C++ CDbColSet::Col方法代码示例

/**
Alters the "Event" table if the the table does not have "SimId" column.
@return KErrNone, The "alter" operation has completed successfully, system wide or database specific error code otherwise.  
@leave  KErrNoMemory, an out of memory condition has occurred;
                      Some other failure codes, not related to the "alter" opertaion.
*/
TInt CLogServDatabaseMarshall::AlterEventTblIfNoSimIdL(CDbColSet& aEventTblColSet)
    {//Compiled only when SYMBIAN_ENABLE_EVENTLOGGER_DUALSIM macro is defined
    const TDbCol* simIdCol = aEventTblColSet.Col(KLogFieldEventSimId);
    TInt err = KErrNone;
    if(!simIdCol)
        {
        TDbCol col(KLogFieldEventSimId, EDbColUint32);
        aEventTblColSet.AddL(col);
        err = iDatabase.AlterTable(KLogNameEventString, aEventTblColSet);
        }
    return err;
    }

/**
Alters the "Event" table if the number column length is not KLogMaxNumberLength.
@return KErrNone, The "alter" operation has completed successfully, system wide or database specific error code otherwise.  
*/
TInt CLogServDatabaseMarshall::AlterEventTblIfOldFmt(CDbColSet& aEventTblColSet)
    {
    const TDbCol* numberCol = aEventTblColSet.Col(KLogFieldEventNumberString);
    __ASSERT_DEBUG(numberCol != NULL, User::Invariant());
    TInt err = KErrNone;
    // check the column width is correct
    if(numberCol->iMaxLength != KLogMaxNumberLength)
        {
        //The column width is not correct, so this is an old format database.
        //Modify the database so the number length is KLogMaxNumberLength.
        (const_cast <TDbCol*> (numberCol))->iMaxLength = KLogMaxNumberLength;
        err = iDatabase.AlterTable(KLogNameEventString, aEventTblColSet);
        }
    return err;
    }

TBool ExtHintFieldExistsL(RFs& theFS)
	{
	TBool theResult;
	RDbNamedDatabase theDatabase;
	
	TestNoErrL(theDatabase.Open(theFS, KDatabaseFileName,KCntDbSecureFormat));

	CDbColSet* theIdentitiTable = theDatabase.ColSetL(KIdentityTableName);
	CleanupStack::PushL(theIdentitiTable);
	const TDbCol* theExtHint = theIdentitiTable->Col(KContactExtHintField);
	theResult = (theExtHint != NULL); //The field shouldn't exits

	CleanupStack::PopAndDestroy(); //theIdentitiTable
	theDatabase.Close();

	return theResult;
	}

void CLogServDatabaseMarshall::MakeColumnAutoIncremetingL(const TDesC& aTable, const TDesC& aColumn)
	{
	CDbColSet* newTable = iDatabase.ColSetL(aTable);
	CleanupStack::PushL(newTable);

	const TDbCol* oldCol = newTable->Col(aColumn);
	__ASSERT_DEBUG(oldCol != NULL, Panic(ELogNoSuchColumn));

	TDbCol newCol = *oldCol;
	newCol.iAttributes |= TDbCol::EAutoIncrement;

	newTable->Remove(aColumn);
	newTable->AddL(newCol);

	User::LeaveIfError(iDatabase.DropTable(aTable));
	User::LeaveIfError(iDatabase.CreateTable(aTable, *newTable));
		
	CleanupStack::PopAndDestroy(newTable);
	}