{"id":9289,"date":"2025-04-10T16:24:37","date_gmt":"2025-04-10T09:24:37","guid":{"rendered":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/?p=9289"},"modified":"2025-04-10T16:24:38","modified_gmt":"2025-04-10T09:24:38","slug":"mo-hinh-hoa-du-lieu-la-gi","status":"publish","type":"post","link":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/tu-van-nghe-nghiep\/mo-hinh-hoa-du-lieu-la-gi","title":{"rendered":"M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 g\u00ec? L\u1ee3i \u00edch v\u00e0 nh\u1eefng sai l\u1ea7m c\u1ea7n tr\u00e1nh"},"content":{"rendered":"\n
Thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng th\u00f4ng tin hi\u1ec7u qu\u1ea3 lu\u00f4n \u0111\u00f2i h\u1ecfi s\u1ef1 hi\u1ec3u bi\u1ebft r\u00f5 r\u00e0ng v\u1ec1 c\u00e1ch d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c v\u00e0 v\u1eadn h\u00e0nh. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 g\u00ec<\/strong> m\u00e0 l\u1ea1i gi\u1eef vai tr\u00f2 n\u1ec1n t\u1ea3ng nh\u01b0 v\u1eady trong to\u00e0n b\u1ed9 quy tr\u00ecnh ph\u00e1t tri\u1ec3n? Vi\u1ec7c x\u00e2y d\u1ef1ng m\u1ed9t c\u1ea5u tr\u00fac d\u1eef li\u1ec7u m\u1ea1ch l\u1ea1c kh\u00f4ng ch\u1ec9 gi\u00fap \u0111\u1ed3ng b\u1ed9 gi\u1eefa c\u00e1c b\u1ed9 ph\u1eadn k\u1ef9 thu\u1eadt v\u00e0 nghi\u1ec7p v\u1ee5 m\u00e0 c\u00f2n t\u1ea1o ti\u1ec1n \u0111\u1ec1 cho kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng v\u00e0 b\u1ea3o tr\u00ec h\u1ec7 th\u1ed1ng v\u1ec1 sau.<\/strong><\/p>\n\n\n\n M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u (Data Modeling) l\u00e0 qu\u00e1 tr\u00ecnh ph\u00e2n t\u00edch v\u00e0 tr\u00ecnh b\u00e0y c\u1ea5u tr\u00fac d\u1eef li\u1ec7u m\u1ed9t c\u00e1ch c\u00f3 h\u1ec7 th\u1ed1ng v\u00e0 tr\u1ef1c quan, th\u01b0\u1eddng th\u00f4ng qua c\u00e1c s\u01a1 \u0111\u1ed3 ho\u1eb7c m\u00f4 h\u00ecnh bi\u1ec3u di\u1ec5n. M\u1ee5c ti\u00eau ch\u00ednh c\u1ee7a m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 m\u00f4 t\u1ea3 c\u00e1ch d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c, l\u01b0u tr\u1eef, li\u00ean k\u1ebft v\u00e0 s\u1eed d\u1ee5ng trong m\u1ed9t h\u1ec7 th\u1ed1ng th\u00f4ng tin ho\u1eb7c c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/strong><\/p>\n<\/blockquote>\n\n\n\n Th\u00f4ng qua m\u00f4 h\u00ecnh h\u00f3a, c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n, ph\u00e2n t\u00edch d\u1eef li\u1ec7u, ki\u1ebfn tr\u00fac s\u01b0 h\u1ec7 th\u1ed1ng v\u00e0 c\u00e1c b\u00ean li\u00ean quan c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng hi\u1ec3u \u0111\u01b0\u1ee3c lu\u1ed3ng d\u1eef li\u1ec7u, m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng trong h\u1ec7 th\u1ed1ng, c\u0169ng nh\u01b0 nh\u1eefng quy t\u1eafc v\u00e0 r\u00e0ng bu\u1ed9c li\u00ean quan \u0111\u1ebfn d\u1eef li\u1ec7u. Vi\u1ec7c n\u00e0y \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong vi\u1ec7c x\u00e2y d\u1ef1ng h\u1ec7 th\u1ed1ng hi\u1ec7u qu\u1ea3, d\u1ec5 b\u1ea3o tr\u00ec v\u00e0 c\u00f3 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng cao.<\/p>\n\n\n\n M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u th\u01b0\u1eddng l\u00e0 b\u01b0\u1edbc kh\u1edfi \u0111\u1ea7u trong qu\u00e1 tr\u00ecnh thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m ho\u1eb7c c\u01a1 s\u1edf d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o s\u1ef1 nh\u1ea5t qu\u00e1n gi\u1eefa nhu c\u1ea7u nghi\u1ec7p v\u1ee5 v\u00e0 c\u00e1ch tri\u1ec3n khai k\u1ef9 thu\u1eadt ph\u00eda sau.