CoreData记录1

CoreData存储字典数组

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1：在Entity Attribute中属性类型选择Transformable
2: 然后右侧Transformer写上一个类名，之后创建类文件需要用这个类名和属性对应上
3: 创建一个继承NSValueTransformer的类FloderIds 在类里写上归档的代码

+ (Class)transformedValueClass
{
    return [NSArray class];
}
+ (BOOL)allowsReverseTransformation
{
    return YES;
}
- (id)transformedValue:(id)value {
    //转换成NSData保存到数据库
    return [NSKeyedArchiver archivedDataWithRootObject:value requiringSecureCoding:YES error:nil];
}
- (id)reverseTransformedValue:(id)value
{
    return [NSKeyedUnarchiver unarchivedObjectOfClass:[NSArray class] fromData:value error:nil];
}

之后可以正常使用了

  - (void)insertFlodersEntity
{
    for (int i = 0; i < 50; i++) {
        UserFloderEntity *floderEntity = [NSEntityDescription insertNewObjectForEntityForName:@"UserFloderEntity" inManagedObjectContext:self.context];
        floderEntity.id = 200000 + I;
        floderEntity.uid = 100000 + I;
        NSArray *fids = @[@(200000+i),@(200000+i+1),@(200000+i+2),@(200000+i+3),@(200000+i+4),@(200000+i+5)];
        floderEntity.fids = fids;
        floderEntity.status = NO;
    }
    [self saveContext];
}
- (void)fetchFloderEntity
{
    NSFetchRequest *floderEntityRequest = [UserFloderEntity fetchRequest];
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"id > %d",0];
    [floderEntityRequest setPredicate:predicate];
    
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"id" ascending:YES];
    [floderEntityRequest setSortDescriptors:[NSArray arrayWithObjects:sortDescriptor,nil]];
    
    NSError *error = nil;
    NSArray *fetchedObjects = [_context executeFetchRequest:floderEntityRequest error:&error];
    UserFloderEntity *floder = [fetchedObjects lastObject];
    NSArray *arr = (NSArray*)floder.fids;
    NSLog(@"%d %@",floder.id,arr);
}

CoreData生成实体类文件

需要在CoreData.storyboard中需要生成的实体，右边属性栏里Codegen中选择Manual/none 不然系统生成一份代码，自己生成一份代码会重复

Relationships

关联实体 WeChate7388b394418abbcd5317c097c5b4e07.png

图中红框1
Destination:代表关联的实体，
Inverse：代表被关联的实体中反向关联的数据
红框2中
Delete Rule：代表删除规则，即在一个实体中删除，会不会在关联的实体中表现出来，一般选Nullify，会自动管理，如果一个关联属性是一对多，或者多对多。往一个实体中的属性添加值，另一个属性也会体现出来。

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如果Codegen中选择Manual/None，不自动生成代码，则需要我们在Editor中选择Create ManagerObject subclass 手动生成实体文件，并且实现几个添加属性和删除属性的方法， WeChat012e0e5e4273b715dd4d84498b26bcd1.png

其中红框的几个方法是没有实现的，需要在m文件中实现如下

#import "FileEntity+CoreDataProperties.h"

@implementation FileEntity (CoreDataProperties)

+ (NSFetchRequest<FileEntity *> *)fetchRequest {
    return [NSFetchRequest fetchRequestWithEntityName:@"FileEntity"];
}

@dynamic id;
@dynamic name;
@dynamic length;
@dynamic star;
@dynamic data;
@dynamic last_read_position;
@dynamic last_open_time;
@dynamic create_time;
@dynamic status;
@dynamic infloder;

@end
@implementation FileEntity (CoreDataGeneratedAccessors)

- (void)addInfloderObject:(FloderEntity *)value
{
    NSMutableSet *inFloder = [self.infloder mutableCopy];
    [inFloder addObject:value];
    self.infloder = inFloder;
}
- (void)removeInfloderObject:(FloderEntity *)value
{
    NSMutableSet *inFloder = [self.infloder mutableCopy];
    [inFloder removeObject:value];
    self.infloder = inFloder;
}

- (void)addInfloder:(NSSet<FloderEntity *> *)values
{
    NSMutableSet *inFloder = [self.infloder mutableCopy];
    for (FloderEntity *floderEntity in values) {
        [inFloder addObject:floderEntity];
    }
    self.infloder = inFloder;
}

- (void)removeInfloder:(NSSet<FloderEntity *> *)values
{
    NSMutableSet *inFloder = [self.infloder mutableCopy];
    for (FloderEntity *floderEntity in values) {
        [inFloder removeObject:floderEntity];
    }
    self.infloder = inFloder;
}
@end

