[英]How to find the maximum value of date stored in coredata?
我在coredata中創建了一個實體,它包含類型為Date的屬性。 所以我怎么能找到存儲在那里的日期的最大值。
NSString * yourEntityName = @"Entity";
NSString * yourDateAttributeName = @"date";
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:yourEntityName
inManagedObjectContext:ctx];
[fetchRequest setEntity:entity];
[fetchRequest setPropertiesToFetch:@[yourDateAttributeName]];
[fetchRequest setFetchLimit:1];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:yourDateAttributeName ascending:NO];
NSArray *sortDescriptors = @[sortDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
NSError * error = nil;
NSArray * results = [ctx executeFetchRequest:fetchRequest error:&error];
NSManagedObject * yourEntityObject = [results firstObject];
NSDate * date = [yourEntityObject valueForKey:yourDateAttributeName];
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.