{"id":6546,"date":"2026-02-05T09:40:38","date_gmt":"2026-02-05T01:40:38","guid":{"rendered":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/"},"modified":"2026-02-05T09:40:38","modified_gmt":"2026-02-05T01:40:38","slug":"class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide","status":"publish","type":"post","link":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/","title":{"rendered":"S\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh"},"content":{"rendered":"

Gi\u1edbi thi\u1ec7u<\/h2>\n

S\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) l\u00e0 hai c\u00f4ng c\u1ee5 thi\u1ebft y\u1ebfu trong thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u. M\u1eb7c d\u00f9 ch\u00fang c\u00f3 m\u1ed9t s\u1ed1 \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng, nh\u01b0ng ch\u00fang ph\u1ee5c v\u1ee5 c\u00e1c m\u1ee5c \u0111\u00edch kh\u00e1c nhau v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c b\u1ed1i c\u1ea3nh kh\u00e1c nhau. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang t\u00f4i s\u1ebd kh\u00e1m ph\u00e1 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai lo\u1ea1i s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u01b0a ra c\u00e1c v\u00ed d\u1ee5 v\u00e0 th\u1ea3o lu\u1eadn v\u1ec1 khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng t\u1eebng lo\u1ea1i.<\/p>\n

S\u01a1 \u0111\u1ed3 l\u1edbp<\/strong><\/h2>\n

M\u1ee5c \u0111\u00edch:<\/strong><\/h3>\n

S\u01a1 \u0111\u1ed3 l\u1edbp ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 thi\u1ebft k\u1ebf \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp v\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng trong m\u1ed9t h\u1ec7 th\u1ed1ng. \u0110\u00e2y l\u00e0 m\u1ed9t ph\u1ea7n thi\u1ebft y\u1ebfu c\u1ee7a Ng\u00f4n ng\u1eef m\u00f4 h\u00ecnh h\u00f3a th\u1ed1ng nh\u1ea5t (UML) v\u00e0 gi\u00fap h\u00ecnh dung c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a h\u1ec7 th\u1ed1ng.<\/p>\n

C\u00e1c th\u00e0nh ph\u1ea7n:<\/strong><\/h3>\n
    \n
  1. L\u1edbp:<\/strong>Bi\u1ec3u di\u1ec5n b\u1ea3n v\u1ebd m\u1eabu cho m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh (th\u00e0nh vi\u00ean d\u1eef li\u1ec7u) v\u00e0 ph\u01b0\u01a1ng th\u1ee9c (h\u00e0m).<\/li>\n
  2. Li\u00ean k\u1ebft:<\/strong>Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp, bao g\u1ed3m c\u00e1c li\u00ean k\u1ebft m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u.<\/li>\n
  3. K\u1ebf th\u1eeba:<\/strong>Minh h\u1ecda c\u1ea5u tr\u00fac k\u1ebf th\u1eeba, cho th\u1ea5y c\u00e1c l\u1edbp n\u00e0o k\u1ebf th\u1eeba t\u1eeb c\u00e1c l\u1edbp kh\u00e1c.<\/li>\n
  4. T\u1ed5ng h\u1ee3p v\u00e0 k\u1ebft h\u1ee3p:<\/strong>Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 to\u00e0n th\u1ec3-ph\u1ea7n, ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t chi\u1ebfc xe h\u01a1i v\u00e0 \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3.<\/li>\n
  5. Thu\u1ed9c t\u00ednh v\u00e0 thao t\u00e1c:<\/strong>Hi\u1ec3n th\u1ecb c\u00e1c thu\u1ed9c t\u00ednh (thu\u1ed9c t\u00ednh) v\u00e0 h\u00e0nh vi (ph\u01b0\u01a1ng th\u1ee9c) c\u1ee7a m\u1ed9t l\u1edbp.<\/li>\n<\/ol>\n

    V\u00ed d\u1ee5:<\/strong><\/h3>\n

    H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t v\u00ed d\u1ee5 \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 bi\u1ec3u di\u1ec5n m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0 vi\u1ec7n b\u1eb1ng s\u01a1 \u0111\u1ed3 l\u1edbp:<\/p>\n

    <\/p>\n

    Trong s\u01a1 \u0111\u1ed3 l\u1edbp n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c l\u1edbp nh\u01b0Th\u01b0 vi\u1ec7n<\/code>, S\u00e1ch<\/code>, v\u00e0T\u00e1c gi\u1ea3<\/code>, th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang.<\/p>\n

    S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD)<\/strong><\/h2>\n

    M\u1ee5c \u0111\u00edch:<\/strong><\/h3>\n

    S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 (b\u1ea3ng) trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. N\u00f3 t\u1eadp trung v\u00e0o vi\u1ec7c ghi l\u1ea1i m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7.<\/p>\n

    C\u00e1c th\u00e0nh ph\u1ea7n:<\/strong><\/h3>\n
      \n
    1. Th\u1ef1c th\u1ec3:<\/strong> \u0110\u1ea1i di\u1ec7n cho m\u1ed9t b\u1ea3ng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, th\u01b0\u1eddng t\u01b0\u01a1ng \u1ee9ng v\u1edbi c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c kh\u00e1i ni\u1ec7m trong th\u1ebf gi\u1edbi th\u1ef1c.<\/li>\n
    2. Thu\u1ed9c t\u00ednh:<\/strong> Th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh ho\u1eb7c tr\u01b0\u1eddng c\u1ee7a m\u1ed9t th\u1ef1c th\u1ec3.<\/li>\n
    3. M\u1ed1i quan h\u1ec7:<\/strong> Minh h\u1ecda c\u00e1ch c\u00e1c th\u1ef1c th\u1ec3 li\u00ean quan \u0111\u1ebfn nhau, bao g\u1ed3m c\u00e1c m\u1ed1i quan h\u1ec7 m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u.<\/li>\n
    4. Kh\u00f3a ch\u00ednh:<\/strong> X\u00e1c \u0111\u1ecbnh m\u1ed9t thu\u1ed9c t\u00ednh duy nh\u1ea5t ho\u1eb7c t\u1ed5 h\u1ee3p c\u00e1c thu\u1ed9c t\u00ednh gi\u00fap x\u00e1c \u0111\u1ecbnh duy nh\u1ea5t m\u1ed7i th\u1ef1c th\u1ec3.<\/li>\n
    5. Kh\u00f3a ngo\u1ea1i:<\/strong> \u0110\u1ea1i di\u1ec7n cho m\u1ed9t li\u00ean k\u1ebft gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n tham chi\u1ebfu trong c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n<\/ol>\n

      V\u00ed d\u1ee5:<\/strong><\/h3>\n

      H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t s\u01a1 \u0111\u1ed3 th\u1ef1c th\u1ec3 – m\u1ed1i quan h\u1ec7 cho m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed \u0111\u01a1n gi\u1ea3n:<\/p>\n

