[Qt-interest] Compressing sqlite file with QtIOCompressor results in corrupted db

[Tony Rietwyk]

> -----Original Message-----
> Sent: Monday, 6 September 2010 21:26
> Hi all,
> 
> I am compressing/uncompressing a sqlite db file with QtIOCompressor.
> 
> The file size seems to be ok after uncompressing and I am 
> able to open 
> the database but any query will fail with: "File is encrypted 
> or not a 
> database".
> Do I need to set any other options?
> 
> This is the code:
> 
> //compressing
> QFile fileIn("in");
> fileIn.open(QIODevice::ReadOnly);
> QByteArray ba = fileIn.readAll();
> 
> QFile outFile("out");
> QtIOCompressor compressor(&outFile);
> compressor.open(QIODevice::WriteOnly);
> compressor.write(ba);
> compressor.close();
> 
> //uncompressing
> QFile compsqlite("out");
> QFile sqlite("sqlite");
> 
> QtIOCompressor compressor(compsqlite);
> compressor.open(QIODevice::ReadOnly);
> const QByteArray ba = compressor.readAll();
> 
> sqlite.open(QIODevice::WriteOnly);
> QDataStream out(&sqlite);
> 
> compressor.close();
> out << ba;
> 
> 
> Jan


Hi Jan, 

QDataStream is a file format private to Qt applications.  So sqlite won't
know about it.  

I suggest to use sqlite.write(ba) to mirror the readAll that you did on the
"in" file. 

Tony.