<\/p>\n\n\n\n M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u kh\u00f4ng ch\u1ec9 l\u00e0 m\u1ed9t b\u01b0\u1edbc k\u1ef9 thu\u1eadt trong qu\u00e1 tr\u00ecnh ph\u00e1t tri\u1ec3n h\u1ec7 th\u1ed1ng, m\u00e0 c\u00f2n l\u00e0 c\u1ea7u n\u1ed1i gi\u1eefa ng\u01b0\u1eddi ph\u00e2n t\u00edch nghi\u1ec7p v\u1ee5 v\u00e0 \u0111\u1ed9i ng\u0169 k\u1ef9 thu\u1eadt. Vi\u1ec7c x\u00e2y d\u1ef1ng m\u00f4 h\u00ecnh d\u1eef li\u1ec7u hi\u1ec7u qu\u1ea3 gi\u00fap ti\u1ebft ki\u1ec7m chi ph\u00ed, t\u1ed1i \u01b0u hi\u1ec7u su\u1ea5t v\u1eadn h\u00e0nh v\u00e0 n\u00e2ng cao ch\u1ea5t l\u01b0\u1ee3ng ra quy\u1ebft \u0111\u1ecbnh d\u1ef1a tr\u00ean d\u1eef li\u1ec7u.<\/p>\n\n\n\n M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u \u0111\u00f3ng vai tr\u00f2 n\u1ec1n t\u1ea3ng trong qu\u1ea3n l\u00fd d\u1eef li\u1ec7u, gi\u00fap t\u1ed5 ch\u1ee9c \u0111\u1ecbnh h\u00ecnh c\u00e1ch l\u01b0u tr\u1eef, truy xu\u1ea5t v\u00e0 ph\u00e2n t\u00edch th\u00f4ng tin m\u1ed9t c\u00e1ch logic, c\u00f3 h\u1ec7 th\u1ed1ng. Th\u00f4ng qua vi\u1ec7c x\u00e1c \u0111\u1ecbnh r\u00f5 c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7, m\u00f4 h\u00ecnh d\u1eef li\u1ec7u cho ph\u00e9p doanh nghi\u1ec7p:<\/p>\n\n\n\n Ngo\u00e0i ra, m\u00f4 h\u00ecnh d\u1eef li\u1ec7u c\u00f2n gi\u00fap ph\u00e1t hi\u1ec7n v\u00e0 lo\u1ea1i b\u1ecf c\u00e1c \u0111i\u1ec3m d\u01b0 th\u1eeba, m\u00e2u thu\u1eabn trong thi\u1ebft k\u1ebf ngay t\u1eeb giai \u0111o\u1ea1n \u0111\u1ea7u, t\u1eeb \u0111\u00f3 gi\u1ea3m thi\u1ec3u r\u1ee7i ro v\u1ec1 sau trong qu\u00e1 tr\u00ecnh v\u1eadn h\u00e0nh v\u00e0 ph\u00e2n t\u00edch.<\/p>\n\n\n\n Vi\u1ec7c m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u mang l\u1ea1i nhi\u1ec1u l\u1ee3i \u00edch thi\u1ebft th\u1ef1c cho t\u1ed5 ch\u1ee9c\/doanh nghi\u1ec7p, bao g\u1ed3m:<\/p>\n\n\n\n Trong qu\u00e1 tr\u00ecnh ph\u00e1t tri\u1ec3n h\u1ec7 th\u1ed1ng, m\u00f4 h\u00ecnh d\u1eef li\u1ec7u th\u01b0\u1eddng \u0111\u01b0\u1ee3c chia th\u00e0nh ba c\u1ea5p \u0111\u1ed9: kh\u00e1i ni\u1ec7m, logic v\u00e0 v\u1eadt l\u00fd. M\u1ed7i c\u1ea5p \u0111\u1ed9 th\u1ec3 hi\u1ec7n d\u1eef li\u1ec7u \u1edf m\u1ed9t m\u1ee9c \u0111\u1ed9 tr\u1eebu t\u01b0\u1ee3ng kh\u00e1c nhau, ph\u1ee5c v\u1ee5 c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng s\u1eed d\u1ee5ng kh\u00e1c nhau \u2014 t\u1eeb nh\u00e0 ph\u00e2n t\u00edch nghi\u1ec7p v\u1ee5 \u0111\u1ebfn k\u1ef9 s\u01b0 c\u01a1 s\u1edf d\u1eef li\u1ec7u. Vi\u1ec7c hi\u1ec3u r\u00f5 ba lo\u1ea1i m\u00f4 h\u00ecnh n\u00e0y gi\u00fap \u0111\u1ea3m b\u1ea3o thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng d\u1eef li\u1ec7u m\u1ea1ch l\u1ea1c, th\u1ed1ng nh\u1ea5t v\u00e0 d\u1ec5 tri\u1ec3n khai.<\/p>\n\n\n\n \u0110\u00e2y l\u00e0 c\u1ea5p \u0111\u1ed9 cao nh\u1ea5t trong m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u, t\u1eadp trung v\u00e0o vi\u1ec7c m\u00f4 t\u1ea3 c\u00e1c th\u1ef1c th\u1ec3 ch\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang<\/strong> trong m\u1ed9t h\u1ec7 th\u1ed1ng m\u00e0 kh\u00f4ng \u0111i s\u00e2u v\u00e0o chi ti\u1ebft k\u1ef9 thu\u1eadt.