iOS Realm数据库的使用

首先下载Realm源代码，https://realm.io/cn/docs/objc/latest

将下载的文件解压，从 ios/static/ 目录中将 Realm.framework 拖曳到 Xcode 工程的文件导航器内，然后在 Xcode 文件导航器中选中工程。然后选择应用目标，前往 Build Phases 选项卡。在 Link Binary with Libraries 部分中单击 + 按钮，然后添加 libc++.tbd 和 libz.tbd。这样还没有完，我们还需要安装插件，打开解压文件夹下的plugin，运行RealmPlugin.xcodeproj，然后重启XCode。

这样环境配置就完了，现在说重点如何去使用。

1.创建实体类
new File翻到最下面点击创建Realm实体类

#import <Realm/Realm.h> @interface TestBean : RLMObject @property NSString* name; @property NSInteger age; @end // This protocol enables typed collections. i.e.: // RLMArray<TestBean *><TestBean> RLM_ARRAY_TYPE(TestBean) #import "TestBean.h" @implementation TestBean @end 

2.增删改查

这个增加，可以看到直接添加实体类就行了，这个RLMRealm就是数据库的操作类，以后所有操作都靠他。

-(void)addAction{
  NSLog(@"add"); self.name = _tf_name.text; self.age = [_tf_age.text integerValue]; TestBean* bean = [[TestBean alloc]init]; bean.name = self.name; bean.age = self.age; RLMRealm *realm = [RLMRealm defaultRealm]; [realm transactionWithBlock:^{
    [realm addObject:bean]; }]; }

删除也是通过删除实体类来实现，但是我们需要首先通过查询出实体类才行。这个查询我们可以看到通过我们创建的实体类就能实现

-(void)deleteAction{ NSLog(@"delete"); RLMResults *dogs = [TestBean allObjects]; RLMRealm *realm = [RLMRealm defaultRealm]; [realm transactionWithBlock:^{ for (TestBean *bean in dogs) { [realm deleteObject:bean]; } }]; } 

更新也是通过改变实体类的数据来实现

-(void)updateAction{ NSLog(@"update"); RLMResults *dogs = [TestBean allObjects]; [[RLMRealm defaultRealm] transactionWithBlock:^{ for (TestBean *bean in dogs) { bean.name = @"李四";
    }
  }];
}

查询我们还可以添加条件

// 使用断言字符串来查询 RLMResults<Dog *> *tanDogs = [Dog objectsWhere:@"color = 'tan' AND name BEGINSWITH 'B'"]; // 使用 NSPredicate 来查询 NSPredicate *pred = [NSPredicate predicateWithFormat:@"color = %@ AND name BEGINSWITH %@", @"tan", @"B"];
tanDogs = [Dog objectsWithPredicate:pred];

3.排序

这个是在查询完后去实现，通过实体类的key来排序。

-(void)sortAction{ NSLog(@"query");

  RLMResults *dogs = [[TestBean allObjects] sortedResultsUsingKeyPath:@"name" ascending:YES];
  [[RLMRealm defaultRealm] transactionWithBlock:^{ for (TestBean *bean in dogs) { NSLog(@"%@",bean.name);
    }

  }];


}

4.小结

只说了常用的功能，贴上官方中文文档供大家参考
https://realm.io/cn/docs/objc/latest

5.例子代码

// // ViewController.m // BmobTest // // Created by shanreal-iOS on 2017/12/9. // Copyright © 2017年 shanreal.LongZhenHao. All rights reserved. // #import "ViewController.h" #import "TestBean.h" @interface ViewController () @property(nonatomic,strong)UIButton* add; @property(nonatomic,strong)UIButton* delete; @property(nonatomic,strong)UIButton* update; @property(nonatomic,strong)UIButton* query; @property(nonatomic,strong)UIButton* sort; @property(nonatomic,strong)NSString* name; @property(nonatomic,assign)NSInteger* age; @property(nonatomic,strong)UITextField* tf_name; @property(nonatomic,strong)UITextField* tf_age; @end @implementation ViewController - (void)viewDidLoad {
  [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. _add = [[UIButton alloc]initWithFrame:CGRectMake(10, 30, 100, 20)];
  [_add setTitle:@"add" forState:UIControlStateNormal];
  [_add setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
  [_add addTarget:self action:@selector(addAction) forControlEvents:UIControlEventTouchUpInside];

