LKDBHelper和MagicalRecord的基本用法

LKDBHelper是对FMDB的封装，可以在不写sql语句的情况下，使用model就可以全自动的进行数据表的创建，及数据的增、删、改、查。

MagicalRecord是对CoreData的简单封装

引入方式cocoachina：

pod 'MagicalRecord', '~> 2.3.2'
pod 'LKDBHelper', '~> 2.5.1'

---

LKDBHelper初始化

LKDBModel是我需要存储的类，.h文件：

@property (nonatomic , assign) NSInteger model_id;

@property (nonatomic , strong) NSString *name;

@property (nonatomic , assign) BOOL isShow;

@property (nonatomic , strong) NSArray *dataArray;

//由于发现字典类型不能直接存储，所以转成NSString进行存储。
@property (nonatomic , strong) NSString *dataDictString;

.m文件，首先引入#import "LKDBHelper.h"头文件，一般情况，设置一个主键名就行：

///**设置表名，一般不写，默认表名为类名*/
//+(NSString *)getTableName
//{
//    return @"LKDB.db";
//}

/**主键名*/
+(NSString *)getPrimaryKey
{
    return @"model_id";
}

/**复合主键*/
//+(NSArray *)getPrimaryKeyUnionArray
//{
//
//}

---

LKDBHelper增

    LKDBModel *model=[[LKDBModel alloc]init];
    model.model_id=self.count;
    model.name=[NSString stringWithFormat:@"name-%ld",self.count];
    if (self.count%2==0) {
        model.isShow=YES;
    }
    else{
        model.isShow=NO;
    }
    
    NSMutableArray *array=[[NSMutableArray alloc]init];
    for (NSInteger i=0; i

---

LKDBHelper删

方式一（直接删除某个model）：

BOOL success=[self.helper deleteToDB:model];

方式二（根据条件删除）：

BOOL success=[self.helper deleteWithClass:[LKDBModel class] where:@{@"model_id":[NSNumber numberWithInteger:model.model_id]}];

---

LKDBHelper改

model.name=[NSString stringWithFormat:@"changeName-%ld",self.count];
BOOL success=[model saveToDB];

---

LKDBHelper查

[self.helper search:[LKDBModel class] where:nil orderBy:nil offset:0 count:0 callback:^(NSMutableArray * _Nullable array) {
    NSLog(@"searchButtonClick:%@",array);
}];

---

coreData的使用

新建一个coreData

---

MagicalRecord初始化，一般在AppDelegate.m的didFinishLaunchingWithOptions函数进行初始化

    [MagicalRecord setupCoreDataStack];
    [MagicalRecord setupCoreDataStackWithStoreNamed:@"MagicalRecord.sqlite"];

    self.localContext    = [NSManagedObjectContext MR_context];

---

MagicalRecord增

//初始化一个Model
    MRModel *model=[MRModel MR_createEntityInContext:self.localContext];
//对该Model进行赋值
    model.id=self.count;
    model.name=[NSString stringWithFormat:@"name-%ld",self.count];
    if (self.count%2==0) {
        model.isShow=YES;
    }
    else{
        model.isShow=NO;
    }

//这句话很重要。增删改查都要用这个方法来保存数据
[self.localContext MR_saveToPersistentStoreAndWait];

---

MagicalRecord删

• 先查再删 删除所有符合条件的数据

    NSPredicate *predicate=[NSPredicate predicateWithFormat:@"id=3"];
    NSFetchRequest *request=[[NSFetchRequest alloc]init];
    [request setPredicate:predicate];
    NSEntityDescription *entity=[NSEntityDescription entityForName:@"MRModel" inManagedObjectContext:self.localContext];
    [request setEntity:entity];
    NSArray *arr=[self.localContext executeFetchRequest:request error:nil];
    [arr enumerateObjectsUsingBlock:^(MRModel * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        BOOL success=[obj MR_deleteEntity];
        if (success) {
            NSLog(@"删除成功");
        }
        else{
            NSLog(@"删除失败");
        }
    }];
    //必须要加上这句话，不然没法删除成功
    [self.localContext MR_saveToPersistentStoreAndWait];

• 直接删 删除第一条符合条件的数据

    NSPredicate *predicate=[NSPredicate predicateWithFormat:@"id=1"];
    BOOL success = [MRModel MR_deleteAllMatchingPredicate:predicate inContext:self.localContext];
    if (success) {
        NSLog(@"删除成功");
    }
    else{
        NSLog(@"删除失败");
    }
    [self.localContext MR_saveToPersistentStoreAndWait];

---

MagicalRecord改

• 用MR_findByAttribute查找并修改

NSArray *array=[MRModel MR_findByAttribute:@"id" withValue:[NSNumber numberWithInteger:1]];
    [array enumerateObjectsUsingBlock:^(MRModel * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        obj.name=@"修改-name";
    }];
    [self.localContext MR_saveToPersistentStoreAndWait];

• 用NSFetchRequest查找并修改

    NSFetchRequest *request=[[NSFetchRequest alloc]init];
    [request setPredicate:predicate];
    NSEntityDescription *entity=[NSEntityDescription entityForName:@"MRModel" inManagedObjectContext:self.localContext];
    [request setEntity:entity];
    NSArray *arr=[self.localContext executeFetchRequest:request error:nil];
    [arr enumerateObjectsUsingBlock:^(MRModel * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"id: %lld , \nname: %@ ,\nisShow：%d", obj.id, obj.name,obj.isShow);
        obj.name=@"修改-name";
    }];
    [self.localContext MR_saveToPersistentStoreAndWait];

---

MagicalRecord查

• 查找所有

    NSArray *array=[MRModel MR_findAll];
    [array enumerateObjectsUsingBlock:^(MRModel * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"id: %lld , \nname: %@ ,\nisShow：%d", obj.id, obj.name,obj.isShow);
    }];

• 根据条件查找

    NSPredicate *predicate=[NSPredicate predicateWithFormat:@"isShow=1"];
    NSFetchRequest *request=[[NSFetchRequest alloc]init];
    [request setPredicate:predicate];
    NSEntityDescription *entity=[NSEntityDescription entityForName:@"MRModel" inManagedObjectContext:self.localContext];
    [request setEntity:entity];
    NSArray *arr=[self.localContext executeFetchRequest:request error:nil];
    [arr enumerateObjectsUsingBlock:^(MRModel * obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"id: %lld , \nname: %@ ,\nisShow：%d", obj.id, obj.name,obj.isShow);
    }];

源码：github