{"id":476664,"date":"2023-08-09T07:31:20","date_gmt":"2023-08-09T07:31:20","guid":{"rendered":""},"modified":"2023-09-05T11:13:11","modified_gmt":"2023-09-05T11:13:11","slug":"data-manipulation-language","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/data-manipulation-language\/","title":{"rendered":"Ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u"},"content":{"rendered":"<p>Ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u (DML) l\u00e0 m\u1ed9t t\u1eadp h\u1ee3p con c\u1ee7a SQL (Ng\u00f4n ng\u1eef truy v\u1ea5n c\u00f3 c\u1ea5u tr\u00fac) \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 truy xu\u1ea5t, ch\u00e8n, s\u1eeda \u0111\u1ed5i v\u00e0 x\u00f3a d\u1eef li\u1ec7u trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. M\u1ee5c \u0111\u00edch ch\u00ednh c\u1ee7a DML l\u00e0 cung c\u1ea5p m\u1ed9t c\u00e1ch linh ho\u1ea1t v\u00e0 hi\u1ec7u qu\u1ea3 \u0111\u1ec3 thao t\u00e1c d\u1eef li\u1ec7u trong m\u00f4i tr\u01b0\u1eddng c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac.<\/p>\n<h2>L\u1ecbch s\u1eed v\u00e0 s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>Ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u c\u00f3 ngu\u1ed3n g\u1ed1c t\u1eeb s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a SQL trong nh\u1eefng n\u0103m 1970. SQL \u0111\u01b0\u1ee3c t\u1ea1o ra b\u1edfi Raymond F. Boyce v\u00e0 Donald D. Chamberlin t\u1ea1i IBM. L\u1ea7n \u0111\u1ea7u ti\u00ean h\u1ecd gi\u1edbi thi\u1ec7u DML nh\u01b0 m\u1ed9t ph\u1ea7n c\u1ee7a ng\u00f4n ng\u1eef SQL trong m\u1ed9t b\u00e0i b\u00e1o n\u0103m 1974 c\u00f3 t\u00ean \u201cSEQUEL: A Structured English Query Language\u201d. Theo th\u1eddi gian, DML \u0111\u00e3 ph\u00e1t tri\u1ec3n v\u00e0 \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng r\u1ed9ng r\u00e3i trong nhi\u1ec1u h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u (DBMS), tr\u1edf th\u00e0nh m\u1ed9t ph\u1ea7n ti\u00eau chu\u1ea9n c\u1ee7a c\u00e1c ti\u00eau chu\u1ea9n ANSI v\u00e0 ISO SQL.<\/p>\n<h2>M\u1ed9t c\u00e1i nh\u00ecn s\u00e2u s\u1eafc v\u1ec1 ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>C\u00e1c l\u1ec7nh DML l\u00e0 trung t\u00e2m c\u1ee7a SQL v\u00e0 cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng thao t\u00e1c v\u1edbi d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. B\u1ed1n l\u1ec7nh ch\u00ednh trong DML bao g\u1ed3m:<\/p>\n<ol>\n<li><strong>L\u1ef0A CH\u1eccN<\/strong>: D\u00f9ng \u0111\u1ec3 truy v\u1ea5n v\u00e0 l\u1ea5y d\u1eef li\u1ec7u t\u1eeb m\u1ed9t ho\u1eb7c nhi\u1ec1u b\u1ea3ng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n<li><strong>CH\u00c8N<\/strong>: Th\u00eam b\u1ea3n ghi m\u1edbi v\u00e0o b\u1ea3ng.<\/li>\n<li><strong>C\u1eacP NH\u1eacT<\/strong>: S\u1eeda \u0111\u1ed5i c\u00e1c b\u1ea3n ghi hi\u1ec7n c\u00f3 trong m\u1ed9t b\u1ea3ng.<\/li>\n<li><strong>X\u00d3A B\u1ece<\/strong>: X\u00f3a b\u1ea3n ghi kh\u1ecfi b\u1ea3ng.<\/li>\n<\/ol>\n<p>\u0110i\u1ec1u quan tr\u1ecdng l\u00e0 ph\u1ea3i hi\u1ec3u r\u1eb1ng c\u00e1c l\u1ec7nh n\u00e0y, \u0111\u1eb7c bi\u1ec7t l\u00e0 UPDATE v\u00e0 DELETE, c\u00f3 th\u1ec3 thay \u0111\u1ed5i \u0111\u00e1ng k\u1ec3 d\u1eef li\u1ec7u trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. V\u00ec v\u1eady, c\u00e1ch t\u1ed1t nh\u1ea5t l\u00e0 th\u1ef1c hi\u1ec7n c\u00e1c l\u1ec7nh nh\u01b0 v\u1eady m\u1ed9t c\u00e1ch th\u1eadn tr\u1ecdng.<\/p>\n<h2>Ho\u1ea1t \u0111\u1ed9ng b\u00ean trong c\u1ee7a ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>\u1ede c\u1ea5p \u0111\u1ed9 c\u01a1 b\u1ea3n, DML ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1ch g\u1eedi l\u1ec7nh \u0111\u1ebfn h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u. DBMS di\u1ec5n gi\u1ea3i c\u00e1c l\u1ec7nh n\u00e0y, th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u tr\u00ean d\u1eef li\u1ec7u v\u00e0 tr\u1ea3 v\u1ec1 m\u1ecdi d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u cho ng\u01b0\u1eddi d\u00f9ng. DBMS x\u1eed l\u00fd t\u1ea5t c\u1ea3 s\u1ef1 ph\u1ee9c t\u1ea1p c\u1ee7a vi\u1ec7c truy c\u1eadp v\u00e0 l\u01b0u tr\u1eef d\u1eef li\u1ec7u, gi\u00fap ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 t\u01b0\u01a1ng t\u00e1c v\u1edbi d\u1eef li\u1ec7u b\u1eb1ng c\u00e1c l\u1ec7nh t\u01b0\u01a1ng \u0111\u1ed1i \u0111\u01a1n gi\u1ea3n.<\/p>\n<p>V\u1ec1 m\u1eb7t th\u1ef1c thi, h\u1ec7 th\u1ed1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u x\u1eed l\u00fd l\u1ec7nh DML theo hai giai \u0111o\u1ea1n:<\/p>\n<ol>\n<li><strong>Th\u1eddi gian bi\u00ean d\u1ecbch<\/strong>: C\u00fa ph\u00e1p c\u1ee7a c\u00e2u l\u1ec7nh SQL \u0111\u01b0\u1ee3c ki\u1ec3m tra.<\/li>\n<li><strong>Th\u1eddi gian ch\u1ea1y<\/strong>: H\u1ec7 th\u1ed1ng c\u01a1 s\u1edf d\u1eef li\u1ec7u th\u1ef1c thi c\u00e2u l\u1ec7nh SQL v\u00e0 th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c d\u1eef li\u1ec7u.<\/li>\n<\/ol>\n<h2>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>M\u1ed9t s\u1ed1 t\u00ednh n\u0103ng quan tr\u1ecdng c\u1ee7a DML bao g\u1ed3m:<\/p>\n<ul>\n<li><strong>S\u1ef1 \u0111\u01a1n gi\u1ea3n<\/strong>: C\u00e1c l\u1ec7nh DML r\u1ea5t \u0111\u01a1n gi\u1ea3n v\u00e0 d\u1ec5 hi\u1ec3u.<\/li>\n<li><strong>Uy\u1ec3n chuy\u1ec3n<\/strong>: DML cho ph\u00e9p thao t\u00e1c d\u1eef li\u1ec7u \u1edf c\u1ea3 c\u1ea5p \u0111\u1ed9 b\u1ea3n ghi v\u00e0 t\u1eadp h\u1ee3p.<\/li>\n<li><strong>X\u1eed l\u00fd d\u1eef li\u1ec7u m\u1ea1nh m\u1ebd<\/strong>: DML c\u00f3 th\u1ec3 x\u1eed l\u00fd m\u1ed9t l\u01b0\u1ee3ng l\u1edbn d\u1eef li\u1ec7u m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3.