Question

我想在函数下使用.mm文件来处理核心数据

//在头文件中

/*Saving parameters*/
NSManagedObjectModel *managedObjectModel;
NSManagedObjectContext *managedObjectContext;       
NSPersistentStoreCoordinator *persistentStoreCoordinator;

NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];


NSManagedObjectContext *context = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];


/* 1. Check if employee exists*/


NSEntityDescription *employeeentity = [NSEntityDescription 
                               entityForName:@"employees" inManagedObjectContext:context];
[fetchRequest setEntity:employeeentity];
NSError *error;
NSArray* employee_info = [context executeFetchRequest:fetchRequest error:&error];


if (employee_info !=nil) {

    NSLog(@"employee Exist");



}
else {

    NSLog(@"employee NOT Exist");

}

我使用mm因为我也使用cpp也有任何建议

祝你好运

Answer 1

我根本不是C ++人。但如果我被允许做出有根据的猜测：

对我而言，听起来好像编译器不知道NSPersistentStoreCoordinator是什么所以你应该包含标题<CoreData/CoreData.h>或者告诉他这个类存在的C ++等价于@class NSPersistentStoreCoordinator

ISO C ++禁止声明'NSPersistentStoreCoordinator'没有类型

1 个答案: