Core Data 多表连接及查询

一：先建议两张表

Person,Score 分别代表，学生表，分数表
在 Person的Relationships里面建立关系，指向分数score

二：coreData生成的两个表：

Person

@class Score;

@interface Person : NSManagedObject

@property (nonatomic, retain) NSString * address;

@property (nonatomic, retain) NSNumber * age;

@property (nonatomic, retain) NSString * name;

@property (nonatomic, retain) Score *score;

@end

　　Score

@interface Score : NSManagedObject

@property (nonatomic, retain) NSNumber * dotNet;

@property (nonatomic, retain) NSNumber * java;

@property (nonatomic, retain) NSNumber * php;

@end

三：添加记录查询记录代码

- (void)addTheRowData

{

    Person *person = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:self.appDelegate.managedObjectContext];

    person.name = @"李四";

    person.age = [NSNumber numberWithInt:];

    person.address = @"中国济南";

    Score *score = [NSEntityDescription insertNewObjectForEntityForName:@"Score" inManagedObjectContext:self.appDelegate.managedObjectContext];

    score.dotNet = [NSNumber numberWithFloat:70.77];

    score.php = [NSNumber numberWithFloat:80.88];

    score.java = [NSNumber numberWithFloat:90.99];

    person.score = score;

    //score.person = person;

    [self.appDelegate saveContext];

}

- (void)showTheTableData

{

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]initWithEntityName:@"Person"];

    NSError *error;

    NSArray *fetchedObjects = [self.appDelegate.managedObjectContext executeFetchRequest:fetchRequest error:&error];

    for (Person *info in fetchedObjects) {

        //Score *score = info.score;

        NSLog(@"name:%@ age:%@ address:%@ --- dotNet:%@ java:%@ php:%@", info.name,info.age,info.address,info.score.dotNet,info.score.java,info.score.php);

    }

}

巴特西

Core Data 多表连接及查询

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