<\/li>\n<li><strong>T\u00ednh nh\u1ea5t qu\u00e1n c\u1ee7a d\u1eef li\u1ec7u<\/strong>: DML \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n v\u00e0 nh\u1ea5t qu\u00e1n c\u1ee7a d\u1eef li\u1ec7u trong c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n<\/ul>\n<h2>C\u00e1c lo\u1ea1i ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>C\u00f3 hai lo\u1ea1i DML:<\/p>\n<ol>\n<li><strong>DML th\u1ee7 t\u1ee5c<\/strong>: Y\u00eau c\u1ea7u ng\u01b0\u1eddi d\u00f9ng ch\u1ec9 \u0111\u1ecbnh d\u1eef li\u1ec7u n\u00e0o l\u00e0 c\u1ea7n thi\u1ebft v\u00e0 c\u00e1ch l\u1ea5y d\u1eef li\u1ec7u \u0111\u00f3.<\/li>\n<li><strong>DML phi th\u1ee7 t\u1ee5c<\/strong>: Y\u00eau c\u1ea7u ng\u01b0\u1eddi d\u00f9ng ch\u1ec9 \u0111\u1ecbnh d\u1eef li\u1ec7u n\u00e0o l\u00e0 c\u1ea7n thi\u1ebft m\u00e0 kh\u00f4ng ch\u1ec9 \u0111\u1ecbnh c\u00e1ch l\u1ea5y d\u1eef li\u1ec7u \u0111\u00f3.<\/li>\n<\/ol>\n<p>B\u1ea3ng sau \u0111\u00e2y cung c\u1ea5p s\u1ef1 so s\u00e1nh gi\u1eefa hai lo\u1ea1i:<\/p>\n<table>\n<thead>\n<tr>\n<th>T\u00ednh n\u0103ng<\/th>\n<th>DML th\u1ee7 t\u1ee5c<\/th>\n<th>DML phi th\u1ee7 t\u1ee5c<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>D\u1ec5 s\u1eed d\u1ee5ng<\/td>\n<td>Y\u00eau c\u1ea7u ki\u1ebfn th\u1ee9c v\u1ec1 c\u00e1ch l\u01b0u tr\u1eef d\u1eef li\u1ec7u<\/td>\n<td>D\u1ec5 d\u00e0ng h\u01a1n cho ng\u01b0\u1eddi d\u00f9ng, ch\u1ec9 c\u1ea7n c\u00f3 ki\u1ebfn th\u1ee9c v\u1ec1 d\u1eef li\u1ec7u c\u1ea7n thi\u1ebft<\/td>\n<\/tr>\n<tr>\n<td>Hi\u1ec7u qu\u1ea3<\/td>\n<td>C\u00f3 th\u1ec3 hi\u1ec7u qu\u1ea3 h\u01a1n v\u00ec ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 \u0111i\u1ec1u khi\u1ec3n h\u1ec7 th\u1ed1ng m\u1ed9t c\u00e1ch c\u1ee5 th\u1ec3 h\u01a1n<\/td>\n<td>C\u00f3 th\u1ec3 k\u00e9m hi\u1ec7u qu\u1ea3 h\u01a1n v\u00ec h\u1ec7 th\u1ed1ng ph\u1ea3i x\u00e1c \u0111\u1ecbnh c\u00e1ch t\u1ed1t nh\u1ea5t \u0111\u1ec3 truy xu\u1ea5t d\u1eef li\u1ec7u<\/td>\n<\/tr>\n<tr>\n<td>V\u00ed d\u1ee5<\/td>\n<td>SQL khi \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng v\u1edbi JOIN, WHERE v\u00e0 c\u00e1c l\u1ec7nh t\u01b0\u01a1ng t\u1ef1 kh\u00e1c<\/td>\n<td>SQL khi \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng v\u1edbi c\u00e1c c\u00e2u l\u1ec7nh SELECT c\u01a1 b\u1ea3n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng, v\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p trong ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>DML \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong nhi\u1ec1u \u1ee9ng d\u1ee5ng, t\u1eeb truy xu\u1ea5t d\u1eef li\u1ec7u \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 b\u00e1o c\u00e1o \u0111\u1ebfn thao t\u00e1c d\u1eef li\u1ec7u ph\u1ee9c t\u1ea1p trong c\u00e1c \u1ee9ng d\u1ee5ng ph\u1ea7n m\u1ec1m. Tuy nhi\u00ean, vi\u1ec7c s\u1eed d\u1ee5ng DML kh\u00f4ng \u0111\u00fang c\u00e1ch c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn h\u1ecfng d\u1eef li\u1ec7u, m\u1ea5t d\u1eef li\u1ec7u v\u00e0 c\u00e1c v\u1ea5n \u0111\u1ec1 v\u1ec1 hi\u1ec7u su\u1ea5t.<\/p>\n<p>\u0110\u1ec3 gi\u1ea3m thi\u1ec3u nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y, m\u1ed9t s\u1ed1 ph\u01b0\u01a1ng ph\u00e1p hay nh\u1ea5t bao g\u1ed3m:<\/p>\n<ul>\n<li>S\u1eed d\u1ee5ng c\u00e1c giao d\u1ecbch \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u.