How can i perform a PFRelation query using parse in ios - ios

Question

I have created a relation between two tables
LocationClass Table In this table i have a column with location images with the relation of another table ie., Assets
![This is location Class Image, If user selected a locationName, need to get the locationImages(viewRelation)][1]
Assets Table, It contains Images for each relation Now my query is how to get the data from relation database. Here if user select a location means i need to get a group of images for the relevant location ![This is my Assets Table, here need to retrieve the images based on the selected location from the locationClass Table][2]
Till now, I have done with this format
PFQuery *queryObj = [PFQuery queryWithClassName:#"LocationClass"];
sharedDelegate = (AppDelegate *)[[UIApplication sharedApplication]delegate];
// Run the query
[queryObj whereKey:#"locationImages" equalTo:[PFObject objectWithoutDataWithClassName:#"Assets" objectId:#"aAPzhdO4w6"]];
[queryObj findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error)
{
[locationArray addObjectsFromArray:objects];
sharedDelegate.locationsArray = locationArray;
[locationDropDown reloadData];
}
}];
In my location array for a single object contain
<__NSArrayM 0xaee4eb0>(
<LocationClass:ZtOP9voUak:(null)> {
LocationId = WilliamsBurgId;
LocationName = WilliamsBurg;
locationImages = "<PFRelation: 0xaf53c30>(<00000000>.(null) -> Assets)";
}
)

Answer 1

Solution for to pass the data from PFRelation Object
// should pass the main table name
PFQuery *query = [PFQuery queryWithClassName:#"LocationClass"];
// should pass object id for the selected row
PFObject *getImageObject = [query getObjectWithId:#"need to pass object id from the maintable"];
locationImagesArray = [[NSMutableArray alloc]init];
// To acess the data from the relation object
PFRelation *relationObj = [getImageObject relationForKey:#"locationImages"];
PFQuery *query1 = [relationObj query];
[query1 findObjectsInBackgroundWithBlock:^(NSArray *results, NSError *error) {
[locationImagesArray addObjectsFromArray:results];
for (int imgCount = 0; imgCount < [locationImagesArray count]; imgCount ++) {
PFFile *getImage1 = [[locationImagesArray valueForKey:#"Image"] objectAtIndex:imgCount];
[getImage1 getDataInBackgroundWithBlock:^(NSData *imageData, NSError *error)
{
if (imageData!=nil) {
UIImage *image = [UIImage imageWithData:imageData];
activityImage.image = image;
NSLog(#"location image output");
NSLog(#"location image output : %#", activityImage.image);
}
}];
}