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dbase flie format




  ----------------------------------------------------------------------------
  genaral format of .dbf files in xbase languages 18-nov-96
  ----------------------------------------------------------------------------
  applies for / supported by:
  fs = flagship d3 = dbaseiii+
  fb = foxbase d4 = dbaseiv
  fp = foxpro d5 = dbasev
  cl = clipper
  1、dbf structure
  ================
  byte description
  ------+--------------------------------------
  0..n .dbf header (see 2 for size, byte 8)
  n+1 1st record of fixed length (see 2&3) \
  2nd record (see 2 for size, byte 10) \ if dbf is
  ... / not empty
  last record /
  last optional: 0x1a (eof byte)
  2、dbf header (variable size, depending on field count)
  =======================================================
  byte size contents description applies for (supported by)
  ----+----+--------+----------------------------+-----------------------------
  00 1 0x03 plain .dbf fs, d3, d4, d5, fb, fp, cl
  0x04 plain .dbf d4, d5 (fs)
  0x05 plain .dbf d5, fp (fs)
  0x43 with .dbv memo var size fs
  0xb3 with .dbv and .dbt memo fs
  0x83 with .dbt memo fs, d3, d4, d5, fb, fp, cl
  0x8b with .dbt memo in d4 format d4, d5
  0x8e with sql table d4, d5
  0xf5 with .fmp memo fp
  01 3 yymmdd last update digits all
  04 4 ulong number of records in file all
  08 2 ushort header size in bytes all
  10 2 ushort record size in bytes all
  12 2 0,0 reserved all
  14 1 0x01 begin transaction d4, d5
  0x00 end transaction d4, d5
  0x00 ignored fs, d3, fb, fp, cl
  15 1 0x01 encryptpted d4, d5
  0x00 normal visible all
  16 12 0 (1) multi-user environment use d4,d5
  28 1 0x01 production index exists fp, d4, d5
  0x00 index upon demand all
  29 1 n language driver id d4, d5
  0x01 codepage 437 dos usa fp
  0x02 codepage 850 dos multi ling fp
  0x03 codepage 1251 windows ansi fp
  0xc8 codepage 1250 windows ee fp
  0x00 ignored fs, d3, fb, fp, cl
  30 2 0,0 reserved all
  32 n*32 field descriptor, see (2a) all
  +1 1 0x0d header record terminator all
  2a. field descriptor array in dbf header (fix 32 bytes for each field)
  ========================================
   byte size contents description applies for (supported by)
  ----+----+--------+----------------------------+-----------------------------
  0 11 asci field name, 0x00 termin. all
  11 1 asci field type (see 2b) all
  12 4 n,n,n,n fld address in memory d3
  n,n,0,0 offset from record begin fp
  0,0,0,0 ignored fs, d4, d5, fb, cl
  16 1 byte field length, bin (see 2b) all \ fs,cl: for c field type,
  17 1 byte decimal count, bin all / both used for fld lng
  18 2 0,0 reserved all
  20 1 byte work area id d4, d5
  0x00 unused fs, d3, fb, fp, cl
  21 2 n,n multi-user dbase d3, d4, d5
  0,0 ignored fs, fb, fp, cl
  23 1 0x01 set fields d3, d4, d5
  0x00 ignored fs, fb, fp, cl
  24 7 0..0 reserved all
  31 1 0x01 field is in .mdx index d4, d5
  0x00 ignored fs, d3, fb, fp, cl
  2b. field type and size in dbf header, field descriptor (1 byte)
  =======================================================
  size type description/storage applies for (supported by)
  ------+---------+------------------------------+-----------------------------
  c 1..n char ascii (oem code page chars) all
  rest= space, not \0 term.
  n = 1..64kb (using deci count) fs
  n = 1..32kb (using deci count) fp, cl
  n = 1..254 all
  d 8 date 8 ascii digits (0..9) in the all
  yyyymmdd format
  f 1..n numeric ascii digits (-.0123456789) fs, d4, d5, fp
  variable pos. of float.point
  n = 1..20
  n 1..n numeric ascii digits (-.0123456789) all
  fix posit/no float.point
  n = 1..20 fs, fp, cl
  n = 1..18 d3, d4, d5, fb
  l 1 logical ascii chars (yynnttff space) fs, d3, fb, fp, cl
  ascii chars (yynnttff ?) d4, d5 (fs)
  m 10 memo 10 digits repres. the start all
  block posit. in .dbt file, or
  10spaces if no entry in memo
  v 10 variable variable, bin/asc data in .dbv fs
  4bytes bin= start pos in memo
  4bytes bin= block size
  1byte = subtype
  1byte = reserved (0x1a)
  10spaces if no entry in .dbv
  p 10 picture binary data in .ftp fp
  structure like m
  b 10 binary binary data in .dbt d5
  structure like m
  g 10 general ole objects d5, fp
  structure like m
  2 2 short int binary int max +/- 32767 fs
  4 4 long int binary int max +/- 2147483647 fs
  8 8 double binary signed double ieee fs
  3. each dbf record (fix length)
  ==================
   byte size description applies for (supported by)
  ------+----+--------------------------------------+--------------------------
  0 1 deleted flag "*" or not deleted " " all
  1..n 1.. x-times contents of fields, fixed all
  length, unterminated.
  for n, see (2) byte 10..11
   ---
  multisoft datentechnik gmbh






[来源:原创] [作者:admin] [日期:10-01-18] [热度:]