft c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7 c\u1ee7a Edgar F. Codd<\/a><\/li>\n<li><a href=\"https:\/\/docs.microsoft.com\/en-us\/sql\/relational-databases\/databases\/database-design-basics?view=sql-server-ver15\" target=\"_new\" rel=\"noopener nofollow\">Kh\u00e1i ni\u1ec7m thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u<\/a><\/li>\n<li><a href=\"https:\/\/oneproxy.pro\/vn\/\" target=\"_new\" rel=\"noopener\">Trang web OneProxy<\/a> \u0111\u1ec3 bi\u1ebft th\u00eam th\u00f4ng tin v\u1ec1 c\u00e1ch c\u00e1c kh\u00f3a ch\u00ednh c\u00f3 th\u1ec3 li\u00ean quan trong b\u1ed1i c\u1ea3nh m\u00e1y ch\u1ee7 proxy.<\/li>\n<\/ol>\n<hr>\n<p>B\u00e0i vi\u1ebft n\u00e0y cung c\u1ea5p c\u00e1i nh\u00ecn t\u1ed5ng quan s\u00e2u r\u1ed9ng v\u1ec1 kh\u00e1i ni\u1ec7m kh\u00f3a ch\u00ednh, quan tr\u1ecdng \u0111\u1ed1i v\u1edbi b\u1ea5t k\u1ef3 ai tham gia thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u ho\u1eb7c quan t\u00e2m \u0111\u1ebfn vi\u1ec7c t\u00ecm hi\u1ec3u n\u1ec1n t\u1ea3ng c\u1ee7a qu\u1ea3n l\u00fd d\u1eef li\u1ec7u. \u0110\u1ed1i v\u1edbi c\u00e1c t\u1ed5 ch\u1ee9c nh\u01b0 OneProxy, vi\u1ec7c hi\u1ec3u vai tr\u00f2 c\u1ee7a kh\u00f3a ch\u00ednh trong c\u1ea5u tr\u00fac c\u01a1 s\u1edf d\u1eef li\u1ec7u l\u00e0 r\u1ea5t quan tr\u1ecdng \u0111\u1ec3 x\u00e2y d\u1ef1ng c\u00e1c h\u1ec7 th\u1ed1ng hi\u1ec7u qu\u1ea3 v\u00e0 c\u00f3 th\u1ec3 m\u1edf r\u1ed9ng.<\/p>","protected":false},"featured_media":469211,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-478510","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Primary Key<\/mark>","faq_items":[{"question":"What is a Primary Key?","answer":"<p>A primary key is a specific column or set of columns with a unique value for each row within a database table. It ensures that each record can be uniquely identified, maintaining data integrity and consistency.<\/p>"},{"question":"What are the Main Types of Primary Keys?","answer":"<p>There are two main types of primary keys: Simple Primary Key, which consists of a single column, and Composite Primary Key, which consists of multiple columns.<\/p>"},{"question":"How Does a Primary Key Work?","answer":"<p>A primary key works by creating an index on the column(s) that make up the key. This allows for quick lookup and retrieval of rows based on primary key values, aiding in efficient queries.<\/p>"},{"question":"What Are the Benefits and Challenges of Using a Primary Key?","answer":"<p>The benefits of using a primary key include ensuring data integrity, facilitating relationships with other tables, and enhancing search performance. Challenges may include design complexity and modification restrictions.<\/p>"},{"question":"How are Primary Keys Different from Unique Keys and Foreign Keys?","answer":"<p>Primary keys uniquely identify a record in a table and cannot be null. Unique keys also enforce uniqueness but can be null, while foreign keys are used to link two tables together and reference a primary key in another table.<\/p>"},{"question":"What Future Technologies and Perspectives are Related to Primary Keys?","answer":"<p>The future of primary keys may involve advancements in database technologies and artificial intelligence, including automated database design, more robust integrity constraints, and integration with new types of databases such as NoSQL.<\/p>"},{"question":"How are Proxy Servers like OneProxy Associated with Primary Keys?","answer":"<p>In the context of proxy server providers like OneProxy, primary keys might be part of the underlying databases used to manage client configurations, user credentials, and logs. Proper utilization of primary keys ensures the efficient operation, scalability, and security of proxy services.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/478510","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\/478510\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/469211"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=478510"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}