然后测试代码如下

#import "AppDelegate.h"
#import <CoreData/CoreData.h>
#import "FloderEntity+CoreDataClass.h"
#import "FloderEntity+CoreDataProperties.h"
#import "FileEntity+CoreDataClass.h"
#import "FileEntity+CoreDataProperties.h"

@interface AppDelegate ()

@property (nonatomic,readwrite,strong)NSManagedObjectModel *managedObjectModel;
@property (nonatomic,readwrite,strong)NSPersistentStoreCoordinator *persistentStoreCoordinator;
@property (nonatomic,readwrite,strong)NSManagedObjectContext *context;

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [self managedObjectModel];
    [self persistentStoreCoordinator];
    [self context];
//    [self loadFiles];
    [self fetchEntity];
    
    return YES;
}

- (NSManagedObjectModel *)managedObjectModel
{
    if (!_managedObjectModel)
    {
        NSURL *modelURL = [[NSBundle mainBundle]URLForResource:@"CSCoreDataDemo02" withExtension:@"momd"];
        _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    }
    return _managedObjectModel;
}

- (NSPersistentStoreCoordinator*)persistentStoreCoordinator
{
    if (!_persistentStoreCoordinator) {
        _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]initWithManagedObjectModel:self.managedObjectModel];
        NSURL *sqlURL = [[self documentDirectoryURL] URLByAppendingPathComponent:@"CSCoreDataDemo.sqlite"];
        NSError *error;
        [_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:sqlURL options:nil error:&error];
        
        if (error) {
            NSLog(@"falied to create persistentStoreCoordinator %@",error.localizedDescription);
        }
    }
    return _persistentStoreCoordinator;
}

-  (NSManagedObjectContext*)context
{
    if (!_context) {
        _context = [[NSManagedObjectContext alloc]initWithConcurrencyType:NSMainQueueConcurrencyType];
        _context.persistentStoreCoordinator = self.persistentStoreCoordinator;
    }
    return _context;
}

- (NSError*)saveContext
{
    NSError *error = nil;
    if ([self.context hasChanges])
        [self.context save:&error];//使操作生效
    
    if (error) return error;
    else return nil;
}

- (NSURL*)documentDirectoryURL
{
    return [[NSFileManager defaultManager]URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask].lastObject;
}
- (void)loadFiles
{
    NSMutableArray *fileArray = [[NSMutableArray alloc]init];

    for (int i = 0; i < 50; i++) {
        FileEntity *fileEntity = [NSEntityDescription insertNewObjectForEntityForName:@"FileEntity" inManagedObjectContext:self.context];
        fileEntity.id = 10000 + i;
        fileEntity.name = [NSString stringWithFormat:@"OFD_%d",10000 + i];
        [fileArray addObject:fileEntity];
    }

    for (int i = 0; i < 10; i++) {
        FloderEntity *floderEntity = [NSEntityDescription insertNewObjectForEntityForName:@"FloderEntity" inManagedObjectContext:self.context];
        floderEntity.id = 1000 + i;
        floderEntity.name = [NSString stringWithFormat:@"floder_%d",1000 + i];
        NSMutableSet *files = [[NSMutableSet alloc]init];
        for (int j = 0; j<5; j++) {
            [files addObject:[fileArray objectAtIndex:(i*5 + j)]];
        }
        [floderEntity addFiles:files];
    }
    
    
    [self saveContext];
}

- (void)fetchEntity
{
    NSFetchRequest *floderRequest = [NSFetchRequest fetchRequestWithEntityName:@"FloderEntity"];
    NSSortDescriptor *floderSort = [[NSSortDescriptor alloc]initWithKey:@"id" ascending:YES];
    [floderRequest setSortDescriptors:[NSArray arrayWithObjects:floderSort,nil]];
    NSArray *floders = [_context executeFetchRequest:floderRequest error:nil];
    for (int i = 0; i<floders.count; i++) {
        FloderEntity *floderEntity = [floders objectAtIndex:i];
        NSSet *files = floderEntity.files;
        for (FileEntity *file in files) {
            NSLog(@"file %d   %@\r\n",file.id,file.name);
        }
    }
    
    NSFetchRequest *fileRequest = [NSFetchRequest fetchRequestWithEntityName:@"FileEntity"];
    NSArray *files = [_context executeFetchRequest:fileRequest error:nil];
    

    for (int i = 0; i<files.count; i++) {
        FileEntity *fileEntity = [files objectAtIndex:i];
        
        NSSet * floders = fileEntity.infloder;
        
        for (FloderEntity *floder in floders) {
            NSLog(@"floder %d  %@\r\n",floder.id,floder.name);
        }
    }
}
@end