<\/p>\n\n\n\n \u0110\u1eb7c \u0111i\u1ec3m:<\/p>\n\n\n\n V\u00ed d\u1ee5: Trong h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd sinh vi\u00ean, m\u00f4 h\u00ecnh kh\u00e1i ni\u1ec7m ch\u1ec9 ra r\u1eb1ng “Sinh vi\u00ean” \u0111\u0103ng k\u00fd “L\u1edbp h\u1ecdc” v\u00e0 \u0111\u01b0\u1ee3c gi\u1ea3ng d\u1ea1y b\u1edfi “Gi\u1ea3ng vi\u00ean”, m\u00e0 kh\u00f4ng m\u00f4 t\u1ea3 c\u00e1c chi ti\u1ebft nh\u01b0 s\u1ed1 \u0111i\u1ec7n tho\u1ea1i, m\u00e3 l\u1edbp,…<\/p>\n\n\n\n M\u00f4 h\u00ecnh logic c\u1ee5 th\u1ec3 h\u01a1n m\u00f4 h\u00ecnh kh\u00e1i ni\u1ec7m, \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng d\u1ef1a tr\u00ean y\u00eau c\u1ea7u nghi\u1ec7p v\u1ee5 v\u00e0 m\u00f4 t\u1ea3 chi ti\u1ebft c\u00e1c thu\u1ed9c t\u00ednh, ki\u1ec3u d\u1eef li\u1ec7u, r\u00e0ng bu\u1ed9c<\/strong> nh\u01b0ng v\u1eabn \u0111\u1ed9c l\u1eadp v\u1edbi n\u1ec1n t\u1ea3ng c\u01a1 s\u1edf d\u1eef li\u1ec7u c\u1ee5 th\u1ec3.<\/p>\n\n\n\n \u0110\u1eb7c \u0111i\u1ec3m:<\/p>\n\n\n\n V\u00ed d\u1ee5: B\u1ea3ng “SinhVien” c\u00f3 c\u00e1c thu\u1ed9c t\u00ednh nh\u01b0 MaSV, HoTen, NgaySinh, LopID; trong \u0111\u00f3 MaSV l\u00e0 kh\u00f3a ch\u00ednh, LopID l\u00e0 kh\u00f3a ngo\u1ea1i tham chi\u1ebfu \u0111\u1ebfn b\u1ea3ng “Lop”.<\/p>\n\n\n\n \u0110\u00e2y l\u00e0 c\u1ea5p \u0111\u1ed9 chi ti\u1ebft nh\u1ea5t, m\u00f4 t\u1ea3 c\u00e1ch d\u1eef li\u1ec7u s\u1ebd \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef th\u1ef1c t\u1ebf trong h\u1ec7 qu\u1ea3n tr\u1ecb c\u01a1 s\u1edf d\u1eef li\u1ec7u<\/strong> \u0111\u00e3 ch\u1ecdn (nh\u01b0 MySQL, Oracle, SQL Server,…).<\/p>\n\n\n\n \u0110\u1eb7c \u0111i\u1ec3m:<\/p>\n\n\n\n V\u00ed d\u1ee5: Tr\u01b0\u1eddng MaSV \u0111\u01b0\u1ee3c khai b\u00e1o l\u00e0 VARCHAR(10) NOT NULL PRIMARY KEY, NgaySinh l\u00e0 DATE, c\u00f3 th\u00eam ch\u1ec9 m\u1ee5c cho c\u1ed9t HoTen \u0111\u1ec3 t\u0103ng t\u1ed1c t\u00ecm ki\u1ebfm.<\/p>\n\n\n\n Quy tr\u00ecnh m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u kh\u00f4ng ch\u1ec9 \u0111\u01a1n thu\u1ea7n l\u00e0 v\u1ebd s\u01a1 \u0111\u1ed3, m\u00e0 l\u00e0 m\u1ed9t chu\u1ed7i c\u00e1c b\u01b0\u1edbc c\u00f3 h\u1ec7 th\u1ed1ng gi\u00fap \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf ch\u00ednh x\u00e1c, d\u1ec5 hi\u1ec3u v\u00e0 ph\u00f9 h\u1ee3p v\u1edbi nhu c\u1ea7u th\u1ef1c t\u1ebf c\u1ee7a t\u1ed5 ch\u1ee9c. M\u1ed9t quy tr\u00ecnh t\u1ed1t s\u1ebd gi\u00fap gi\u1ea3m thi\u1ec3u r\u1ee7i ro sai s\u00f3t khi tri\u1ec3n khai h\u1ec7 th\u1ed1ng v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh m\u1edf r\u1ed9ng, b\u1ea3o tr\u00ec l\u00e2u d\u00e0i.<\/p>\n\n\n\n Tr\u01b0\u1edbc khi b\u1eaft tay v\u00e0o thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, \u0111i\u1ec1u quan tr\u1ecdng nh\u1ea5t l\u00e0 ph\u1ea3i hi\u1ec3u r\u00f5 nhu c\u1ea7u c\u1ee7a doanh nghi\u1ec7p ho\u1eb7c ng\u01b0\u1eddi d\u00f9ng cu\u1ed1i. Giai \u0111o\u1ea1n n\u00e0y bao g\u1ed3m:<\/p>\n\n\n\n K\u1ebft qu\u1ea3 thu \u0111\u01b0\u1ee3c t\u1eeb b\u01b0\u1edbc n\u00e0y s\u1ebd l\u00e0 c\u01a1 s\u1edf \u0111\u1ec3 x\u00e2y d\u1ef1ng m\u00f4 h\u00ecnh ch\u00ednh x\u00e1c v\u00e0 ph\u00f9 h\u1ee3p th\u1ef1c ti\u1ec5n.