  _delete = [[UIButton alloc]initWithFrame:CGRectMake(10, 60, 100, 20)];
  [_delete setTitle:@"delete" forState:UIControlStateNormal];
  [_delete setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
  [_delete addTarget:self action:@selector(deleteAction) forControlEvents:UIControlEventTouchUpInside];

  _update = [[UIButton alloc]initWithFrame:CGRectMake(10, 90, 100, 20)];
  [_update setTitle:@"update" forState:UIControlStateNormal];
  [_update setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
  [_update addTarget:self action:@selector(updateAction) forControlEvents:UIControlEventTouchUpInside];



  _query = [[UIButton alloc]initWithFrame:CGRectMake(10, 120, 100, 20)];
  [_query setTitle:@"query" forState:UIControlStateNormal];
  [_query setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
  [_query addTarget:self action:@selector(queryAction) forControlEvents:UIControlEventTouchUpInside];

  _sort = [[UIButton alloc]initWithFrame:CGRectMake(10, 150, 100, 20)];
  [_sort setTitle:@"sort" forState:UIControlStateNormal];
  [_sort setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
  [_sort addTarget:self action:@selector(sortAction) forControlEvents:UIControlEventTouchUpInside];


  _tf_name = [[UITextField alloc]initWithFrame:CGRectMake(50, 300, 200, 20)];
  _tf_name.placeholder=@"name";

  _tf_age = [[UITextField alloc]initWithFrame:CGRectMake(50, 350, 200, 20)];
  _tf_age.placeholder=@"age";

  [self.view addSubview:_add];
  [self.view addSubview:_delete];
  [self.view addSubview:_update];
  [self.view addSubview:_query];
  [self.view addSubview:_sort];
  [self.view addSubview:_tf_name];
  [self.view addSubview:_tf_age];
}

-(void)addAction{ NSLog(@"add"); self.name = _tf_name.text; self.age = [_tf_age.text integerValue];


  TestBean* bean = [[TestBean alloc]init];
  bean.name = self.name;
  bean.age = self.age;

  RLMRealm *realm = [RLMRealm defaultRealm];
  [realm transactionWithBlock:^{
    [realm addObject:bean];
  }];


}

-(void)deleteAction{ NSLog(@"delete");
  RLMResults *dogs = [TestBean allObjects];
  RLMRealm *realm = [RLMRealm defaultRealm];

  [realm transactionWithBlock:^{ for (TestBean *bean in dogs) {
      [realm deleteObject:bean];
    }

  }];

}

-(void)updateAction{ NSLog(@"update");
  RLMResults *dogs = [TestBean allObjects];
  [[RLMRealm defaultRealm] transactionWithBlock:^{ for (TestBean *bean in dogs) {
      bean.name = @"李四";
    }
  }];
}

-(void)queryAction{ NSLog(@"query");

  RLMResults *dogs = [TestBean allObjects];
  [[RLMRealm defaultRealm] transactionWithBlock:^{ for (TestBean *bean in dogs) { NSLog(@"%@",bean.name);
    }

  }];


}

-(void)sortAction{ NSLog(@"query");

  RLMResults *dogs = [[TestBean allObjects] sortedResultsUsingKeyPath:@"name" ascending:YES];
  [[RLMRealm defaultRealm] transactionWithBlock:^{ for (TestBean *bean in dogs) { NSLog(@"%@",bean.name);
    }

  }];


}

- (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end