【iOS】数据库Core Data的使用

在前面的博客《【iOS】数据库FMDB的使用》介绍了FMDB的使用，但是FMDB不是数据库。接下来需要介绍的core Data也不是数据库。

一、core Data是什么？

https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CoreData/index.html#//apple_ref/doc/uid/TP40001075

Core Data is a framework that you use to manage the model layer objects in your application. It provides generalized and automated solutions to common tasks associated with object life cycle and object graph management, including persistence.

这个是苹果给出来的。大意：

core Data是一个用于管理模型层对象在应用程序中使用的架构。它提供了通用的和自动化的解决方案，与对象的生命周期和对象图管理。包括持久的共同任务。

core Data不是数据库，是一个架构，对象关系映射(ORM,Object-Relational Mapping)。

二、core Data的使用

具体操作可以参考着两篇博客。介绍的很详细。

http://blog.csdn.net/q199109106q/article/details/8563438/

http://my.oschina.net/pljhonglu/blog/199193

#import "ViewController.h"#import <CoreData/CoreData.h>#import "Person+CoreDataProperties.h"#import "Person.h"@interface ViewController ()@property (nonatomic,strong)NSManagedObjectContext *context;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        [self createCoreDataModel];    // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (void)createCoreDataModel{    // 1.取文件路径    NSString * corDataPath = [[NSBundle mainBundle] pathForResource:@"Person" ofType:@"momd"];    // 2.取出CoreData在工程中的模型    NSManagedObjectModel * model = [[NSManagedObjectModel alloc] initWithContentsOfURL:[NSURL URLWithString:corDataPath]];    // 3.制作一个关联层 CoreData和sqlite关联    NSPersistentStoreCoordinator *coor = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];    // 4.创建一个数据库地址    NSString * dbPath = [NSString stringWithFormat:@"%@/Documents/data.sqlite",NSHomeDirectory()];    NSLog(@"dbPath = %@",dbPath);    // 5.关联层创建数据库返回的对象  创建失败store = nil    NSPersistentStore * store = [coor addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[NSURL fileURLWithPath:dbPath] options:0 error:nil];    NSLog(@"store = %@",store);    //制作一个操作对象    self.context = [[NSManagedObjectContext alloc] init];    self.context.persistentStoreCoordinator = coor;}/** *  插入数据 */- (void)insterData{    Person * p1 = [NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:self.context];    p1.name = [NSString stringWithFormat:@"张三%u",arc4random()%30];    p1.age = [NSString stringWithFormat:@"%u",arc4random()%30];    p1.height = [NSString stringWithFormat:@"1.%u",arc4random()%100];    p1.sex = @"男";    BOOL isInsret = [self.context save:nil];  //ret = 1插入成功    NSLog(@"isInsret = %d",isInsret);}/** *  删除数据 */- (void)deleteData{ //包含查询操作    //创建一个查询  返回结果的对象    NSFetchRequest * request = [[NSFetchRequest alloc] initWithEntityName:@"Person"];    //获取sqlite里面的所有对象 相当于是查询    NSArray * dataArr = [self.context executeFetchRequest:request error:nil];    [self.context deleteObject:dataArr[0]]; //删除一条数据  全部删除就遍历数组dataArr 逐条删除    BOOL isDelete = [self.context save:nil];  //回写    NSLog(@"isDelete = %d",isDelete);}/** *  修改和查询 */- (void)modifyData{    //创建一个查询  返回结果的对象    NSFetchRequest * request = [[NSFetchRequest alloc] initWithEntityName:@"Person"];    NSArray * dataArr = [self.context executeFetchRequest:request error:nil]; //  获取数据库里面的全部数据模型    Person * p1 = (Person *)dataArr[0];    p1.name = @"CFire";    BOOL isModify = [self.context save:nil]; // 修改第0个模型的姓名    NSLog(@"isModify = %d",isModify);    NSPredicate * predicate = [NSPredicate predicateWithFormat:@"name like %@",@"小明"];//查询全部名字叫小明的人    [request setPredicate:predicate];    NSArray * arr1 = [self.context executeFetchRequest:request error:nil];    for (Person * p in arr1) {        NSLog(@"name = %@",p.name);    }}- (IBAction)insterData:(id)sender {    [self insterData];}- (IBAction)deldte:(UIButton *)sender {    [self deleteData];}- (IBAction)select:(UIButton *)sender {    [self modifyData];}@end

打开沙盒里面的数据库文件

可以看见操作成功了。

代码下载地址---请点击我。