<\/p>\n\n\n\n Sau khi \u0111\u00e3 c\u00f3 y\u00eau c\u1ea7u, b\u01b0\u1edbc ti\u1ebfp theo l\u00e0 x\u00e1c \u0111\u1ecbnh c\u00e1c th\u1ef1c th\u1ec3 (entities)<\/strong> \u2013 t\u1ee9c nh\u1eefng \u0111\u1ed1i t\u01b0\u1ee3ng ch\u00ednh trong h\u1ec7 th\u1ed1ng c\u1ea7n \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef th\u00f4ng tin, v\u00ed d\u1ee5 nh\u01b0 Kh\u00e1ch h\u00e0ng<\/em>, S\u1ea3n ph\u1ea9m<\/em>, \u0110\u01a1n h\u00e0ng<\/em>,…<\/p>\n\n\n\n Ti\u1ebfp theo l\u00e0 x\u00e1c \u0111\u1ecbnh m\u1ed1i quan h\u1ec7 (relationships)<\/strong> gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3. V\u00ed d\u1ee5: M\u1ed7i \u0111\u01a1n h\u00e0ng thu\u1ed9c v\u1ec1 m\u1ed9t kh\u00e1ch h\u00e0ng<\/em>, ho\u1eb7c m\u1ed7i s\u1ea3n ph\u1ea9m c\u00f3 th\u1ec3 n\u1eb1m trong nhi\u1ec1u \u0111\u01a1n h\u00e0ng<\/em> (m\u1ed1i quan h\u1ec7 nhi\u1ec1u-nhi\u1ec1u).<\/p>\n\n\n\n Giai \u0111o\u1ea1n n\u00e0y gi\u00fap h\u00ecnh th\u00e0nh c\u00e1i nh\u00ecn t\u1ed5ng th\u1ec3 v\u1ec1 h\u1ec7 th\u1ed1ng v\u00e0 l\u00e0 n\u1ec1n t\u1ea3ng \u0111\u1ec3 v\u1ebd s\u01a1 \u0111\u1ed3 m\u00f4 h\u00ecnh kh\u00e1i ni\u1ec7m.<\/p>\n\n\n\n T\u1eeb c\u00e1c th\u1ef1c th\u1ec3 v\u00e0 m\u1ed1i quan h\u1ec7 \u0111\u00e3 x\u00e1c \u0111\u1ecbnh, nh\u00f3m thi\u1ebft k\u1ebf s\u1ebd t\u1ea1o ra s\u01a1 \u0111\u1ed3 ERD (Entity-Relationship Diagram)<\/strong> \u2013 bi\u1ec3u di\u1ec5n tr\u1ef1c quan c\u1ea5u tr\u00fac d\u1eef li\u1ec7u d\u01b0\u1edbi d\u1ea1ng h\u00ecnh \u1ea3nh.<\/p>\n\n\n\n Trong ERD, m\u1ed7i th\u1ef1c th\u1ec3 s\u1ebd \u0111\u01b0\u1ee3c th\u1ec3 hi\u1ec7n d\u01b0\u1edbi d\u1ea1ng m\u1ed9t \u00f4 ch\u1ee9a t\u00ean v\u00e0 danh s\u00e1ch c\u00e1c thu\u1ed9c t\u00ednh ch\u00ednh. C\u00e1c m\u1ed1i quan h\u1ec7 s\u1ebd \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n b\u1eb1ng c\u00e1c \u0111\u01b0\u1eddng n\u1ed1i gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3, k\u00e8m theo ch\u00fa th\u00edch m\u00f4 t\u1ea3 lo\u1ea1i quan h\u1ec7 (1-1, 1-nhi\u1ec1u, nhi\u1ec1u-nhi\u1ec1u).<\/p>\n\n\n\n Vi\u1ec7c c\u00f3 m\u1ed9t m\u00f4 h\u00ecnh kh\u00e1i ni\u1ec7m r\u00f5 r\u00e0ng s\u1ebd gi\u00fap c\u00e1c b\u00ean li\u00ean quan d\u1ec5 d\u00e0ng \u0111\u00f3ng g\u00f3p \u00fd ki\u1ebfn v\u00e0 \u0111\u1ea3m b\u1ea3o h\u1ec7 th\u1ed1ng \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u00fang h\u01b0\u1edbng ngay t\u1eeb \u0111\u1ea7u.<\/p>\n\n\n\n Sau khi m\u00f4 h\u00ecnh kh\u00e1i ni\u1ec7m \u0111\u01b0\u1ee3c duy\u1ec7t, nh\u00f3m ph\u00e1t tri\u1ec3n s\u1ebd chuy\u1ec3n sang thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh logic. \u0110\u00e2y l\u00e0 n\u01a1i c\u00e1c th\u1ef1c th\u1ec3 \u0111\u01b0\u1ee3c chuy\u1ec3n th\u00e0nh b\u1ea3ng d\u1eef li\u1ec7u (tables), thu\u1ed9c t\u00ednh th\u00e0nh c\u00e1c c\u1ed9t (columns), v\u00e0 c\u00e1c quy t\u1eafc nh\u01b0:<\/p>\n\n\n\n M\u00f4 h\u00ecnh logic gi\u00fap \u0111\u1ea3m b\u1ea3o h\u1ec7 th\u1ed1ng d\u1eef li\u1ec7u kh\u00f4ng b\u1ecb d\u01b0 th\u1eeba, d\u1ec5 m\u1edf r\u1ed9ng v\u00e0 ph\u00f9 h\u1ee3p v\u1edbi quy tr\u00ecnh nghi\u1ec7p v\u1ee5 \u0111\u00e3 x\u00e1c \u0111\u1ecbnh t\u1eeb \u0111\u1ea7u.<\/p>\n\n\n\n B\u01b0\u1edbc cu\u1ed1i c\u00f9ng l\u00e0 chuy\u1ec3n m\u00f4 h\u00ecnh logic sang d\u1ea1ng c\u1ee5 th\u1ec3 \u0111\u1ec3 tri\u1ec3n khai tr\u00ean h\u1ec7 qu\u1ea3n tr\u1ecb c\u01a1 s\u1edf d\u1eef li\u1ec7u (DBMS). \u1ede b\u01b0\u1edbc n\u00e0y, k\u1ef9 s\u01b0 d\u1eef li\u1ec7u s\u1ebd l\u1ef1a ch\u1ecdn:<\/p>\n\n\n\n \u0110\u1ec3 qu\u00e1 tr\u00ecnh thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh d\u1eef li\u1ec7u di\u1ec5n ra nhanh ch\u00f3ng, ch\u00ednh x\u00e1c v\u00e0 d\u1ec5 qu\u1ea3n l\u00fd, c\u00e1c chuy\u00ean gia th\u01b0\u1eddng s\u1eed d\u1ee5ng nh\u1eefng c\u00f4ng c\u1ee5 ph\u1ea7n m\u1ec1m chuy\u00ean bi\u1ec7t. C\u00e1c c\u00f4ng c\u1ee5 n\u00e0y h\u1ed7 tr\u1ee3 tr\u1ef1c quan h\u00f3a m\u00f4 h\u00ecnh, ki\u1ec3m tra logic d\u1eef li\u1ec7u v\u00e0 th\u1eadm ch\u00ed c\u00f3 th\u1ec3 t\u1ef1 \u0111\u1ed9ng sinh m\u00e3 l\u1ec7nh SQL t\u1eeb s\u01a1 \u0111\u1ed3.