Question

如何在十六进制查看器中检查dbf文件类型的字节以检索dbf版本？

下面的示例屏幕截图取自FoxBASE + / Dbase III plus，没有备忘录

基于http://www.digitalpreservation.gov/formats/fdd/fdd000325.shtml的文章。

0x03 = FoxBASE + / Dbase III plus，没有备忘录

我能理解第一行第一个字符03 = 0x03吗？

03 75 02 11 92 00 00

以下是我想检查的未知数据库版本。它以04 75 02 10 DF开头我怎么知道这个版本的dBase是什么？

我尝试使用php dbase_open连接，但它不起作用。（错误消息：'警告：dbase_open（）：无法打开数据库C：...'）

Answer 1

我想我找到了anwser，http://www.dbase.com/KnowledgeBase/int/db7_file_fmt.htm

对于dBASE等级7，

04 = 4。

标题结构与dbase网站中描述的完全相同。

Byte    Contents      Description
0       1 byte        Valid dBASE for Windows table file, bits 0-2 indicate version number: 3 for dBASE Level 5, 4 for dBASE Level 7. Bit 3 and bit 7 indicate presence of a dBASE IV or dBASE for Windows memo file; bits 4-6 indicate the presence of a dBASE IV SQL table; bit 7 indicates the presence of any .DBT memo file (either a dBASE III PLUS type or a dBASE IV or dBASE for Windows memo file).
1-3     3 bytes       Date of last update; in YYMMDD format.  Each byte contains the number as a binary.  YY is added to a base of 1900 decimal to determine the actual year. Therefore, YY has possible values from 0x00-0xFF, which allows for a range from 1900-2155.
4-7     32-bit        Number of records in the table. (Least significant byte first.)
8-9     16-bit        Number of bytes in the header. (Least significant byte first.)
10-11   16-bit        Number of bytes in the record. (Least significant byte first.)
12-13   2 bytes       Reserved; filled with zeros.
14      1 byte        Flag indicating incomplete dBASE IV transaction.
15      1 byte        dBASE IV encryption flag.
16-27   12 bytes      Reserved for multi-user processing.
28      1 byte        Production MDX flag; 0x01 if a production .MDX file exists for this table; 0x00 if no .MDX file exists.
29      1 byte        Language driver ID.
30-31   2 bytes       Reserved; filled with zeros.
32-63   32 bytes      Language driver name.
64-67   4 bytes       Reserved.
68-n    48 bytes each   Field Descriptor Array (see 1.2).
n+1     1 byte        0x0D stored as the Field Descriptor terminator.
n+2                   Field Properties Structure

1.2字段描述符数组

(One for each field in the table) 
Byte    Contents    Description
0-31    32 bytes    Field name in ASCII (zero-filled).
32      1 byte      Field type in ASCII (B, C, D, N, L, M, @, I, +, F, 0 or G).
33      1 byte      Field length in binary.
34      1 byte      Field decimal count in binary.
35-36   2 bytes     Reserved.
37      1 byte      Production .MDX field flag; 0x01 if field has an index tag in the production .MDX file; 0x00 if the field is not indexed.
38-39   2 bytes     Reserved.
40-43   4 bytes     Next Autoincrement value, if the Field type is Autoincrement, 0x00 otherwise.
44-47   4 bytes     Reserved.

实施例

;04 = 4 for dBASE Level 7
;75 02 10 = Date of last update; in YYMMDD
;DF = 223 number of record

; 0  1  2  3  4  5  6  7   8  9 10 11 12 13 14 15

 04 75 02 10 DF 00 00 00  15 03 B6 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 44 42 57 49 4E 55 53 30  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00

;Column name start from 68 offset (Need to convert from hex to ascii)
;http://www.rapidtables.com/convert/number/hex-to-ascii.htm
;Example, 53 49 54 45  4E 4D = SITENM

;64 65 66 67 68 69 70 71  72 73 74 75 76 77 78 79
;            00 01 02 03 04  05 06 07 08 09 10 11  

 00 00 00 00 53 49 54 45  4E 4D 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00

;(See 1.2 Field Descriptor Array) 
;0-31 = Field name in ASCII (zero-filled)
;32   = Field type in ASCII 
;From below example the field type is 43 which is equal to 'C' in ascii
;33   = Field length in binary.
;From below example the field length is 0A which is equal to '10' in decimal
;28 29 30 31 32 33 34 35  36 37 38 39 40 41 42 43

 00 00 00 00 43 0A 00 00  00 00 00 00 00 00 00 00

;Column will start from 00 and end in offset 47 (total 48 bytes until it readched '0D' Field Descriptor terminator)
;So below 00 is start with another column 
;Example, 44 41 54 45 = DATE  

;44 45 46 47 00 01 02 03 04  05 06 07 08 09 10 11

 00 00 00 00 44 41 54 45  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 0A 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 54 49 4D 45  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 08 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 54 52 41 4E  53 5F 43 4F 44 45 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 02 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 54 52 41 4E  53 5F 44 45 53 43 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 1E 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 42 55 53 4E  4F 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 02 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 55 4E 49 54  4E 4F 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 02 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 52 45 41 44  45 52 4E 4F 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 02 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 4F 4E 54  4E 41 4D 45 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 0C 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 44 52 4E 41  4D 45 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 0C 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 41 52 44  4E 4F 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 06 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 4E 41 4D 45  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 23 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 44 45 50 54  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 0C 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 4A 4F 42 00  00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 0C 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 49 46 49 45  4C 44 00 00 00 00 00 00
 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 43 1A 00 00  00 00 00 00 00 00 00 00
 00 00 00 00 0D -> Here is the Field Descriptor terminator '0D'
```

使用十六进制查看器检查dbase版本

1 个答案: