离线Geodatabase该如何读取？

AGSGDBGeodatabase *gdb = [AGSGDBGeodatabase geodatabaseWithName:@paris error:nil];



self.localFeatureTable = [[gdb featureTables] objectAtIndex:0];

self.localFeatureTableLayer = [[AGSFeatureTableLayer alloc] initWithFeatureTable:self.localFeatureTable];



[self.mapView addMapLayer:self.localFeatureTableLayer withName:@Offline Feature Layer];