<\/p>\n\n\n\n T\u00f9y v\u00e0o quy m\u00f4 d\u1ef1 \u00e1n, ng\u00e2n s\u00e1ch, h\u1ec7 qu\u1ea3n tr\u1ecb c\u01a1 s\u1edf d\u1eef li\u1ec7u s\u1eed d\u1ee5ng, ng\u01b0\u1eddi d\u00f9ng c\u00f3 th\u1ec3 l\u1ef1a ch\u1ecdn c\u00f4ng c\u1ee5 mi\u1ec5n ph\u00ed ho\u1eb7c b\u1ea3n quy\u1ec1n tr\u1ea3 ph\u00ed ph\u00f9 h\u1ee3p v\u1edbi nhu c\u1ea7u.<\/p>\n\n\n\n C\u00e1c c\u00f4ng c\u1ee5 m\u00f4 h\u00ecnh h\u00f3a tr\u1ef1c quan gi\u00fap ng\u01b0\u1eddi d\u00f9ng d\u1ec5 d\u00e0ng t\u1ea1o s\u01a1 \u0111\u1ed3 ERD b\u1eb1ng thao t\u00e1c k\u00e9o \u2013 th\u1ea3. M\u1ed9t s\u1ed1 ph\u1ea7n m\u1ec1m c\u00f2n h\u1ed7 tr\u1ee3 c\u1ed9ng t\u00e1c nh\u00f3m, l\u01b0u tr\u1eef tr\u00ean \u0111\u00e1m m\u00e2y v\u00e0 \u0111\u1ed3ng b\u1ed9 h\u00f3a thay \u0111\u1ed5i theo th\u1eddi gian th\u1ef1c. C\u00e1c ph\u1ea7n m\u1ec1m n\u1ed5i b\u1eadt:<\/p>\n\n\n\n \u01afu \u0111i\u1ec3m c\u1ee7a nh\u00f3m c\u00f4ng c\u1ee5 n\u00e0y l\u00e0 d\u1ec5 s\u1eed d\u1ee5ng, kh\u00f4ng y\u00eau c\u1ea7u c\u00e0i \u0111\u1eb7t ph\u1ee9c t\u1ea1p v\u00e0 ph\u00f9 h\u1ee3p v\u1edbi h\u1ea7u h\u1ebft c\u00e1c b\u01b0\u1edbc trong quy tr\u00ecnh m\u00f4 h\u00ecnh h\u00f3a kh\u00e1i ni\u1ec7m v\u00e0 logic.<\/p>\n\n\n\n V\u1edbi c\u00e1c d\u1ef1 \u00e1n l\u1edbn ho\u1eb7c y\u00eau c\u1ea7u k\u1ef9 thu\u1eadt cao, nh\u00f3m c\u00f4ng c\u1ee5 chuy\u00ean s\u00e2u cho ph\u00e9p ng\u01b0\u1eddi d\u00f9ng thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh logic v\u00e0 v\u1eadt l\u00fd, ki\u1ec3m tra r\u00e0ng bu\u1ed9c d\u1eef li\u1ec7u, sinh m\u00e3 SQL, v\u00e0 k\u1ebft n\u1ed1i tr\u1ef1c ti\u1ebfp v\u1edbi h\u1ec7 qu\u1ea3n tr\u1ecb c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 tri\u1ec3n khai m\u00f4 h\u00ecnh.<\/p>\n\n\n\n M\u1ed9t s\u1ed1 c\u00f4ng c\u1ee5 ti\u00eau bi\u1ec3u:<\/p>\n\n\n\n Vi\u1ec7c tham kh\u1ea3o c\u00e1c m\u00f4 h\u00ecnh d\u1eef li\u1ec7u th\u1ef1c t\u1ebf s\u1ebd gi\u00fap b\u1ea1n h\u00ecnh dung r\u00f5 h\u01a1n c\u00e1ch l\u00fd thuy\u1ebft \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng v\u00e0o c\u00e1c h\u1ec7 th\u1ed1ng c\u1ee5 th\u1ec3. M\u1ed7i l\u0129nh v\u1ef1c ho\u1eb7c lo\u1ea1i h\u1ec7 th\u1ed1ng s\u1ebd c\u00f3 nh\u1eefng \u0111\u1eb7c \u0111i\u1ec3m d\u1eef li\u1ec7u ri\u00eang bi\u1ec7t, \u0111\u00f2i h\u1ecfi m\u00f4 h\u00ecnh h\u00f3a ph\u00f9 h\u1ee3p \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o ho\u1ea1t \u0111\u1ed9ng hi\u1ec7u qu\u1ea3 v\u00e0 \u0111\u00e1p \u1ee9ng nhu c\u1ea7u khai th\u00e1c th\u00f4ng tin.<\/p>\n\n\n\n Trong h\u1ec7 th\u1ed1ng b\u00e1n h\u00e0ng, c\u00e1c th\u1ef1c th\u1ec3 ch\u00ednh th\u01b0\u1eddng bao g\u1ed3m:<\/p>\n\n\n\n M\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3:<\/p>\n\n\n\n M\u00f4 h\u00ecnh n\u00e0y gi\u00fap doanh nghi\u1ec7p theo d\u00f5i l\u1ecbch s\u1eed mua h\u00e0ng, qu\u1ea3n l\u00fd t\u1ed3n kho v\u00e0 h\u1ed7 tr\u1ee3 ph\u00e2n t\u00edch h\u00e0nh vi kh\u00e1ch h\u00e0ng.