Subquery and IN Statement in realm - ios

Question

I have three realm objects. Department, section and user. section is a kind of sub department in a department. But there will be users under each section and each department.
#interface Department : RLMObject
#property NSString *name;
#property BOOL isCollapsed;
#property (nonatomic, strong) RLMArray<Section> *sections;
#property (nonatomic, strong) RLMArray<User> *users;
#end
#interface Section : RLMObject
#property NSString *name;
#property BOOL isCollapsed;
#property RLMArray<User> *users;
#end
#interface User : RLMObject
#property NSString *department;
#property NSString *email;
#property NSString *firstname;
#property NSString *lastname;
#property NSString *fullname;
#end
What i want to do is, I want to search all the user whose first name and last name contains "a" and linked with department and section.
Now what i am doing is
searchText = [searchText lowercaseString];
RLMResults *sections = [Section objectsWhere:
[NSString stringWithFormat:#"SUBQUERY(users, $user, $user.fullname contains '%#' OR $user.nickname contains '%#').#count > 0",searchText,searchText]];
NSMutableArray *sectionNames = [NSMutableArray array];
for (Section *section in sections)
{
[sectionNames addObject:section.name];
}
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SUBQUERY(sections, $section, $section.name IN %#).#count > 0", sectionNames];
RLMResults *filteredDepartments = [[Department objectsWithPredicate:predicate] sortedResultsUsingProperty:#"name" ascending:YES];
NSPredicate *pred = [NSPredicate predicateWithFormat:#"SUBQUERY(users, $user, $user.fullname contains %# OR $user.nickname contains %#).#count > 0",searchText,searchText];
RLMResults *departments = [filteredDepartments objectsWithPredicate:pred];
Right now the issue is there is two sections in sections array but in the deparments results, it returns null. please help. thanks.
Note: If one user already belongs to section then that user will not be include in department.

Answer 1

Maybe you do not need to use subquery. More simply, you can use ANY in query like the following:
[Department objectsWhere:
#"ANY users.firstname CONTAINS %# OR ANY users.lastname CONTAINS %# OR ANY sections.users.firstname CONTAINS %# OR ANY sections.users.lastname CONTAINS %#", searchText, searchText, searchText, searchText];
But I think using inverse relationships is more easier. In Realm, inverse relationships is defined with RLMLinkingObjects.
You can add inverse relationships to User class as follows:
#interface User : RLMObject
...
#property (readonly) RLMLinkingObjects *departments;
#property (readonly) RLMLinkingObjects *sections;
#end
#implementation User
+ (NSDictionary *)linkingObjectsProperties {
return #{#"departments": [RLMPropertyDescriptor descriptorWithClass:Department.class propertyName:#"users"],
#"sections": [RLMPropertyDescriptor descriptorWithClass:Section.class propertyName:#"users"]};
}
#end
Then you can get departments and sections where the user belongs to from User's property, like the following:
RLMResults *users = [User objectsWhere:#"firstname CONTAINS %# OR lastname CONTAINS %#" , searchText, searchText];
for (User *user in users) {
NSLog(#"%#", user.departments);
NSLog(#"%#", user.sections);
}