      <\/p>\n

      Trong s\u01a1 \u0111\u1ed3 n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c th\u1ef1c th\u1ec3 nh\u01b0Kh\u00e1ch h\u00e0ng<\/code>, \u0110\u01a1n h\u00e0ng<\/code>, v\u00e0S\u1ea3n ph\u1ea9m<\/code>, c\u00f9ng v\u1edbi c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. C\u00e1c kh\u00f3a ngo\u1ea1i (CustomerID<\/code>, ProductID<\/code>) thi\u1ebft l\u1eadp c\u00e1c k\u1ebft n\u1ed1i gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 n\u00e0y.<\/p>\n

      Khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng lo\u1ea1i n\u00e0o?<\/strong><\/h2>\n

      S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp khi:<\/strong><\/h3>\n
        \n
      1. Thi\u1ebft k\u1ebf c\u00e1c h\u1ec7 th\u1ed1ng h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng:<\/strong> N\u1ebfu b\u1ea1n \u0111ang l\u00e0m vi\u1ec7c tr\u00ean m\u1ed9t d\u1ef1 \u00e1n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u1ea7n bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang, h\u00e3y s\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp.<\/li>\n
      2. M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m:<\/strong> S\u01a1 \u0111\u1ed3 l\u1edbp h\u1eefu \u00edch \u0111\u1ec3 tr\u1ef1c quan h\u00f3a c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, bao g\u1ed3m c\u00e1c c\u1ea5p l\u1edbp, giao di\u1ec7n v\u00e0 c\u00e1c ph\u1ee5 thu\u1ed9c.<\/li>\n
      3. Thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c<\/strong>S\u01a1 \u0111\u1ed3 l\u1edbp th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c bu\u1ed5i thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c \u0111\u1ec3 h\u1ed7 tr\u1ee3 th\u1ea3o lu\u1eadn gi\u1eefa c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n, nh\u00e0 thi\u1ebft k\u1ebf v\u00e0 c\u00e1c b\u00ean li\u00ean quan.<\/li>\n<\/ol>\n

        S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 khi:<\/strong><\/h3>\n
          \n
        1. Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u:<\/strong>Khi thi\u1ebft k\u1ebf m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, h\u00e3y s\u1eed d\u1ee5ng ERD \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c b\u1ea3ng, c\u00e1c thu\u1ed9c t\u00ednh c\u1ee7a ch\u00fang v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang.<\/li>\n
        2. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u:<\/strong>ERD l\u00e0 thi\u1ebft y\u1ebfu cho vi\u1ec7c m\u00f4 h\u00ecnh h\u00f3a v\u00e0 hi\u1ec3u y\u00eau c\u1ea7u d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 t\u1ed5 ch\u1ee9c c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n
        3. T\u00e0i li\u1ec7u c\u01a1 s\u1edf d\u1eef li\u1ec7u:<\/strong>ERD \u0111\u00f3ng vai tr\u00f2 l\u00e0 t\u00e0i li\u1ec7u qu\u00fd gi\u00e1 cho c\u00e1c qu\u1ea3n tr\u1ecb vi\u00ean c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n, m\u00f4 t\u1ea3 c\u1ea5u tr\u00fac v\u00e0 c\u00e1c r\u00e0ng bu\u1ed9c c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/li>\n<\/ol>\n

          T\u00f3m t\u1eaft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD<\/h2>\n

          D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng so s\u00e1nh s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) \u1edf c\u00e1c kh\u00eda c\u1ea1nh kh\u00e1c nhau:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
          Kh\u00eda c\u1ea1nh<\/th>\nS\u01a1 \u0111\u1ed3 l\u1edbp<\/th>\nS\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD)<\/th>\n<\/tr>\n<\/thead>\n
          M\u1ee5c \u0111\u00edch<\/strong><\/td>\nBi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m.<\/td>\nBi\u1ec3u di\u1ec5n c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n
          C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng ch\u00ednh<\/strong><\/td>\n\u2013 Thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng<br>- M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m<\/td>\n\u2013 Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7<br>- M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u<\/td>\n<\/tr>\n
          C\u00e1c th\u00e0nh ph\u1ea7n<\/strong><\/td>\n\u2013 L\u1edbp<br>- Thu\u1ed9c t\u00ednh<br>- Ph\u01b0\u01a1ng th\u1ee9c (Thao t\u00e1c)<br>- Li\u00ean k\u1ebft<br>- K\u1ebf th\u1eeba<br>- T\u1ed5ng h\u1ee3p\/Th\u00e0nh ph\u1ea7n<\/td>\n\u2013 Th\u1ef1c th\u1ec3 (B\u1ea3ng)<br>- Thu\u1ed9c t\u00ednh (C\u1ed9t)<br>- M\u1ed1i quan h\u1ec7<br>- Kh\u00f3a ch\u00ednh<br>- Kh\u00f3a ngo\u1ea1i<\/td>\n<\/tr>\n
          S\u1ed1 l\u01b0\u1ee3ng<\/strong><\/td>\n\u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 th\u1ec3 hi\u1ec7n c\u00e1c li\u00ean k\u1ebft gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c l\u1edbp. C\u00f3 th\u1ec3 bi\u1ec3u di\u1ec5n t\u00ednh \u0111a d\u1ea1ng (v\u00ed d\u1ee5: m\u1ed9t-m\u1ed9t, m\u1ed9t-nhi\u1ec1u).<\/td>\n\u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 th\u1ec3 hi\u1ec7n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 trong c\u01a1 s\u1edf d\u1eef li\u1ec7u (v\u00ed d\u1ee5: m\u1ed9t-m\u1ed9t, m\u1ed9t-nhi\u1ec1u).<\/td>\n<\/tr>\n
          K\u00fd hi\u1ec7u<\/strong><\/td>\n\u2013 L\u1edbp v\u1edbi c\u00e1c ng\u0103n ch\u1ee9a thu\u1ed9c t\u00ednh v\u00e0 ph\u01b0\u01a1ng th\u1ee9c<br>- C\u00e1c \u0111\u01b0\u1eddng c\u00f3 m\u0169i t\u00ean \u0111\u1ec3 bi\u1ec3u di\u1ec5n li\u00ean k\u1ebft<\/td>\n\u2013 H\u00ecnh ch\u1eef nh\u1eadt cho th\u1ef1c th\u1ec3 (b\u1ea3ng)<br>- H\u00ecnh kim c\u01b0\u01a1ng cho m\u1ed1i quan h\u1ec7<br>- H\u00ecnh elip cho thu\u1ed9c t\u00ednh<\/td>\n<\/tr>\n
          Tr\u1ecdng t\u00e2m<\/strong><\/td>\nT\u1eadp trung v\u00e0o c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m.<\/td>\nT\u1eadp trung v\u00e0o vi\u1ec7c thu th\u1eadp m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, nh\u1ea5n m\u1ea1nh v\u00e0o d\u1eef li\u1ec7u v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7.<\/td>\n<\/tr>\n
          Ph\u1ee5 thu\u1ed9c v\u00e0o m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh<\/strong><\/td>\nLi\u00ean quan ch\u1eb7t ch\u1ebd \u0111\u1ebfn c\u00e1c m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng.<\/td>\nKh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh; \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho c\u01a1 s\u1edf d\u1eef li\u1ec7u trong nhi\u1ec1u ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh kh\u00e1c nhau.<\/td>\n<\/tr>\n
          S\u1eed d\u1ee5ng trong ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m<\/strong><\/td>\nTh\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng, m\u00f4 h\u00ecnh h\u00f3a d\u1ef1a tr\u00ean UML.<\/td>\nC\u1ea7n thi\u1ebft cho thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u, ph\u00e1t tri\u1ec3n l\u01b0\u1ee3c \u0111\u1ed3 v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n
          Thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c<\/strong><\/td>\nH\u1ed7 tr\u1ee3 c\u00e1c cu\u1ed9c th\u1ea3o lu\u1eadn thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c gi\u1eefa c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n v\u00e0 c\u00e1c b\u00ean li\u00ean quan.<\/td>\nGi\u00fap c\u00e1c qu\u1ea3n tr\u1ecb vi\u00ean c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n t\u1ea1o v\u00e0 t\u00e0i li\u1ec7u h\u00f3a c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n
          Kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng<\/strong><\/td>\nC\u00f3 th\u1ec3 m\u1edf r\u1ed9ng \u0111\u1ec3 t\u00edch h\u1ee3p c\u00e1c m\u1eabu thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m, giao di\u1ec7n v\u00e0 c\u00e1c kh\u00e1i ni\u1ec7m ki\u1ebfn tr\u00fac.<\/td>\n\u00cdt kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng h\u01a1n \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u00e1c m\u1eabu thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m kh\u00f4ng li\u00ean quan \u0111\u1ebfn c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/p>\n