<\/p>\n\n\n\n Trong h\u1ec7 th\u1ed1ng HRM (Human Resource Management), m\u1ed9t s\u1ed1 th\u1ef1c th\u1ec3 th\u01b0\u1eddng g\u1eb7p:<\/p>\n\n\n\n Quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3:<\/p>\n\n\n\n M\u00f4 h\u00ecnh n\u00e0y h\u1ed7 tr\u1ee3 t\u1ef1 \u0111\u1ed9ng h\u00f3a quy tr\u00ecnh t\u00ednh l\u01b0\u01a1ng, theo d\u00f5i hi\u1ec7u su\u1ea5t l\u00e0m vi\u1ec7c v\u00e0 l\u1eadp b\u00e1o c\u00e1o n\u1ed9i b\u1ed9.<\/p>\n\n\n\n \u0110\u1ed1i v\u1edbi h\u1ec7 th\u1ed1ng \u0111\u00e0o t\u1ea1o tr\u1ef1c tuy\u1ebfn, m\u00f4 h\u00ecnh d\u1eef li\u1ec7u th\u01b0\u1eddng g\u1ed3m:<\/p>\n\n\n\n M\u1ed1i quan h\u1ec7:<\/p>\n\n\n\n M\u00f4 h\u00ecnh n\u00e0y gi\u00fap h\u1ec7 th\u1ed1ng c\u00e1 nh\u00e2n h\u00f3a h\u00e0nh tr\u00ecnh h\u1ecdc, theo d\u00f5i k\u1ebft qu\u1ea3, v\u00e0 c\u1ea3i thi\u1ec7n tr\u1ea3i nghi\u1ec7m h\u1ecdc t\u1eadp.<\/p>\n\n\n\n M\u1ed9t h\u1ec7 th\u1ed1ng ng\u00e2n h\u00e0ng s\u1ebd c\u00f3 c\u1ea5u tr\u00fac d\u1eef li\u1ec7u ph\u1ee9c t\u1ea1p h\u01a1n v\u1edbi c\u00e1c th\u1ef1c th\u1ec3:<\/p>\n\n\n\n Quan h\u1ec7 \u0111i\u1ec3n h\u00ecnh:<\/p>\n\n\n\n M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 c\u00f4ng vi\u1ec7c \u0111\u00f2i h\u1ecfi s\u1ef1 k\u1ebft h\u1ee3p gi\u1eefa t\u01b0 duy ph\u00e2n t\u00edch, kh\u1ea3 n\u0103ng n\u1eafm b\u1eaft nghi\u1ec7p v\u1ee5 v\u00e0 k\u1ef9 thu\u1eadt tri\u1ec3n khai. Tuy nhi\u00ean, ngay c\u1ea3 nh\u1eefng ng\u01b0\u1eddi c\u00f3 kinh nghi\u1ec7m c\u0169ng c\u00f3 th\u1ec3 m\u1eafc ph\u1ea3i nh\u1eefng sai s\u00f3t ph\u1ed5 bi\u1ebfn n\u1ebfu kh\u00f4ng c\u1ea9n tr\u1ecdng. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 l\u01b0u \u00fd quan tr\u1ecdng v\u00e0 l\u1ed7i th\u01b0\u1eddng g\u1eb7p c\u1ea7n tr\u00e1nh \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o m\u00f4 h\u00ecnh d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng hi\u1ec7u qu\u1ea3 v\u00e0 b\u1ec1n v\u1eefng.<\/p>\n\n\n\n Sai l\u1ea7m ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0 lao v\u00e0o thi\u1ebft k\u1ebf khi ch\u01b0a hi\u1ec3u r\u00f5 y\u00eau c\u1ea7u c\u1ee7a ng\u01b0\u1eddi d\u00f9ng cu\u1ed1i ho\u1eb7c quy tr\u00ecnh nghi\u1ec7p v\u1ee5 th\u1ef1c t\u1ebf. Vi\u1ec7c thi\u1ebfu th\u00f4ng tin \u0111\u1ea7u v\u00e0o s\u1ebd d\u1eabn \u0111\u1ebfn:<\/p>\n\n\n\n ? L\u01b0u \u00fd<\/strong>: Lu\u00f4n d\u00e0nh \u0111\u1ee7 th\u1eddi gian \u0111\u1ec3 trao \u0111\u1ed5i, kh\u1ea3o s\u00e1t v\u00e0 x\u00e1c minh y\u00eau c\u1ea7u v\u1edbi c\u00e1c b\u00ean li\u00ean quan tr\u01b0\u1edbc khi b\u1eaft \u0111\u1ea7u x\u00e2y d\u1ef1ng m\u00f4 h\u00ecnh.<\/p>\n\n\n\n Chu\u1ea9n h\u00f3a l\u00e0 b\u01b0\u1edbc quan tr\u1ecdng \u0111\u1ec3 tr\u00e1nh tr\u00f9ng l\u1eb7p d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o t\u00ednh nh\u1ea5t qu\u00e1n. Tuy nhi\u00ean:<\/p>\n\n\n\n ? L\u01b0u \u00fd<\/strong>: N\u00ean chu\u1ea9n h\u00f3a d\u1eef li\u1ec7u h\u1ee3p l\u00fd \u0111\u1ebfn c\u1ea5p \u0111\u1ed9 3NF l\u00e0 \u0111\u1ee7 cho ph\u1ea7n l\u1edbn h\u1ec7 th\u1ed1ng th\u00f4ng th\u01b0\u1eddng. Trong m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p th\u1ef1c t\u1ebf, c\u00f3 th\u1ec3 c\u00e2n nh\u1eafc phi chu\u1ea9n h\u00f3a<\/strong> c\u00f3 ki\u1ec3m so\u00e1t \u0111\u1ec3 t\u1ed1i \u01b0u hi\u1ec7u n\u0103ng.