基于iOS Realm数据库的使用实例详解

首先下载realm源代码，

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

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

以上这篇基于ios realm数据库的使用实例详解就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。