Error Copying DBF/MDX files - delphi

Question

I use the following code to copy dbf/mdx files from one folder to another:
procedure TfrmMain.MyCopyFile(S1, S2: string);
begin
if not FileExists(S2) then
CopyFile(PCHAR(S1), PCHAR(S2), true)
else
if Application.MessageBox(PCHAR('Overwrite existing file ' + S2 + '?'), 'File exists in folder',MB_YESNO + MB_DEFBUTTON1) = IDYES
then CopyFile(PCHAR(S1), PCHAR(S2), false)
end;
The code works fine when table name stays the same.
If I change the name of the table:
MyCopyFile(CurPath + '\orders.dbf', NewPath + '\ordly.dbf');
MyCopyFile(CurPath + '\orders.mdx', NewPath + '\ordly.mdx');
When I try to open ordly.dbf I get an error message:
Corrupt table/index header.
File: C:\DATA\2011\ORDLY.MDX

Answer 1

the problem is due to the mdx format stores inside the name of the data file associated (table name). because that when you rename a mdxfile the index still points to the old name of data file.
check this link to see the structure of the mdx file.
The Structure of Multiple Index files (*.mdx)
0 | Version number *1| ^
|-----------------------| |
1 | Date of creation | |
2 | YYMMDD | |
3 | | |
|-----------------------| |
4 | Data file name | File
5 | (no extension) | Header
: : |
: : |
19 | | |
|-----------------------| |
20 | Block size | |
| | |
|-----------------------| |
22 | Block size adder N | |
| | |
|-----------------------| |
24 | Production index flag | |
|-----------------------| |
25 | No. of entries in tag | | *2
|-----------------------| |
26 | Length of tag | | *3
|-----------------------| |
27 | (Reserved) | |
|-----------------------| |
28 | No.of tags in use | |
| | |
|-----------------------| |
30 | (Reserved) | |
| | |
|-----------------------| |
32 | No.of pages in tagfile| |
| | |
| | |
35 | | |
|-----------------------| |
36 | Pointer to first free | |
| page | |
| | |
39 | | |
|-----------------------| |
40 | No.of block available | |
| | |
| | |
43 | | |
|-----------------------| |
44 | Date of last update | |
| YYMMDD | |
46 | | |
|-----------------------| |
47 | (Reserved) | |
|-----------------------| |
48 | (Garbage) | |
: : |
: : |
| | | ___|=======================|
543| | _V___ / 0 | Tag header page no. |
|-----------------------| | / | |
544| Tag table entries | Tag / | |
| | Table | 3 | |
:.......................: | | |-----------------------| Tag
: : | | 4 | Tag name | table
:.......................: | | : :
: : | / : :
: : | / | |
:.......................:__|_/ 14 | |
: : | |-----------------------|
: : | 15 | Key format *4 |
: : | |-----------------------|
:.......................:__|_ 16 | Forward tag thread (<)|
: : | \ |-----------------------|
: : | \ 17 | Forward tag thread (>)|
: : | \ |-----------------------|
: : | | 18 | Backward tag thread *5|
| | | | |-----------------------|
| | | | 19 | (Reserved) |
M*N| |__V__ | |-----------------------|
|=======================| ^ | 20 | Key type *6 |
0| Pointer to root page | | | |-----------------------|
| | | | 21 | (Reserved) |
| | | | : :
3| | | | : :
|-----------------------| | | 31 | |
4| File size in pages | Tag | |-----------------------|
| | header| 32 | (Garbage) |
| | | | : :
7| | | | | |
|-----------------------| | \ N | |
8| Key format *7 | | \____|=======================|
|-----------------------| |
9| Key type *8 | |
|-----------------------| |
10| (Reserved) | |
| | |
|-----------------------| |
12| Index key length *9 | |
| | |
|-----------------------| |
14| Max.no.of keys/page | |
| | |
|-----------------------| |
16| Secondary key type *10| |
| | |
|-----------------------| |
18| Index key item length | |
| | |
|-----------------------| |
20| (Reserved) | |
| | |
| | |
|-----------------------| |
23| Unique flag | |
|-----------------------| |
| | |
: : |
: :__V__
N*M|=======================|