<\/li>\n<li>H\u1ea1n ch\u1ebf s\u1eed d\u1ee5ng c\u00e1c l\u1ec7nh X\u00d3A v\u00e0 C\u1eacP NH\u1eacT \u0111\u1ec3 tr\u00e1nh m\u1ea5t d\u1eef li\u1ec7u do v\u00f4 t\u00ecnh.<\/li>\n<li>Th\u01b0\u1eddng xuy\u00ean sao l\u01b0u c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n<li>\u00c1p d\u1ee5ng quy\u1ec1n ng\u01b0\u1eddi d\u00f9ng ph\u00f9 h\u1ee3p \u0111\u1ec3 gi\u1edbi h\u1ea1n ng\u01b0\u1eddi c\u00f3 th\u1ec3 th\u1ef1c thi c\u00e1c l\u1ec7nh DML.<\/li>\n<\/ul>\n<h2>So s\u00e1nh v\u1edbi c\u00e1c ng\u00f4n ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<p>Trong khi SQL v\u00e0 do \u0111\u00f3 DML \u0111\u00e3 tr\u1edf th\u00e0nh c\u00f4ng c\u1ee5 ti\u00eau chu\u1ea9n trong qu\u1ea3n l\u00fd c\u01a1 s\u1edf d\u1eef li\u1ec7u, c\u00e1c ng\u00f4n ng\u1eef kh\u00e1c c\u0169ng cung c\u1ea5p kh\u1ea3 n\u0103ng thao t\u00e1c d\u1eef li\u1ec7u. Hai v\u00ed d\u1ee5 \u0111\u00e1ng ch\u00fa \u00fd l\u00e0 XQuery d\u00e0nh cho c\u01a1 s\u1edf d\u1eef li\u1ec7u XML v\u00e0 SPARQL d\u00e0nh cho c\u01a1 s\u1edf d\u1eef li\u1ec7u RDF.<\/p>\n<p>C\u00e1c ng\u00f4n ng\u1eef n\u00e0y c\u00f3 tr\u1ecdng t\u00e2m kh\u00e1c v\u1edbi SQL v\u00e0 DML, v\u1edbi XQuery t\u1eadp trung v\u00e0o c\u1ea5u tr\u00fac d\u1eef li\u1ec7u gi\u1ed1ng nh\u01b0 t\u00e0i li\u1ec7u v\u00e0 SPARQL tr\u00ean d\u1eef li\u1ec7u web ng\u1eef ngh\u0129a. Tuy nhi\u00ean, ch\u00fang cung c\u1ea5p c\u00e1c kh\u1ea3 n\u0103ng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 c\u00e1c l\u1ec7nh CH\u1eccN, CH\u00c8N, C\u1eacP NH\u1eacT v\u00e0 X\u00d3A \u0111\u01b0\u1ee3c t\u00ecm th\u1ea5y trong DML.<\/p>\n<h2>Tri\u1ec3n v\u1ecdng t\u01b0\u01a1ng lai cho ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>Khi c\u01a1 s\u1edf d\u1eef li\u1ec7u ti\u1ebfp t\u1ee5c l\u00e0 n\u1ec1n t\u1ea3ng c\u1ee7a c\u00f4ng ngh\u1ec7 th\u00f4ng tin, t\u1ea7m quan tr\u1ecdng c\u1ee7a DML s\u1ebd v\u1eabn c\u00f2n \u0111\u00e1ng k\u1ec3. S\u1ef1 ph\u00e1t tri\u1ec3n nh\u01b0 c\u01a1 s\u1edf d\u1eef li\u1ec7u NoSQL v\u00e0 n\u1ec1n t\u1ea3ng D\u1eef li\u1ec7u l\u1edbn \u0111\u00e3 t\u1ea1o ra nh\u1eefng th\u00e1ch th\u1ee9c v\u00e0 c\u01a1 h\u1ed9i m\u1edbi. S\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a DML ho\u1eb7c s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a c\u00e1c ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u m\u1edbi \u0111\u1ec3 gi\u1ea3i quy\u1ebft nh\u1eefng th\u00e1ch th\u1ee9c n\u00e0y s\u1ebd l\u00e0 m\u1ed9t kh\u00f4ng gian h\u1ea5p d\u1eabn \u0111\u1ec3 theo d\u00f5i.