Hi,

My application is working with a document file implemented in a sqlite database.
So, the function "Open" is copying a file base sqlite database in memory (This is very fast).
The function "Save" is copying a memory database into a file (This is very slow due to file access).

For you information, here is the code to do this copy:
Qt Code: 
  1. SKGError SKGServices::copySqliteDatabase(QSqlDatabase* iFileDb, QSqlDatabase* iMemoryDb, bool iFromFileToMemory)
  2. {
  3.     SKGError err;
  4.     SKGTRACEINRC(10, "SKGServices::copySqliteDatabase", err);
  5.     if (iFileDb && iMemoryDb) {
  6.         SKGTRACEL(20) << "Input parameter [iFileDb]=[" << iFileDb->databaseName() << ']' << endl;
  7.         SKGTRACEL(20) << "Input parameter [iMemoryDb]=[" << iMemoryDb->databaseName() << ']' << endl;
  8.         SKGTRACEL(10) << "Input parameter [iFromFileToMemory]=[" << (iFromFileToMemory ? "FILE->MEMORY" : "MEMORY->FILE") << ']' << endl;
  9.  
  10.         QString dbFileName=iFileDb->databaseName();
  11.  
  12.         // Copy the schema
  13.         SKGTRACEL(20) << "Coping the schema..." << endl;
  14.         SKGStringListList listSqlOrder;
  15.         err=SKGServices::executeSelectSqliteOrder((iFromFileToMemory ? iFileDb: iMemoryDb),
  16.                 "SELECT sql FROM sqlite_master WHERE sql NOT NULL and name NOT IN ('sqlite_stat1', 'sqlite_sequence')",
  17.                 listSqlOrder);
  18.  
  19.         int nb=listSqlOrder.count();
  20.         for (int i=1; err.isSucceeded() && i<nb; ++i) { //Forget header
  21.             QString val=listSqlOrder.at(i).at(0);
  22.             err=SKGServices::executeSqliteOrder((iFromFileToMemory ? iMemoryDb: iFileDb), val);
  23.         }
  24.  
  25.         // Attach the file dbFileName to the target
  26.         if (err.isSucceeded()) {
  27.             SKGTRACEL(20) << "Attaching the file..." << endl;
  28.             err = SKGServices::executeSqliteOrder(iMemoryDb, "ATTACH DATABASE '" + dbFileName + "' as source");
  29.             if (err.isSucceeded()) {
  30.                 // Copy the DATA from the source to the target
  31.                 SKGTRACEL(20) << "Coping data..." << endl;
  32.                 err = SKGServices::executeSqliteOrder(iMemoryDb, "BEGIN");
  33.                 if (err.isSucceeded()) {
  34.                     SKGStringListList listSqlOrder;
  35.                     err=SKGServices::executeSelectSqliteOrder(iMemoryDb,
  36.                             "SELECT name FROM source.sqlite_master WHERE type='table' and name NOT IN ('sqlite_stat1', 'sqlite_sequence')",
  37.                             listSqlOrder);
  38.                     int nb=listSqlOrder.count();
  39.                     for (int i=1; err.isSucceeded() && i<nb; ++i) { //Forget header
  40.                         QString val=listSqlOrder.at(i).at(0);
  41.                         if (iFromFileToMemory)  err=SKGServices::executeSqliteOrder(iMemoryDb, "insert into main."+val+" select * from source."+val);
  42.                         else  err=SKGServices::executeSqliteOrder(iMemoryDb, "insert into source."+val+" select * from main."+val);
  43.                     }
  44.  
  45.                 }
  46.                 if (err.isSucceeded())  err = SKGServices::executeSqliteOrder(iMemoryDb, "COMMIT");
  47.  
  48.                 //Detach
  49.                 SKGError err2=SKGServices::executeSqliteOrder(iMemoryDb, "DETACH DATABASE source");
  50.                 if (err.isSucceeded() && err2.isFailed()) err=err2;
  51.  
  52.                 //Check if created file exists
  53.                 if (err.isSucceeded() && !iFromFileToMemory && !QFile(dbFileName).exists()) {
  54.                     //Set error message
  55.                     err.setReturnCode(ERR_FAIL);
  56.                     err.setMessage(i18nc("An error message", "Creation file [%1] failed",dbFileName));
  57.                 }
  58.             }
  59.         }
  60.         if (err.isFailed()) err.addError(SQLLITEERROR + ERR_FAIL, i18nc("Error message", "%1 failed", QString("copySqliteDatabase::copySqliteDatabase()")));
  61.     }
  62.     return err;
  63. }
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I saw in this page http://www.sqlite.org/backup.html that new APIs are existing to do that.

Do you know how we can use it with QT ?