Encrypt existing database

[zeeshan-i-pathan]

If i try to encrypt an existing database it gets corrupted and gives the file is encrypted or is not a database error is there no export feature for this case. I tried modifying the code to something like.

   // for opening the database
    boolean bExist;
    boolean encrypted;
    int nRes;
      if( CRhoFile::isFileExist(strDbPath.c_str()) && checkImportState) {
        encrypted = false;
        bExist = CRhoFile::isFileExist((strDbPath).c_str());
        nRes = sqlite3_open((strDbPath).c_str(),&m_dbHandle);
        LOG(INFO)+"Opening without encryption";
      } else {
        encrypted = true;
        bExist = CRhoFile::isFileExist((strDbPath+"_enc").c_str());
        nRes = sqlite3_open((strDbPath+"_enc").c_str(),&m_dbHandle);
        LOG(INFO)+"Opening with encrypted";
      }

   // for the PRAGMA call
    if ( szEncrypt && strcmp(szEncrypt, "1") == 0 && encrypted)

  // and finally after all that 
    if( !encrypted )
    {
      String strCreate = "select name from sqlite_master where type='table' and name!='sqlite_seqeunce' and rootpage>0;";
      IDBResult res = executeSQL( strCreate.c_str() );
      CDBAdapter db(m_strDbPartition.c_str(), true);
      // this db opens with the pragma call as i have put logs there to be sure
      db.open( strDbPath, m_strDbVer, true, false ); 
      db.startTransaction(); # all this also works fine 
      for ( ; !res.isEnd(); res.next() ) {
        String createTableStatement = res.getStringByIdx(0);
        LOG(INFO)+"copying table "+createTableStatement;
        copyTable( createTableStatement, *this, db );
      }
      db.endTransaction();
      db.close();
      close(false);
      CRhoFile::deleteFile(strDbPath.c_str());
      // here the strDbPath_enc database that is opened still gives the file is encrypted or not a database error.
      open( strDbPath, m_strDbVer, false, false ); 
    }