<\/p>\n<h2>S\u1ef1 giao thoa gi\u1eefa m\u00e1y ch\u1ee7 proxy v\u00e0 ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u<\/h2>\n<p>M\u00e1y ch\u1ee7 proxy ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t trung gian gi\u1eefa m\u00e1y kh\u00e1ch \u0111ang t\u00ecm ki\u1ebfm t\u00e0i nguy\u00ean t\u1eeb c\u00e1c m\u00e1y ch\u1ee7 kh\u00e1c. M\u1eb7c d\u00f9 c\u00e1c m\u00e1y ch\u1ee7 proxy v\u1ed1n kh\u00f4ng t\u01b0\u01a1ng t\u00e1c v\u1edbi DML nh\u01b0ng ch\u00fang c\u00f3 th\u1ec3 \u0111\u00f3ng vai tr\u00f2 qu\u1ea3n l\u00fd c\u00e1c y\u00eau c\u1ea7u c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u0169ng nh\u01b0 duy tr\u00ec t\u00ednh b\u1ea3o m\u1eadt v\u00e0 \u1ea9n danh.<\/p>\n<p>V\u00ed d\u1ee5: m\u00e1y ch\u1ee7 proxy c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh \u0111\u1ec3 c\u00e2n b\u1eb1ng t\u1ea3i y\u00eau c\u1ea7u DML tr\u00ean nhi\u1ec1u c\u01a1 s\u1edf d\u1eef li\u1ec7u, c\u1ea3i thi\u1ec7n hi\u1ec7u su\u1ea5t. Ngo\u00e0i ra, b\u1eb1ng c\u00e1ch \u0111\u1ecbnh tuy\u1ebfn c\u00e1c y\u00eau c\u1ea7u c\u01a1 s\u1edf d\u1eef li\u1ec7u th\u00f4ng qua m\u00e1y ch\u1ee7 proxy, m\u1ed9t l\u1edbp \u1ea9n danh v\u00e0 b\u1ea3o m\u1eadt b\u1ed5 sung s\u1ebd \u0111\u01b0\u1ee3c th\u00eam v\u00e0o quy tr\u00ecnh thao t\u00e1c d\u1eef li\u1ec7u, gi\u1ea3m nguy c\u01a1 thao t\u00fang d\u1eef li\u1ec7u \u0111\u1ed9c h\u1ea1i.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.w3schools.com\/sql\/default.asp\" target=\"_new\" rel=\"noopener nofollow\">H\u01b0\u1edbng d\u1eabn SQL c\u1ee7a W3Schools<\/a><\/li>\n<li><a href=\"https:\/\/www.dataversity.net\/sql-foundation-data-manipulation\/\" target=\"_new\" rel=\"noopener nofollow\">SQL: N\u1ec1n t\u1ea3ng cho thao t\u00e1c d\u1eef li\u1ec7u<\/a><\/li>\n<li><a href=\"https:\/\/docs.oracle.com\/cd\/B19306_01\/server.102\/b14200\/statements_10002.htm\" target=\"_new\" rel=\"noopener nofollow\">Ng\u00f4n ng\u1eef thao t\u00e1c d\u1eef li\u1ec7u c\u1ee7a Oracle<\/a><\/li>\n<\/ul>\n<p>B\u1eb1ng c\u00e1ch hi\u1ec3u v\u00e0 t\u1eadn d\u1ee5ng \u0111\u00fang c\u00e1ch DML, ng\u01b0\u1eddi ta c\u00f3 th\u1ec3 t\u01b0\u01a1ng t\u00e1c v\u00e0 thao t\u00e1c d\u1eef li\u1ec7u m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3 trong m\u00f4i tr\u01b0\u1eddng c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac, \u0111\u00e2y l\u00e0 m\u1ed9t k\u1ef9 n\u0103ng quan tr\u1ecdng trong th\u1ebf gi\u1edbi ng\u00e0y c\u00e0ng d\u1ef1a tr\u00ean d\u1eef li\u1ec7u c\u1ee7a ch\u00fang ta.<\/p>","protected":false},"featured_media":476665,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-476664","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Data Manipulation Language: A Comprehensive Guide<\/mark>","faq_items":[{"question":"What is Data Manipulation Language?","answer":"<p>Data Manipulation Language (DML) is a subset of SQL (Structured Query Language) used to retrieve, insert, modify, and delete data in a database. It is primarily designed to facilitate efficient and flexible manipulation of data within a structured database environment.