CoreData 简单使用

CoreData：封装了Sqlite数据库的系统自带框架。

常用方法

@property(nonatomic,strong)NSArray *persons;

1、查询数据：

XYZAppDelegate * app = [UIApplicationsharedApplication].delegate;

NSFetchRequest *request = [[NSFetchRequestalloc]initWithEntityName:@"Person"];

self.persons = [app.managedObjectContextexecuteFetchRequest:request error:nil];

   （1）设置排序

    NSSortDescriptor *sort = [NSSortDescriptorsortDescriptorWithKey:@"name"ascending:YES];

    [request setSortDescriptors:@[sort]];

    sortDescriptorWithKey表示排序字段

  （2）设置查询条件

    NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"name == ‘XYZ'"];

    [request setPredicate:predicate];

2、插入数据

Person *person = [NSEntityDescriptioninsertNewObjectForEntityForName:@"Person"inManagedObjectContext:app.managedObjectContext];

person.name =self.nameText.text;

person.mobileNum =self.MobileNumText.text;

[app saveContext];

3、修改数据

self.person.name = self.nameText.text;

self.person.mobileNum = self.MobileNumText.text;

[app  saveContext];

4、删除数据  

[app.managedObjectContextdeleteObject:self.persons[indexPath.row]];

[app saveContext];