          \u00a0<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          B\u1ea3ng n\u00e0y cung c\u1ea5p m\u1ed9t so s\u00e1nh r\u00f5 r\u00e0ng gi\u1eefa hai lo\u1ea1i s\u01a1 \u0111\u1ed3 trong nhi\u1ec1u kh\u00eda c\u1ea1nh, l\u00e0m n\u1ed5i b\u1eadt c\u00e1c \u1ee9ng d\u1ee5ng ch\u00ednh, c\u00e1c th\u00e0nh ph\u1ea7n, k\u00fd hi\u1ec7u v\u00e0 vai tr\u00f2 c\u1ee7a ch\u00fang trong c\u00e1c giai \u0111o\u1ea1n kh\u00e1c nhau c\u1ee7a ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u. Vi\u1ec7c l\u1ef1a ch\u1ecdn gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD ph\u1ee5 thu\u1ed9c v\u00e0o nhu c\u1ea7u c\u1ee5 th\u1ec3 c\u1ee7a d\u1ef1 \u00e1n v\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a c\u00e1c ho\u1ea1t \u0111\u1ed9ng thi\u1ebft k\u1ebf v\u00e0 m\u00f4 h\u00ecnh h\u00f3a.<\/p>\n

          T\u00f3m t\u1eaft<\/h2>\n

          B\u00e0i vi\u1ebft kh\u00e1m ph\u00e1 nh\u1eefng kh\u00e1c bi\u1ec7t ch\u00ednh gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD), hai c\u00f4ng c\u1ee5 thi\u1ebft y\u1ebfu trong thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u. S\u01a1 \u0111\u1ed3 l\u1edbp, ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng, t\u1eadp trung v\u00e0o vi\u1ec7c tr\u1ef1c quan h\u00f3a c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp v\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng trong m\u1ed9t h\u1ec7 th\u1ed1ng. M\u1eb7t kh\u00e1c, ERD l\u00e0 thi\u1ebft y\u1ebfu cho thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u, bi\u1ec3u di\u1ec5n c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 trong m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7.<\/p>\n

          S\u01a1 \u0111\u1ed3 l\u1edbp nh\u1ea5n m\u1ea1nh v\u00e0o c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, bao g\u1ed3m c\u00e1c l\u1edbp, thu\u1ed9c t\u00ednh, ph\u01b0\u01a1ng th\u1ee9c v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7, l\u00e0m cho ch\u00fang l\u00fd t\u01b0\u1edfng cho thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac. Ch\u00fang c\u00f3 kh\u1ea3 n\u0103ng m\u1edf r\u1ed9ng cao v\u00e0 th\u00fac \u0111\u1ea9y c\u00e1c cu\u1ed9c th\u1ea3o lu\u1eadn thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c.<\/p>\n

          Ng\u01b0\u1ee3c l\u1ea1i, ERD t\u1eadp trung v\u00e0o m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u, ghi l\u1ea1i c\u1ea5u tr\u00fac c\u1ee7a m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c b\u1ea3ng, c\u1ed9t, m\u1ed1i quan h\u1ec7 v\u00e0 r\u00e0ng bu\u1ed9c. ERD l\u00e0 kh\u00f4ng th\u1ec3 thi\u1ebfu \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 t\u1ed5 ch\u1ee9c c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u. Ch\u00fang kh\u00f4ng b\u1ecb r\u00e0ng bu\u1ed9c b\u1edfi b\u1ea5t k\u1ef3 m\u00f4 h\u00ecnh l\u1eadp tr\u00ecnh c\u1ee5 th\u1ec3 n\u00e0o v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong nhi\u1ec1u ng\u00f4n ng\u1eef l\u1eadp tr\u00ecnh kh\u00e1c nhau.<\/p>\n

          Vi\u1ec7c l\u1ef1a ch\u1ecdn gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD ph\u1ee5 thu\u1ed9c v\u00e0o tr\u1ecdng t\u00e2m v\u00e0 y\u00eau c\u1ea7u c\u1ee7a d\u1ef1 \u00e1n. S\u01a1 \u0111\u1ed3 l\u1edbp ph\u00f9 h\u1ee3p v\u1edbi ph\u00e1t tri\u1ec3n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac, trong khi ERD l\u00e0 thi\u1ebft y\u1ebfu cho c\u00e1c nhi\u1ec7m v\u1ee5 thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u. C\u1ea3 hai lo\u1ea1i s\u01a1 \u0111\u1ed3 n\u00e0y \u0111\u1ec1u \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong c\u00e1c giai \u0111o\u1ea1n kh\u00e1c nhau c\u1ee7a ph\u00e1t tri\u1ec3n v\u00e0 thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m, n\u00e2ng cao s\u1ef1 hi\u1ec3u bi\u1ebft v\u00e0 giao ti\u1ebfp v\u1ec1 c\u00e1c h\u1ec7 th\u1ed1ng v\u00e0 m\u00f4 h\u00ecnh d\u1eef li\u1ec7u ph\u1ee9c t\u1ea1p.<\/p>\n","protected":false},"excerpt":{"rendered":"

          Gi\u1edbi thi\u1ec7u S\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) l\u00e0 hai c\u00f4ng c\u1ee5 thi\u1ebft y\u1ebfu trong thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u. M\u1eb7c d\u00f9 ch\u00fang c\u00f3 m\u1ed9t s\u1ed1 \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng, nh\u01b0ng ch\u00fang ph\u1ee5c v\u1ee5 c\u00e1c m\u1ee5c \u0111\u00edch kh\u00e1c nhau v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c b\u1ed1i c\u1ea3nh kh\u00e1c nhau. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang t\u00f4i s\u1ebd kh\u00e1m ph\u00e1 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai lo\u1ea1i s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u01b0a ra c\u00e1c v\u00ed d\u1ee5 v\u00e0 th\u1ea3o lu\u1eadn v\u1ec1 khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng t\u1eebng lo\u1ea1i. S\u01a1 \u0111\u1ed3 l\u1edbp M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 l\u1edbp ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 thi\u1ebft k\u1ebf \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp v\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng trong m\u1ed9t h\u1ec7 th\u1ed1ng. \u0110\u00e2y l\u00e0 m\u1ed9t ph\u1ea7n thi\u1ebft y\u1ebfu c\u1ee7a Ng\u00f4n ng\u1eef m\u00f4 h\u00ecnh h\u00f3a th\u1ed1ng nh\u1ea5t (UML) v\u00e0 gi\u00fap h\u00ecnh dung c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a h\u1ec7 th\u1ed1ng. C\u00e1c th\u00e0nh ph\u1ea7n: L\u1edbp:Bi\u1ec3u di\u1ec5n b\u1ea3n v\u1ebd m\u1eabu cho m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh (th\u00e0nh vi\u00ean d\u1eef li\u1ec7u) v\u00e0 ph\u01b0\u01a1ng th\u1ee9c (h\u00e0m). Li\u00ean k\u1ebft:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp, bao g\u1ed3m c\u00e1c li\u00ean k\u1ebft m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. K\u1ebf th\u1eeba:Minh h\u1ecda c\u1ea5u tr\u00fac k\u1ebf th\u1eeba, cho th\u1ea5y c\u00e1c l\u1edbp n\u00e0o k\u1ebf th\u1eeba t\u1eeb c\u00e1c l\u1edbp kh\u00e1c. T\u1ed5ng h\u1ee3p v\u00e0 k\u1ebft h\u1ee3p:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 to\u00e0n th\u1ec3-ph\u1ea7n, ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t chi\u1ebfc xe h\u01a1i v\u00e0 \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3. Thu\u1ed9c t\u00ednh v\u00e0 thao t\u00e1c:Hi\u1ec3n th\u1ecb c\u00e1c thu\u1ed9c t\u00ednh (thu\u1ed9c t\u00ednh) v\u00e0 h\u00e0nh vi (ph\u01b0\u01a1ng th\u1ee9c) c\u1ee7a m\u1ed9t l\u1edbp. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t v\u00ed d\u1ee5 \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 bi\u1ec3u di\u1ec5n m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0 vi\u1ec7n b\u1eb1ng s\u01a1 \u0111\u1ed3 l\u1edbp: Trong s\u01a1 \u0111\u1ed3 l\u1edbp n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c l\u1edbp nh\u01b0Th\u01b0 vi\u1ec7n, S\u00e1ch, v\u00e0T\u00e1c gi\u1ea3, th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 (b\u1ea3ng) trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. N\u00f3 t\u1eadp trung v\u00e0o vi\u1ec7c ghi l\u1ea1i m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7. C\u00e1c th\u00e0nh ph\u1ea7n: Th\u1ef1c th\u1ec3: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t b\u1ea3ng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, th\u01b0\u1eddng t\u01b0\u01a1ng \u1ee9ng v\u1edbi c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c kh\u00e1i ni\u1ec7m trong th\u1ebf gi\u1edbi th\u1ef1c. Thu\u1ed9c t\u00ednh: Th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh ho\u1eb7c tr\u01b0\u1eddng c\u1ee7a m\u1ed9t th\u1ef1c th\u1ec3. M\u1ed1i quan h\u1ec7: Minh h\u1ecda c\u00e1ch c\u00e1c th\u1ef1c th\u1ec3 li\u00ean quan \u0111\u1ebfn nhau, bao g\u1ed3m c\u00e1c m\u1ed1i quan h\u1ec7 m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. Kh\u00f3a ch\u00ednh: X\u00e1c \u0111\u1ecbnh m\u1ed9t thu\u1ed9c t\u00ednh duy nh\u1ea5t ho\u1eb7c t\u1ed5 h\u1ee3p c\u00e1c thu\u1ed9c t\u00ednh gi\u00fap x\u00e1c \u0111\u1ecbnh duy nh\u1ea5t m\u1ed7i th\u1ef1c th\u1ec3. Kh\u00f3a ngo\u1ea1i: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t li\u00ean k\u1ebft gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n tham chi\u1ebfu trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t s\u01a1 \u0111\u1ed3 th\u1ef1c th\u1ec3 – m\u1ed1i quan h\u1ec7 cho m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed \u0111\u01a1n gi\u1ea3n: Trong s\u01a1 \u0111\u1ed3 n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c th\u1ef1c th\u1ec3 nh\u01b0Kh\u00e1ch h\u00e0ng, \u0110\u01a1n h\u00e0ng, v\u00e0S\u1ea3n ph\u1ea9m, c\u00f9ng v\u1edbi c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. C\u00e1c kh\u00f3a ngo\u1ea1i (CustomerID, ProductID) thi\u1ebft l\u1eadp c\u00e1c k\u1ebft n\u1ed1i gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 n\u00e0y. Khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng lo\u1ea1i n\u00e0o? S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp khi: Thi\u1ebft k\u1ebf c\u00e1c h\u1ec7 th\u1ed1ng h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng: N\u1ebfu b\u1ea1n \u0111ang l\u00e0m vi\u1ec7c tr\u00ean m\u1ed9t d\u1ef1 \u00e1n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u1ea7n bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang, h\u00e3y s\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp. M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m: S\u01a1 \u0111\u1ed3 l\u1edbp h\u1eefu \u00edch \u0111\u1ec3 tr\u1ef1c quan h\u00f3a c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, bao g\u1ed3m c\u00e1c c\u1ea5p l\u1edbp, giao di\u1ec7n v\u00e0 c\u00e1c ph\u1ee5 thu\u1ed9c. Thi\u1ebft k\u1ebf h\u1ee3p t\u00e1cS\u01a1 \u0111\u1ed3 l\u1edbp