<\/p>"},{"question":"What is the history of Data Manipulation Language?","answer":"<p>DML originated from the development of SQL in the 1970s by Raymond F. Boyce and Donald D. Chamberlin at IBM. They first introduced DML as part of the SQL language in a 1974 paper called \"SEQUEL: A Structured English Query Language\". Since then, DML has evolved and has been widely adopted in various database management systems (DBMS), becoming a standard part of ANSI and ISO SQL standards.<\/p>"},{"question":"What are the key features of Data Manipulation Language?","answer":"<p>Key features of DML include simplicity, flexibility, powerful data handling, and data consistency. DML commands are simple and easy to understand, allow data manipulation at both record and set levels, can efficiently handle a large volume of data, and ensure the integrity and consistency of the data within the database.<\/p>"},{"question":"What are the types of Data Manipulation Language?","answer":"<p>There are two types of DML: Procedural and Non-Procedural. Procedural DML requires a user to specify what data is needed and how to get it. In contrast, Non-Procedural DML requires a user to specify what data is needed without dictating how to get it.<\/p>"},{"question":"What problems can arise from using Data Manipulation Language, and how can they be solved?","answer":"<p>Improper use of DML can result in data corruption, data loss, and performance issues. These problems can be mitigated by using transactions to ensure data integrity, limiting the use of the DELETE and UPDATE commands to prevent accidental data loss, regularly backing up the database, and applying appropriate user permissions to limit who can execute DML commands.<\/p>"},{"question":"How are proxy servers associated with Data Manipulation Language?","answer":"<p>While proxy servers don't inherently interact with DML, they can be configured to manage database requests, thereby maintaining security and anonymity. For instance, a proxy server can balance the load of DML requests across multiple databases, improving performance. Additionally, by routing database requests through a proxy server, an extra layer of security and anonymity is added to the data manipulation process.<\/p>"},{"question":"What are the future prospects for Data Manipulation Language?","answer":"<p>As databases continue to be central to information technology, DML's relevance is expected to remain significant. With the advent of NoSQL databases and Big Data platforms, there are new challenges and opportunities for DML. The evolution of DML to handle these challenges, or the development of new data manipulation languages, is an area to watch in the future.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/476664","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\/476664\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/476665"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=476664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}