我有一个SearchStringTooltip
ManagedObject。具有属性@dynamic tooltipText;
(NSString)
我需要在数据库中动态添加新的工具提示,但是我只需要唯一值(不敏感)。
它们一次可以超过100个。并且每次我检查唯一性..
看起来像:
if (newTooltips.count == 0)
return;
NSEntityDescription *entity = [NSEntityDescription
entityForName:@"SearchStringTooltip"
inManagedObjectContext:self.moc];
NSFetchRequest *request = [NSFetchRequest new];
[request setEntity:entity];
for (NSString *name in newTooltips) {
[request setPredicate:[NSPredicate predicateWithFormat:@"tooltipText = %@", name]]; //like = (=) + time *2(sometimes *3) ofcourse i know i need like.. Its insensitive
NSInteger count = [self.moc countForFetchRequest:request error:nil]; //But its is very expensive operation expensive
if (count > 0) {
continue;
}
DBSearchStringTooltip *tooltip = [NSEntityDescription insertNewObjectForEntityForName:@"SearchStringTooltip"
inManagedObjectContext:self.moc];
tooltip.tooltipText = name;
}
如何才能更便宜地进行存储?可以有超过10 000个工具提示来检查唯一性...我必须全部检查它们。
最佳答案
快速回答,我相信会更有效率。使用以下代码片段而不是循环:
[request setPredicate:[NSPredicate predicateWithFormat:@"tooltipText IN %@", newTooltips]];
[request setResultType:NSDictionaryResultType];
[request setPropertiesToFetch:@[@"tooltipText"]];
NSArray* result = [self.moc executeFetchRequest:request error:nil];
NSArray* existingTooltipNames = [result valueForKey:@"tooltipText"];
NSMutableOrderedSet* itemsToAdd = [NSMutableOrderedSet orderedSetWithArray:newTooltips];
[itemsToAdd minusSet:[NSSet setWithArray:existingTooltipNames]];
for (NSString *name in itemsToAdd) {
DBSearchStringTooltip *tooltip = [NSEntityDescription insertNewObjectForEntityForName:@"SearchStringTooltip" inManagedObjectContext:self.moc];
tooltip.tooltipText = name;
}
关于ios - 验证ManagedObject,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/15529487/