How to manage local landmark databases
Article Metadata
All landmarks and categories are stored in databases, which may be local or remote. The primary identifier of the database is URI. The URI consists of a protocol specifier and the database location: "protocol://location".
For the local database:
- protocol is "file".
- location consists of disk drive and file name (with extension *.ldb)
Example of the local database URI: "file://C:my_data.ldb"
You can use Landmarks Database Management API for the database management. The main class of this API is CPosLmDatabaseManager. (include epos_cposlmdatabasemanager.h, link against eposlmdbmanlib.lib)
A couple of small examples:
The following code snippet demonstrates how to rename default landmark database:
_LIT( KNewName, "New Database Name" );
const TInt KMaxDbNameLen = 64;
TBuf<KMaxDbNameLen> newName( KNewName );
// Main DB Manager;
CPosLmDatabaseManager* dbManager = CPosLmDatabaseManager :: NewL();
CleanupStack :: PushL( dbManager );
// Get default db URI
HBufC* defaultUri = dbManager->DefaultDatabaseUriLC();
if( defaultUri )
{
// Get db info by URI
HPosLmDatabaseInfo* dbInfo = HPosLmDatabaseInfo :: NewLC( *defaultUri );
dbManager->GetDatabaseInfoL( *dbInfo );
// Get settings from info
TPosLmDatabaseSettings& settings = dbInfo->Settings();
// Set new name and save settings
settings.SetDatabaseName( newName );
dbManager->ModifyDatabaseSettingsL( *defaultUri, settings );
CleanupStack :: PopAndDestroy( 2 ); // dbInfo defaultUri
}
CleanupStack :: PopAndDestroy( 1 ); // dbManager
The following code snippet demonstrates how to copy all local databases from one drive to another:
// db manager;
CPosLmDatabaseManager* dbManager = CPosLmDatabaseManager :: NewL();
CleanupStack :: PushL( dbManager );
// protocol for the local DB
_LIT( KFileProto, "file" );
// array, that contains URI of the local DBs
CDesCArray* dbUriList = dbManager->ListDatabasesLC( KFileProto );
const TInt KMaxUriLen = 128;
TBuf<KMaxUriLen> uri, newUri;
TChar driveFrom = 'C',
driveTo = 'E';
TBuf<1> newDrive;
newDrive.Append( driveTo );
for(TInt i = 0; i < dbUriList->Count(); i++ )
{
uri = (*dbUriList)[i];
if( uri[7] == driveFrom )
{
// setup new URI: file://C... -> file://E...
newUri = uri;
newUri.Replace( 7, 1, newDrive );
// check if such DB exists
if( dbManager->DatabaseExistsL( newUri ) )
{
// delete if already exists
dbManager->DeleteDatabaseL( newUri );
}
dbManager->CopyDatabaseL( uri, newUri );
}
}
CleanupStack :: PopAndDestroy( 2 ); // iDbList dbManager
