Backing up SQLite database from a program
lazarus / 16-Databases

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JanRoza · 2010-07-09 20:42

Has anyone an example of how to make a backup of a SQLite database
from a program that has the database opened?
A simple CopyFile doesn't work as the active program apparently has a
lock on the file.
I saw some examples on the SQLite website but they are in C which I'm
not too familiar with.

Thanks!

Jan

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theo · 2010-07-09 21:02

If you have a look at CopyFile implementation, you see that the SrcFS
is created with fmShareDenyWrite.
This is probably to prevent that the file is being written while you
copy it.
http://www.freepascal.org/docs-html/rtl/sysutils/fmsharedenywrite.html
You may try to copy this code using
http://www.freepascal.org/docs-html/rtl/sysutils/fmsharedenynone.html

Good luck!

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JanRoza · 2010-07-11 16:47

That indeed was the solution.
I used the following code and that worked like clockwork:

Code: [Select]Procedure TfrmMain.CopyFile(Source: String; Dest:
string);
var
  SourceStream, DestStream: Classes.TFileStream; // source and dest
file streams
Begin
  DestStream := nil;

  // Open source and dest file streams
  SourceStream := Classes.TFileStream.Create(Source,
SysUtils.fmOpenRead or SysUtils.fmShareDenyNone); 
 // original used SysUtils.fmShareDenyWrite

  try
    DestStream := Classes.TFileStream.Create(Dest, Classes.fmCreate or
SysUtils.fmShareExclusive);

    // Copy file from source to dest
    DestStream.CopyFrom(SourceStream, SourceStream.Size);

    // Set dest file's modification date to same as source file
    SysUtils.FileSetDate(DestStream.Handle,
SysUtils.FileGetDate(SourceStream.Handle));
  finally
    // Close files
    DestStream.Free;
    SourceStream.Free;
  end;
End;

So one more SQLite riddle solved, I'm beginning to like SQLite more
and more