th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c bu\u1ed5i thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c \u0111\u1ec3 h\u1ed7 tr\u1ee3 th\u1ea3o lu\u1eadn gi\u1eefa c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n, nh\u00e0 thi\u1ebft k\u1ebf v\u00e0 c\u00e1c b\u00ean li\u00ean quan. S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 khi: Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u:Khi thi\u1ebft k\u1ebf m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, h\u00e3y s\u1eed d\u1ee5ng ERD \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c b\u1ea3ng, c\u00e1c thu\u1ed9c t\u00ednh c\u1ee7a ch\u00fang v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u:ERD l\u00e0 thi\u1ebft y\u1ebfu cho vi\u1ec7c m\u00f4 h\u00ecnh h\u00f3a v\u00e0 hi\u1ec3u y\u00eau c\u1ea7u d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 t\u1ed5 ch\u1ee9c c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00e0i li\u1ec7u c\u01a1 s\u1edf d\u1eef li\u1ec7u:ERD \u0111\u00f3ng vai tr\u00f2 l\u00e0 t\u00e0i li\u1ec7u qu\u00fd gi\u00e1 cho c\u00e1c qu\u1ea3n tr\u1ecb vi\u00ean c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n, m\u00f4 t\u1ea3 c\u1ea5u tr\u00fac v\u00e0 c\u00e1c r\u00e0ng bu\u1ed9c c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00f3m t\u1eaft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng so s\u00e1nh s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) \u1edf c\u00e1c kh\u00eda c\u1ea1nh kh\u00e1c nhau: Kh\u00eda c\u1ea1nh S\u01a1 \u0111\u1ed3 l\u1edbp S\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) M\u1ee5c \u0111\u00edch Bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m. Bi\u1ec3u di\u1ec5n c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u. C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng ch\u00ednh \u2013 Thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng<br>- M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m \u2013 Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7<br>- M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u C\u00e1c th\u00e0nh ph\u1ea7n \u2013 L\u1edbp<br>- Thu\u1ed9c t\u00ednh<br>- Ph\u01b0\u01a1ng th\u1ee9c (Thao t\u00e1c)<br>- Li\u00ean k\u1ebft<br>- K\u1ebf th\u1eeba<br>- T\u1ed5ng h\u1ee3p\/Th\u00e0nh ph\u1ea7n \u2013 Th\u1ef1c th\u1ec3 (B\u1ea3ng)<br>- Thu\u1ed9c t\u00ednh (C\u1ed9t)<br>- M\u1ed1i quan h\u1ec7<br>- Kh\u00f3a ch\u00ednh<br>- Kh\u00f3a ngo\u1ea1i S\u1ed1 l\u01b0\u1ee3ng \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 th\u1ec3 hi\u1ec7n c\u00e1c li\u00ean k\u1ebft gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c l\u1edbp. C\u00f3 th\u1ec3 bi\u1ec3u di\u1ec5n t\u00ednh \u0111a d\u1ea1ngS\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":6547,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_title":"","_yoast_wpseo_metadesc":"","_eb_attr":"","neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[17,7],"tags":[],"class_list":["post-6546","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-data-modeling-database","category-uml"],"yoast_head":"\nS\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh - Visual Paradigm Guides Vietnamese<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"S\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh - Visual Paradigm Guides Vietnamese\" \/>\n<meta property=\"og:description\" content=\"Gi\u1edbi thi\u1ec7u S\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) l\u00e0 hai c\u00f4ng c\u1ee5 thi\u1ebft y\u1ebfu trong thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u. M\u1eb7c d\u00f9 ch\u00fang c\u00f3 m\u1ed9t s\u1ed1 \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng, nh\u01b0ng ch\u00fang ph\u1ee5c v\u1ee5 c\u00e1c m\u1ee5c \u0111\u00edch kh\u00e1c nhau v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c b\u1ed1i c\u1ea3nh kh\u00e1c nhau. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang t\u00f4i s\u1ebd kh\u00e1m ph\u00e1 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai lo\u1ea1i s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u01b0a ra c\u00e1c v\u00ed d\u1ee5 v\u00e0 th\u1ea3o lu\u1eadn v\u1ec1 khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng t\u1eebng lo\u1ea1i. S\u01a1 \u0111\u1ed3 l\u1edbp M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 l\u1edbp ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 thi\u1ebft k\u1ebf \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp v\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng trong m\u1ed9t h\u1ec7 th\u1ed1ng. \u0110\u00e2y l\u00e0 m\u1ed9t ph\u1ea7n thi\u1ebft y\u1ebfu c\u1ee7a Ng\u00f4n ng\u1eef m\u00f4 h\u00ecnh h\u00f3a th\u1ed1ng nh\u1ea5t (UML) v\u00e0 gi\u00fap h\u00ecnh dung c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a h\u1ec7 th\u1ed1ng. C\u00e1c th\u00e0nh ph\u1ea7n: L\u1edbp:Bi\u1ec3u di\u1ec5n b\u1ea3n v\u1ebd m\u1eabu cho m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh (th\u00e0nh vi\u00ean d\u1eef li\u1ec7u) v\u00e0 ph\u01b0\u01a1ng th\u1ee9c (h\u00e0m). Li\u00ean k\u1ebft:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp, bao g\u1ed3m c\u00e1c li\u00ean k\u1ebft m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. K\u1ebf th\u1eeba:Minh h\u1ecda c\u1ea5u tr\u00fac k\u1ebf th\u1eeba, cho th\u1ea5y c\u00e1c l\u1edbp n\u00e0o k\u1ebf th\u1eeba t\u1eeb c\u00e1c l\u1edbp kh\u00e1c. T\u1ed5ng h\u1ee3p v\u00e0 k\u1ebft h\u1ee3p:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 to\u00e0n th\u1ec3-ph\u1ea7n, ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t chi\u1ebfc xe h\u01a1i v\u00e0 \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3. Thu\u1ed9c t\u00ednh v\u00e0 thao t\u00e1c:Hi\u1ec3n th\u1ecb c\u00e1c thu\u1ed9c t\u00ednh (thu\u1ed9c t\u00ednh) v\u00e0 h\u00e0nh vi (ph\u01b0\u01a1ng th\u1ee9c) c\u1ee7a m\u1ed9t l\u1edbp. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t v\u00ed d\u1ee5 \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 bi\u1ec3u di\u1ec5n m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0 vi\u1ec7n b\u1eb1ng s\u01a1 \u0111\u1ed3 l\u1edbp: Trong s\u01a1 \u0111\u1ed3 l\u1edbp n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c l\u1edbp nh\u01b0Th\u01b0 vi\u1ec7n, S\u00e1ch, v\u00e0T\u00e1c gi\u1ea3, th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 (b\u1ea3ng) trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. N\u00f3 t\u1eadp trung v\u00e0o vi\u1ec7c ghi l\u1ea1i m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7. C\u00e1c th\u00e0nh ph\u1ea7n: Th\u1ef1c th\u1ec3: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t b\u1ea3ng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, th\u01b0\u1eddng t\u01b0\u01a1ng \u1ee9ng v\u1edbi c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c kh\u00e1i ni\u1ec7m trong th\u1ebf gi\u1edbi th\u1ef1c. Thu\u1ed9c t\u00ednh: Th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh ho\u1eb7c tr\u01b0\u1eddng c\u1ee7a m\u1ed9t th\u1ef1c th\u1ec3. M\u1ed1i quan h\u1ec7: Minh h\u1ecda c\u00e1ch c\u00e1c th\u1ef1c th\u1ec3 li\u00ean quan \u0111\u1ebfn nhau, bao g\u1ed3m c\u00e1c m\u1ed1i quan h\u1ec7 m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. Kh\u00f3a ch\u00ednh: X\u00e1c \u0111\u1ecbnh m\u1ed9t thu\u1ed9c t\u00ednh duy nh\u1ea5t ho\u1eb7c t\u1ed5 h\u1ee3p c\u00e1c thu\u1ed9c t\u00ednh gi\u00fap x\u00e1c \u0111\u1ecbnh duy nh\u1ea5t m\u1ed7i th\u1ef1c th\u1ec3. Kh\u00f3a ngo\u1ea1i: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t li\u00ean k\u1ebft gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n tham chi\u1ebfu trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t s\u01a1 \u0111\u1ed3 th\u1ef1c th\u1ec3 – m\u1ed1i quan h\u1ec7 cho m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed \u0111\u01a1n gi\u1ea3n: Trong s\u01a1 \u0111\u1ed3 n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c th\u1ef1c th\u1ec3 nh\u01b0Kh\u00e1ch h\u00e0ng, \u0110\u01a1n h\u00e0ng, v\u00e0S\u1ea3n ph\u1ea9m, c\u00f9ng v\u1edbi c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. C\u00e1c kh\u00f3a ngo\u1ea1i (CustomerID, ProductID) thi\u1ebft l\u1eadp c\u00e1c k\u1ebft n\u1ed1i gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 n\u00e0y. Khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng lo\u1ea1i n\u00e0o? S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp khi: Thi\u1ebft k\u1ebf c\u00e1c h\u1ec7 th\u1ed1ng h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng: N\u1ebfu b\u1ea1n \u0111ang l\u00e0m vi\u1ec7c tr\u00ean m\u1ed9t d\u1ef1 \u00e1n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u1ea7n bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang, h\u00e3y s\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp. M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m: S\u01a1 \u0111\u1ed3 l\u1edbp h\u1eefu \u00edch \u0111\u1ec3 tr\u1ef1c quan h\u00f3a c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, bao g\u1ed3m c\u00e1c c\u1ea5p l\u1edbp, giao di\u1ec7n v\u00e0 c\u00e1c ph\u1ee5 thu\u1ed9c. Thi\u1ebft k\u1ebf h\u1ee3p t\u00e1cS\u01a1 \u0111\u1ed3 l\u1edbp th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c bu\u1ed5i thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c \u0111\u1ec3 h\u1ed7 tr\u1ee3 th\u1ea3o lu\u1eadn gi\u1eefa c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n, nh\u00e0 thi\u1ebft k\u1ebf v\u00e0 c\u00e1c b\u00ean li\u00ean quan. S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 khi: Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u:Khi thi\u1ebft k\u1ebf m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, h\u00e3y s\u1eed d\u1ee5ng ERD \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c b\u1ea3ng, c\u00e1c thu\u1ed9c t\u00ednh c\u1ee7a ch\u00fang v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u:ERD l\u00e0 thi\u1ebft y\u1ebfu cho vi\u1ec7c m\u00f4 h\u00ecnh h\u00f3a v\u00e0 hi\u1ec3u y\u00eau c\u1ea7u d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 t\u1ed5 ch\u1ee9c c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00e0i li\u1ec7u c\u01a1 s\u1edf d\u1eef li\u1ec7u:ERD \u0111\u00f3ng vai tr\u00f2 l\u00e0 t\u00e0i li\u1ec7u qu\u00fd gi\u00e1 cho c\u00e1c qu\u1ea3n tr\u1ecb vi\u00ean c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n, m\u00f4 t\u1ea3 c\u1ea5u tr\u00fac v\u00e0 c\u00e1c r\u00e0ng bu\u1ed9c c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00f3m t\u1eaft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng so s\u00e1nh s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) \u1edf c\u00e1c kh\u00eda c\u1ea1nh kh\u00e1c nhau: Kh\u00eda c\u1ea1nh S\u01a1 \u0111\u1ed3 l\u1edbp S\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) M\u1ee5c \u0111\u00edch Bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m. Bi\u1ec3u di\u1ec5n c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u. C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng ch\u00ednh \u2013 Thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng<br>- M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m \u2013 Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7<br>- M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u C\u00e1c th\u00e0nh ph\u1ea7n \u2013 L\u1edbp<br>- Thu\u1ed9c t\u00ednh<br>- Ph\u01b0\u01a1ng th\u1ee9c (Thao t\u00e1c)<br>- Li\u00ean k\u1ebft<br>- K\u1ebf th\u1eeba<br>- T\u1ed5ng h\u1ee3p\/Th\u00e0nh ph\u1ea7n \u2013 Th\u1ef1c th\u1ec3 (B\u1ea3ng)<br>- Thu\u1ed9c t\u00ednh (C\u1ed9t)<br>- M\u1ed1i quan h\u1ec7<br>- Kh\u00f3a ch\u00ednh<br>- Kh\u00f3a ngo\u1ea1i S\u1ed1 l\u01b0\u1ee3ng \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 th\u1ec3 hi\u1ec7n c\u00e1c li\u00ean k\u1ebft gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c l\u1edbp. 