<\/p>\n\n\n\n M\u1ed9t l\u1ed7i nghi\u00eam tr\u1ecdng kh\u00e1c l\u00e0 kh\u00f4ng x\u00e1c \u0111\u1ecbnh v\u00e0 th\u1ec3 hi\u1ec7n r\u00f5 c\u00e1c r\u00e0ng bu\u1ed9c v\u1ec1 d\u1eef li\u1ec7u nh\u01b0:<\/p>\n\n\n\n Vi\u1ec7c thi\u1ebfu c\u00e1c r\u00e0ng bu\u1ed9c s\u1ebd d\u1eabn \u0111\u1ebfn kh\u1ea3 n\u0103ng nh\u1eadp sai d\u1eef li\u1ec7u, \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn to\u00e0n b\u1ed9 h\u1ec7 th\u1ed1ng ph\u00e2n t\u00edch v\u00e0 b\u00e1o c\u00e1o sau n\u00e0y.<\/p>\n\n\n\n ? L\u01b0u \u00fd<\/strong>: Trong m\u00f4 h\u00ecnh logic v\u00e0 v\u1eadt l\u00fd, c\u1ea7n th\u1ec3 hi\u1ec7n \u0111\u1ea7y \u0111\u1ee7 c\u00e1c r\u00e0ng bu\u1ed9c n\u00e0y \u0111\u1ec3 gi\u00fap h\u1ec7 th\u1ed1ng t\u1ef1 \u0111\u1ed9ng ki\u1ec3m tra t\u00ednh h\u1ee3p l\u1ec7 c\u1ee7a d\u1eef li\u1ec7u.<\/p>\n\n\n\n Vi\u1ec7c x\u00e2y d\u1ef1ng h\u1ec7 th\u1ed1ng hi\u1ec7u qu\u1ea3 kh\u00f4ng th\u1ec3 t\u00e1ch r\u1eddi m\u1ed9t n\u1ec1n t\u1ea3ng d\u1eef li\u1ec7u v\u1eefng ch\u1eafc. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 g\u00ec<\/strong> \u0111\u00e3 kh\u00f4ng c\u00f2n l\u00e0 c\u00e2u h\u1ecfi c\u1ee7a ri\u00eang gi\u1edbi k\u1ef9 thu\u1eadt m\u00e0 tr\u1edf th\u00e0nh m\u1ed1i quan t\u00e2m chung c\u1ee7a nhi\u1ec1u b\u1ed9 ph\u1eadn trong doanh nghi\u1ec7p. Khi \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n \u0111\u00fang c\u00e1ch, m\u00f4 h\u00ecnh h\u00f3a gi\u00fap k\u1ebft n\u1ed1i nhu c\u1ea7u th\u1ef1c t\u1ebf v\u1edbi gi\u1ea3i ph\u00e1p c\u00f4ng ngh\u1ec7, t\u1ea1o n\u00ean h\u1ec7 th\u1ed1ng nh\u1ea5t qu\u00e1n, linh ho\u1ea1t v\u00e0 d\u1ec5 m\u1edf r\u1ed9ng. C\u1ea3m \u01a1n c\u00e1c b\u1ea1n \u0111\u00e3 theo d\u00f5i b\u00e0i vi\u1ebft Careerlink.vn<\/strong>.<\/p>\n\n\n\n Tr\u00ed Nh\u00e2n<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":" Thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng th\u00f4ng tin hi\u1ec7u qu\u1ea3 lu\u00f4n \u0111\u00f2i h\u1ecfi s\u1ef1 hi\u1ec3u bi\u1ebft r\u00f5 r\u00e0ng v\u1ec1 c\u00e1ch d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c t\u1ed5 ch\u1ee9c v\u00e0 v\u1eadn …<\/p>\n","protected":false},"author":58,"featured_media":9290,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[64],"class_list":["post-9289","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tu-van-nghe-nghiep","tag-it"],"_links":{"self":[{"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/posts\/9289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/users\/58"}],"replies":[{"embeddable":true,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/comments?post=9289"}],"version-history":[{"count":1,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/posts\/9289\/revisions"}],"predecessor-version":[{"id":9291,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/posts\/9289\/revisions\/9291"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/media\/9290"}],"wp:attachment":[{"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/media?parent=9289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/categories?post=9289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mb668s.com\/cam-nang-7mb66-xoc-dia\/wp-json\/wp\/v2\/tags?post=9289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/figure>\n\n\n\nM\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u l\u00e0 g\u00ec?<\/h2>\n\n\n\n
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Vai tr\u00f2 v\u00e0 l\u1ee3i \u00edch c\u1ee7a m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u<\/h2>\n\n\n\n
Vai tr\u00f2 trong qu\u1ea3n l\u00fd v\u00e0 ph\u00e2n t\u00edch d\u1eef li\u1ec7u<\/h3>\n\n\n\n
