Research of Acyclic XML Document by mxp28572

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									      35                  19                                                                                                                                   2009   10
    Vol.35               No.19                                          Computer Engineering                                                                   October 2009

    ·                                   ·                               1000   3428(2009)19 0097         02                                  A                            TP391



                                                                        XML
                                                              (                                               071003)

                                                                                                                                                                  γ
                             XML               XML_ γ                                         XML_ γ             XML


                                       XML_ γ


                                               Research of Acyclic XML Document
                                                            WANG Gui-lan, WANG Zhen-qi, LUO Xian-jin
                              (Information and Network Management Center, North China Electric Power University, Baoding 071003)

     Abstract        Acyclic database has many good characteristics, so acyclic is an important characteristic for database schema. Based on γ acyclic
 database schema, this paper presents the definitions of none XML_ γ cycle, the characteristics of none XML_ γ cycle in XML documents and
 design method of XML schema for none XML_ γ cycle. Theory analysis proves the effectiveness of the rules designed.

     Key words           normalization; ambiguity; XML_ γ cycle


                                                                                                                                                                        XML
                                                                                                                               FDXML[3]
                                                                                                          4 XML                    FDXML
     [1]             3                                  α          β           γ                  ( Q, ⎡ P , P
                                                                                                       ⎣  x1    x2   ,   , Pxn → Py ⎤
                                                                                                                                    ⎦        )
           γ    ⇒        β         β    ⇒      α                    γ                                (1) Q           FDXML                                              (
                                                                                                                      )             FDXML                                 (2)
            XML                                                                               Pxi                    LHS(Left-Hand-Side)                                  LHS
           XML
                                                                                                                         XML
                                               XML                 XML
                                                                                                    LHS                                           LHS
                              XML
                                                                                                                         (3) Py              RHS(Right-Hand-Side)
                                                                                                    RHS                                          XML
                                                                                                                             RHS                                  RHS
1
                                                                                                                 2             FDXML                   Q
                1 DTD                  G=(N,L)                N
                                         [2]                                              LHS                                                          RHS
        L
                                                                                                                         2
                 2 DTD                  N=(E|A| ∗ )                E     DTD
                (element) A            DTD                        (attribute) ∗
                                                                                                                                                                      2
                       0                 0                                  DTD

                3 DTD                           N1     N2                          N 1,
N2 ∈ N         N2   N1                                       DTD
                                                                                                          5                      H                             H=<V, E>
N2                       ∗              N1      N2                  N1     ∗       ∗
                                                                                          V                              V                         H           E                (
N2         2
                                                                                                     )                   E                                 V
               DTD
                                                                                              V                                          E
                     2                             2
                                                                                                                                                               (200611021)
                                                                                                                         (1979       )                                      XML
                                                                                                    OLAP
                                                                               XML                        2009-01-10                 E-mail       yu_bing_2000@163.com

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     R={R1,R2,          ,Rp}                             HR          HR=<V, E>                                                                  XML                               XML_ γ
V                           E             H                      R                                   Ai                      XML                   RXML={ R1 , R2 , , Rk }
             HR                             vi R                                        Rj                                                      XML_ γ                         true                                    false
HR                           ej           vi∈ej                  Ai                          Rj                    (1)           RXML                       XML              HXML=(N,E)
         H                                                                                     H                   (2)       HXML
                           RED(H)                                                                                  1)         1                                 1
         6 DTD                  G=(Ve, Va, Vo, Ee, Eo, fe, fo)                                                     2)         1                        1
   V=V=Ve Va Vo           (1)Ve DTD                                                                                3)         2                                                                     1
(2)Va   DTD                      (3)Vo   DTD                                                                       4)         2
          Vo ={*, ?, +} (4)Ee
             (5)Eo                                        (6)fe                                                    5)
   Ee V×V                 (    ) (7)fo Eo V×V                                                                      (3)           HXML                                 true                               false
      (     )                                                                                                                                                                                             XML_ γ
          7 XML             (RXML)               DTD                                                                                               XML_ γ
FDXML                FDXML                                                                                S1 , v1 , S 2 , v2 ,   , S n , vn , S n+1             XML_ γ                              vi                 2
FDXML                  XML
                                                                                                                                 1)                                                                           vi
     DTD     XML Schema              XML
                                                                                                                    XML_ γ                             XML_ γ                                  vi                   HXML
         XML                           XML
                                                                                                                                                                                  2
                                                                                                                                                                                          2)
                                                              XML
                                                                                                                   XML_ γ                          XML_ γ                             S1 , S 2 ,    , Sn            HXML
              8          XML                  DTD                                   U           U
     XML                   RXML                       RXML                                      HXML                                                                          2
                   RXML                                                                                       3)                                   2                                                XML_ γ
         HXML        XML                     RXML                                                                        A                 B                                      S'
             9                             XML                HXML                                                                    A        B                    S'
                   S1 , v1 , S2 , v2 ,     , Sn , vn , Sn+1                (1) v1 , v2 , , vn               A, B                                                                                              HXML
                                                                                                          XML_ γ                                                                      HXML                    XML_ γ
HXML                                  (2) S1 , S2 , , Sn        HXML
     S1 = S n+1        (3) n      3                                    3
                                                                                                          XML_ γ
(4) vi ∈ Si ∩ Si +1 ,1 i              n       (5)                     1      ( i, j )        n, i ≠ j ,
                                                                                                          4              XML_ γ
 j ≠ i + 1, j ≠ i − 1 vi ∉ S j                                                  XML_ γ
                                                                                                                                      XML_ γ
                  10                      XML          HXML                                                                                                                                          XML
XML_ γ                                              XML_ γ
XML_ γ                                        XML                              HXML
     XML_ γ                                                   XML_ γ                                                                                                                  (        3NF, BCNF)
             XML_ γ
2     XML                                                                                                                                   XML
       HXML                                         XML
        HXML
HXML
                         XML (HXML)
                  XML     DTD                                                                             XML_ γ
                  XML   HXML={N,E}                                                                                       XML_ γ                XML                        RXML
    (1)             DTD                                                                                                                   H1 , H 2 ,       , H n , H1 = ( N1 , E1 )       E1
    (2)             DTD                                                                  DTD              RXML = H1               H i = ( Ni , Ei ) , H i+1 = ( Ni +1 , Ei+1 ) , 1 i n                    ( H i , H i+1 )
  FDXML                        FDXML                                                                                                                   e' ∈ Ei+1 , Ni+1 = Ni ∪ e' , Ei+1 = Ei ∪ e' , e' ∩ Ni
    (3)                FDXML                                               XML
RXML={ R1 , R2 , , Rk }
       (4)        RXML             XML                HXML={N,E}
                                                                                                                   (1)           H i = ( N i , Ei )                   e ∈ Ei , N ' = {u | u ∈ Ei − e}
             XML_ γ
3                                          XML
                                                 DTD
                                                                                                              e' ∩ N i ⊆ e            e ∩ N i' ⊆ e' ∩ N i                             (
                                                                                                                                                                           H i +1 = N i ∪ e' , Ei ∪ e'             )
XML_ γ                                        HXML                                                                 (2)           H i = ( N i , Ei )                  Ei                    e             e ∩ Ni ⊆ e
                                                                                                                                                                                                          '


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