ios coreData sqlite3

//
//  ViewController.m
//  CoreDataByStoryboard
//
//  Created by 何瑾 on 15/1/15.
//  Copyright (c) 2015年 e世雕龙. All rights reserved.
//

#import "ViewController.h"
#import "Student.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UITextField *txtName;// 姓名文本框
@property (weak, nonatomic) IBOutlet UITextField *txtAge;// 年龄文本框
@property (weak, nonatomic) IBOutlet UITextField *txtID;// ID文本框
@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;// 托管对象上下文（类似于sqlite3编程中数据库的缓冲区）
@property (strong, nonatomic) NSArray *students;// 查询出来的学生数组
@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
[self getDocPath];
// Do any additional setup after loading the view, typically from a nib.
// 1、获取应用程序对象
UIApplication *app = [UIApplication sharedApplication];
// 2、获取应用程序的委托
id appDelegate = app.delegate;
// 3、获取应用程序中的托管对象上下文
self.managedObjectContext = [appDelegate managedObjectContext];
}
#pragma mark 注册
- (IBAction)btnRegister:(id)sender {
// 通过实体描述类创建数据模型（托管对象）放入托管对象上下文中
Student *stu = [NSEntityDescription insertNewObjectForEntityForName:@"Student" inManagedObjectContext:self.managedObjectContext];
// 给数据模型（托管对象）属性绑定界面数据
static int i = 0;
i++;
stu.id = [NSNumber numberWithInt:i];
stu.name = self.txtName.text;
stu.age = [NSNumber numberWithInt:[self.txtAge.text intValue]];
stu.address = @"北京人";
// 通过托管对象上下文保存数据模型（托管对象）
__autoreleasing NSError *error = nil;
[self.managedObjectContext save:&error];
// 判断是否保存成功
if (error) {
[self myAlert:@"托管对象保存失败！"];
} else {
[self myAlert:@"托管对象保存成功！"];
}
}
#pragma mark 查询
- (IBAction)btnSearch:(id)sender {
// 1、创建抓取请求对象
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Student"];
// 从界面获取查询条件
NSNumber *id = [NSNumber numberWithInt:[self.txtID.text intValue]];
NSLog(@"id:%@",id);
// 2、创建谓词（查询条件）
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"id=%@",id];
// 2.1把谓词放入抓取请求对象中
[request setPredicate:predicate];
// 3、创建排序规则
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"id" ascending:YES];
// 3.1把排序规则放入抓取请求对象中
[request setSortDescriptors:@[sortDescriptor]];
// 4、执行抓取（查询）
__autoreleasing NSError *error = nil;
self.students = [self.managedObjectContext executeFetchRequest:request error:&error];
if (error) {
[self myAlert:@"查询失败！"];
} else {
[self myAlert:@"查询成功！请看控制台！"];
NSLog(@"students:%@",self.students);
}
}
#pragma mark 封装UIAlertView
- (void)myAlert:(NSString *)errorMsg {
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"信息" message:errorMsg delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];
[alert show];
}
#pragma mark 获取应用沙盒的documents目录路径
- (NSString *)getDocPath {
NSArray *docPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docPath = docPaths[0];
NSLog(@"docPath:%@",docPath);
return docPath;
}
@end