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L\u1ee3i \u00edch \u0111\u1ed1i v\u1edbi t\u1ed5 ch\u1ee9c\/doanh nghi\u1ec7p<\/h3>\n\n\n\n
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C\u00e1c lo\u1ea1i m\u00f4 h\u00ecnh d\u1eef li\u1ec7u ph\u1ed5 bi\u1ebfn<\/h2>\n\n\n\n
M\u00f4 h\u00ecnh d\u1eef li\u1ec7u kh\u00e1i ni\u1ec7m (Conceptual Data Model)<\/h3>\n\n\n\n
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M\u00f4 h\u00ecnh d\u1eef li\u1ec7u logic (Logical Data Model)<\/h3>\n\n\n\n
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M\u00f4 h\u00ecnh d\u1eef li\u1ec7u v\u1eadt l\u00fd (Physical Data Model)<\/h3>\n\n\n\n
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Quy tr\u00ecnh m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u<\/h2>\n\n\n\n
Thu th\u1eadp v\u00e0 ph\u00e2n t\u00edch y\u00eau c\u1ea7u<\/h3>\n\n\n\n
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X\u00e1c \u0111\u1ecbnh th\u1ef1c th\u1ec3 v\u00e0 m\u1ed1i quan h\u1ec7<\/h3>\n\n\n\n
Thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh d\u1eef li\u1ec7u kh\u00e1i ni\u1ec7m (ERD)<\/h3>\n\n\n\n
Thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh d\u1eef li\u1ec7u logic<\/h3>\n\n\n\n
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Thi\u1ebft k\u1ebf m\u00f4 h\u00ecnh d\u1eef li\u1ec7u v\u1eadt l\u00fd<\/h3>\n\n\n\n
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C\u00e1c c\u00f4ng c\u1ee5 h\u1ed7 tr\u1ee3 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u<\/h2>\n\n\n\n
C\u00f4ng c\u1ee5 m\u00f4 h\u00ecnh h\u00f3a tr\u1ef1c quan (visual modeling tools)<\/h3>\n\n\n\n
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C\u00f4ng c\u1ee5 chuy\u00ean s\u00e2u v\u00e0 t\u00edch h\u1ee3p v\u1edbi h\u1ec7 qu\u1ea3n tr\u1ecb c\u01a1 s\u1edf d\u1eef li\u1ec7u (DBMS)<\/h3>\n\n\n\n
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M\u1ed9t s\u1ed1 v\u00ed d\u1ee5 v\u1ec1 m\u00f4 h\u00ecnh d\u1eef li\u1ec7u ph\u1ed5 bi\u1ebfn trong th\u1ef1c t\u1ebf<\/h2>\n\n\n\n
M\u00f4 h\u00ecnh d\u1eef li\u1ec7u h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd b\u00e1n h\u00e0ng<\/h3>\n\n\n\n
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M\u00f4 h\u00ecnh d\u1eef li\u1ec7u h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd nh\u00e2n s\u1ef1<\/h3>\n\n\n\n
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M\u00f4 h\u00ecnh d\u1eef li\u1ec7u h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd h\u1ecdc t\u1eadp (E-learning)<\/h3>\n\n\n\n
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M\u00f4 h\u00ecnh d\u1eef li\u1ec7u h\u1ec7 th\u1ed1ng ng\u00e2n h\u00e0ng<\/h3>\n\n\n\n
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Nh\u1eefng l\u01b0u \u00fd v\u00e0 sai l\u1ea7m th\u01b0\u1eddng g\u1eb7p khi m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u<\/h2>\n\n\n\n
Kh\u00f4ng x\u00e1c \u0111\u1ecbnh \u0111\u00fang y\u00eau c\u1ea7u nghi\u1ec7p v\u1ee5<\/h3>\n\n\n\n
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Thi\u1ebfu chu\u1ea9n h\u00f3a d\u1eef li\u1ec7u ho\u1eb7c chu\u1ea9n h\u00f3a qu\u00e1 m\u1ee9c<\/h3>\n\n\n\n
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B\u1ecf qua c\u00e1c r\u00e0ng bu\u1ed9c d\u1eef li\u1ec7u v\u00e0 quy t\u1eafc nghi\u1ec7p v\u1ee5<\/h3>\n\n\n\n
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