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M\u1eb7c d\u00f9 ch\u00fang c\u00f3 m\u1ed9t s\u1ed1 \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng, nh\u01b0ng ch\u00fang ph\u1ee5c v\u1ee5 c\u00e1c m\u1ee5c \u0111\u00edch kh\u00e1c nhau v\u00e0 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c b\u1ed1i c\u1ea3nh kh\u00e1c nhau. Trong b\u00e0i vi\u1ebft n\u00e0y, ch\u00fang t\u00f4i s\u1ebd kh\u00e1m ph\u00e1 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai lo\u1ea1i s\u01a1 \u0111\u1ed3 n\u00e0y, \u0111\u01b0a ra c\u00e1c v\u00ed d\u1ee5 v\u00e0 th\u1ea3o lu\u1eadn v\u1ec1 khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng t\u1eebng lo\u1ea1i. S\u01a1 \u0111\u1ed3 l\u1edbp M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 l\u1edbp ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong l\u1eadp tr\u00ecnh h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 thi\u1ebft k\u1ebf \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp v\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng trong m\u1ed9t h\u1ec7 th\u1ed1ng. \u0110\u00e2y l\u00e0 m\u1ed9t ph\u1ea7n thi\u1ebft y\u1ebfu c\u1ee7a Ng\u00f4n ng\u1eef m\u00f4 h\u00ecnh h\u00f3a th\u1ed1ng nh\u1ea5t (UML) v\u00e0 gi\u00fap h\u00ecnh dung c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a h\u1ec7 th\u1ed1ng. C\u00e1c th\u00e0nh ph\u1ea7n: L\u1edbp:Bi\u1ec3u di\u1ec5n b\u1ea3n v\u1ebd m\u1eabu cho m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, x\u00e1c \u0111\u1ecbnh c\u00e1c thu\u1ed9c t\u00ednh (th\u00e0nh vi\u00ean d\u1eef li\u1ec7u) v\u00e0 ph\u01b0\u01a1ng th\u1ee9c (h\u00e0m). Li\u00ean k\u1ebft:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c l\u1edbp, bao g\u1ed3m c\u00e1c li\u00ean k\u1ebft m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. K\u1ebf th\u1eeba:Minh h\u1ecda c\u1ea5u tr\u00fac k\u1ebf th\u1eeba, cho th\u1ea5y c\u00e1c l\u1edbp n\u00e0o k\u1ebf th\u1eeba t\u1eeb c\u00e1c l\u1edbp kh\u00e1c. T\u1ed5ng h\u1ee3p v\u00e0 k\u1ebft h\u1ee3p:Bi\u1ec3u di\u1ec5n c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 to\u00e0n th\u1ec3-ph\u1ea7n, ch\u1eb3ng h\u1ea1n nh\u01b0 m\u1ed9t chi\u1ebfc xe h\u01a1i v\u00e0 \u0111\u1ed9ng c\u01a1 c\u1ee7a n\u00f3. Thu\u1ed9c t\u00ednh v\u00e0 thao t\u00e1c:Hi\u1ec3n th\u1ecb c\u00e1c thu\u1ed9c t\u00ednh (thu\u1ed9c t\u00ednh) v\u00e0 h\u00e0nh vi (ph\u01b0\u01a1ng th\u1ee9c) c\u1ee7a m\u1ed9t l\u1edbp. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t v\u00ed d\u1ee5 \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 bi\u1ec3u di\u1ec5n m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0 vi\u1ec7n b\u1eb1ng s\u01a1 \u0111\u1ed3 l\u1edbp: Trong s\u01a1 \u0111\u1ed3 l\u1edbp n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c l\u1edbp nh\u01b0Th\u01b0 vi\u1ec7n, S\u00e1ch, v\u00e0T\u00e1c gi\u1ea3, th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) M\u1ee5c \u0111\u00edch: S\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD) ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 bi\u1ec3u di\u1ec5n c\u1ea5u tr\u00fac v\u00e0 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 (b\u1ea3ng) trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. N\u00f3 t\u1eadp trung v\u00e0o vi\u1ec7c ghi l\u1ea1i m\u00f4 h\u00ecnh d\u1eef li\u1ec7u, bao g\u1ed3m c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7. C\u00e1c th\u00e0nh ph\u1ea7n: Th\u1ef1c th\u1ec3: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t b\u1ea3ng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, th\u01b0\u1eddng t\u01b0\u01a1ng \u1ee9ng v\u1edbi c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c kh\u00e1i ni\u1ec7m trong th\u1ebf gi\u1edbi th\u1ef1c. Thu\u1ed9c t\u00ednh: Th\u1ec3 hi\u1ec7n c\u00e1c thu\u1ed9c t\u00ednh ho\u1eb7c tr\u01b0\u1eddng c\u1ee7a m\u1ed9t th\u1ef1c th\u1ec3. M\u1ed1i quan h\u1ec7: Minh h\u1ecda c\u00e1ch c\u00e1c th\u1ef1c th\u1ec3 li\u00ean quan \u0111\u1ebfn nhau, bao g\u1ed3m c\u00e1c m\u1ed1i quan h\u1ec7 m\u1ed9t-\u0111\u1ed1i-m\u1ed9t, m\u1ed9t-\u0111\u1ed1i-nhi\u1ec1u v\u00e0 nhi\u1ec1u-\u0111\u1ed1i-nhi\u1ec1u. Kh\u00f3a ch\u00ednh: X\u00e1c \u0111\u1ecbnh m\u1ed9t thu\u1ed9c t\u00ednh duy nh\u1ea5t ho\u1eb7c t\u1ed5 h\u1ee3p c\u00e1c thu\u1ed9c t\u00ednh gi\u00fap x\u00e1c \u0111\u1ecbnh duy nh\u1ea5t m\u1ed7i th\u1ef1c th\u1ec3. Kh\u00f3a ngo\u1ea1i: \u0110\u1ea1i di\u1ec7n cho m\u1ed9t li\u00ean k\u1ebft gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 v\u00e0 \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n tham chi\u1ebfu trong c\u01a1 s\u1edf d\u1eef li\u1ec7u. V\u00ed d\u1ee5: H\u00e3y c\u00f9ng xem x\u00e9t m\u1ed9t s\u01a1 \u0111\u1ed3 th\u1ef1c th\u1ec3 – m\u1ed1i quan h\u1ec7 cho m\u1ed9t h\u1ec7 th\u1ed1ng th\u01b0\u01a1ng m\u1ea1i \u0111i\u1ec7n t\u1eed \u0111\u01a1n gi\u1ea3n: Trong s\u01a1 \u0111\u1ed3 n\u00e0y, ch\u00fang ta c\u00f3 c\u00e1c th\u1ef1c th\u1ec3 nh\u01b0Kh\u00e1ch h\u00e0ng, \u0110\u01a1n h\u00e0ng, v\u00e0S\u1ea3n ph\u1ea9m, c\u00f9ng v\u1edbi c\u00e1c thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang. C\u00e1c kh\u00f3a ngo\u1ea1i (CustomerID, ProductID) thi\u1ebft l\u1eadp c\u00e1c k\u1ebft n\u1ed1i gi\u1eefa c\u00e1c th\u1ef1c th\u1ec3 n\u00e0y. Khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng lo\u1ea1i n\u00e0o? S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp khi: Thi\u1ebft k\u1ebf c\u00e1c h\u1ec7 th\u1ed1ng h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng: N\u1ebfu b\u1ea1n \u0111ang l\u00e0m vi\u1ec7c tr\u00ean m\u1ed9t d\u1ef1 \u00e1n ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u1ea7n bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang, h\u00e3y s\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 l\u1edbp. M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m: S\u01a1 \u0111\u1ed3 l\u1edbp h\u1eefu \u00edch \u0111\u1ec3 tr\u1ef1c quan h\u00f3a c\u1ea5u tr\u00fac t\u0129nh c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m, bao g\u1ed3m c\u00e1c c\u1ea5p l\u1edbp, giao di\u1ec7n v\u00e0 c\u00e1c ph\u1ee5 thu\u1ed9c. Thi\u1ebft k\u1ebf h\u1ee3p t\u00e1cS\u01a1 \u0111\u1ed3 l\u1edbp th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c bu\u1ed5i thi\u1ebft k\u1ebf h\u1ee3p t\u00e1c \u0111\u1ec3 h\u1ed7 tr\u1ee3 th\u1ea3o lu\u1eadn gi\u1eefa c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n, nh\u00e0 thi\u1ebft k\u1ebf v\u00e0 c\u00e1c b\u00ean li\u00ean quan. S\u1eed d\u1ee5ng s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 khi: Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u:Khi thi\u1ebft k\u1ebf m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7, h\u00e3y s\u1eed d\u1ee5ng ERD \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1c b\u1ea3ng, c\u00e1c thu\u1ed9c t\u00ednh c\u1ee7a ch\u00fang v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang. M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u:ERD l\u00e0 thi\u1ebft y\u1ebfu cho vi\u1ec7c m\u00f4 h\u00ecnh h\u00f3a v\u00e0 hi\u1ec3u y\u00eau c\u1ea7u d\u1eef li\u1ec7u, \u0111\u1ea3m b\u1ea3o t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u v\u00e0 t\u1ed5 ch\u1ee9c c\u00e1c l\u01b0\u1ee3c \u0111\u1ed3 c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00e0i li\u1ec7u c\u01a1 s\u1edf d\u1eef li\u1ec7u:ERD \u0111\u00f3ng vai tr\u00f2 l\u00e0 t\u00e0i li\u1ec7u qu\u00fd gi\u00e1 cho c\u00e1c qu\u1ea3n tr\u1ecb vi\u00ean c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 nh\u00e0 ph\u00e1t tri\u1ec3n, m\u00f4 t\u1ea3 c\u1ea5u tr\u00fac v\u00e0 c\u00e1c r\u00e0ng bu\u1ed9c c\u1ee7a c\u01a1 s\u1edf d\u1eef li\u1ec7u. T\u00f3m t\u1eaft s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 ERD D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t b\u1ea3ng so s\u00e1nh s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa s\u01a1 \u0111\u1ed3 l\u1edbp v\u00e0 s\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) \u1edf c\u00e1c kh\u00eda c\u1ea1nh kh\u00e1c nhau: Kh\u00eda c\u1ea1nh S\u01a1 \u0111\u1ed3 l\u1edbp S\u01a1 \u0111\u1ed3 Entiti-Quan h\u1ec7 (ERD) M\u1ee5c \u0111\u00edch Bi\u1ec3u di\u1ec5n c\u00e1c l\u1edbp, \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c m\u1ed1i quan h\u1ec7 c\u1ee7a ch\u00fang trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng v\u00e0 ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m. Bi\u1ec3u di\u1ec5n c\u00e1c th\u1ef1c th\u1ec3, thu\u1ed9c t\u00ednh v\u00e0 m\u1ed1i quan h\u1ec7 trong thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 m\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u. C\u00e1c tr\u01b0\u1eddng h\u1ee3p s\u1eed d\u1ee5ng ch\u00ednh \u2013 Thi\u1ebft k\u1ebf ph\u1ea7n m\u1ec1m h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng<br>- M\u00f4 h\u00ecnh h\u00f3a ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m \u2013 Thi\u1ebft k\u1ebf c\u01a1 s\u1edf d\u1eef li\u1ec7u quan h\u1ec7<br>- M\u00f4 h\u00ecnh h\u00f3a d\u1eef li\u1ec7u C\u00e1c th\u00e0nh ph\u1ea7n \u2013 L\u1edbp<br>- Thu\u1ed9c t\u00ednh<br>- Ph\u01b0\u01a1ng th\u1ee9c (Thao t\u00e1c)<br>- Li\u00ean k\u1ebft<br>- K\u1ebf th\u1eeba<br>- T\u1ed5ng h\u1ee3p\/Th\u00e0nh ph\u1ea7n \u2013 Th\u1ef1c th\u1ec3 (B\u1ea3ng)<br>- Thu\u1ed9c t\u00ednh (C\u1ed9t)<br>- M\u1ed1i quan h\u1ec7<br>- Kh\u00f3a ch\u00ednh<br>- Kh\u00f3a ngo\u1ea1i S\u1ed1 l\u01b0\u1ee3ng \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 th\u1ec3 hi\u1ec7n c\u00e1c li\u00ean k\u1ebft gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ho\u1eb7c l\u1edbp. C\u00f3 th\u1ec3 bi\u1ec3u di\u1ec5n t\u00ednh \u0111a d\u1ea1ngS\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh","og_url":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/","og_site_name":"Visual Paradigm Guides Vietnamese","article_published_time":"2026-02-05T01:40:38+00:00","og_image":[{"width":349,"height":604,"url":"https:\/\/guides.visual-paradigm.com\/vn\/wp-content\/uploads\/sites\/10\/2026\/02\/img_6503ed36dba8b.png","type":"image\/png"}],"twitter_card":"summary_large_image","twitter_misc":{"\u0110\u01b0\u1ee3c vi\u1ebft b\u1edfi":"vpadmin","\u01af\u1edbc t\u00ednh th\u1eddi gian \u0111\u1ecdc":"5 ph\u00fat"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/#article","isPartOf":{"@id":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/"},"headline":"S\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh","datePublished":"2026-02-05T01:40:38+00:00","mainEntityOfPage":{"@id":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/"},"wordCount":2786,"commentCount":0,"image":{"@id":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/#primaryimage"},"thumbnailUrl":"https:\/\/guides.visual-paradigm.com\/vn\/wp-content\/uploads\/sites\/10\/2026\/02\/img_6503ed36dba8b.png","articleSection":["Data Modeling \/ Database","UML"],"inLanguage":"vi","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/","url":"https:\/\/guides.visual-paradigm.com\/vn\/class-diagram-vs-entity-relationship-diagram-erd-a-comparative-guide\/","name":"S\u01a1 \u0111\u1ed3 l\u1edbp so v\u1edbi s\u01a1 \u0111\u1ed3 quan h\u1ec7 th\u1ef1c th\u1ec3 (ERD): H\u01b0\u1edbng d\u1eabn so s\u00e1nh - 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