CoreData的简单使用<三、CoreData分页查询和模糊查询>

////  ViewController.m//  CoreData////  Created by YanFengZheng on 16/8/27.//  Copyright © 2016年 fe. All rights reserved.//#import "ViewController.h"#import <CoreData/CoreData.h>#import "Employee.h"@interface ViewController ()@property (nonatomic,strong) NSManagedObjectContext *context;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    //1.创建模型文件［相当于数据库里的表］    //2.添加实体   ［一张表］    //3.创建实体类 ［相当于模型］    //4.生成上下文 关联模型文件生成数据库    //4.1上下文    NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];    //4.2持久化存储协调器    NSManagedObjectModel *model = [NSManagedObjectModel mergedModelFromBundles:nil];    NSPersistentStoreCoordinator *store = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];    //4.3设置数据库路径    NSString *doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];    NSString *sqlitePath = [doc stringByAppendingPathComponent:@"company.sqlite"];    NSLog(@"%@",sqlitePath);    [store addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:[NSURL fileURLWithPath:sqlitePath] options:nil error:nil];    context.persistentStoreCoordinator = store;    self.context = context;        /*在写以上代码的时候，先初始化上下文，再初始化上下文需要的持久化存储协调器，再初始化持久化存储协调器所需要的模型文件，最后添加持久化类型和文件路径。个人感觉按照这个方法比较容易记忆。     */}#pragma mark - 数据库操作 增、删、改、查//1.插入数据- (IBAction)insertData:(UIButton *)sender {    //插入数据的时候，需要使用实体描述拿到实体模型    for (int i = 0; i<15; i++) {        Employee *employee = [NSEntityDescription insertNewObjectForEntityForName:@"Employee" inManagedObjectContext:self.context];        employee.name = [NSString stringWithFormat:@"wangwu%u",(unsigned)i];        employee.height = @(1.78+i);        employee.birthday = [NSDate date];    }        [self.context  save:nil];}- (IBAction)deleteData:(UIButton *)sender {    //1:先查询到需要删除的数据(比如这里以删除员工张三的数据为例)    //1.1:FectchRequest 抓取请求对象    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];    //1.2:设置过滤条件    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name = %@",@"张三"];    request.predicate = pre;    //1.3执行查询请求    NSArray *emps = [self.context executeFetchRequest:request error:nil];    //2:执行删除操作    for (Employee *emp in emps) {        [self.context deleteObject:emp];    }        //3:保存    [self.context save:nil];}//更新数据- (IBAction)upDateData:(UIButton *)sender {    //1:先查询出需要更新的数据    //1.1:FectchRequest 抓取请求对象    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];    //1.2:设置过滤条件    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name = %@",@"张三"];    request.predicate = pre;    //1.3执行查询请求    NSArray *emps = [self.context executeFetchRequest:request error:nil];    //2:更新数据    for (Employee *emp  in emps) {        emp.height = @3;    }    //3:保存    [self.context save:nil];}//查询员工- (IBAction)queryData:(UIButton *)sender {    //1:分页查询    //[self limitFetch];        //2:模糊查询    [self fuzzyFetch];        }- (void)limitFetch{    //1:FectchRequest 抓取请求对象    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];        //2:设置分页查询    request.fetchOffset = 6;//设置查询开始位置    request.fetchLimit = 6;//设置每一次(页)查询数据的条数    //3:设置排序    NSSortDescriptor *height = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:YES];    request.sortDescriptors = @[height];        //4:执行请求    NSArray *emps = [self.context executeFetchRequest:request error:nil];    //遍历查询结果    for (Employee *emp in emps) {        NSLog(@"名字：%@,身高：%@,生日：%@",emp.name,emp.height,emp.birthday);    }    }- (void)fuzzyFetch{    //1:FectchRequest 抓取请求对象    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Employee"];        //2:设置模糊查询条件(谓词)    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name BEGINSWITH %@",@"wangwu1"];//查询姓名以wangwu1开头的员工    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name ENDSWITH %@",@"1"];//查询姓名以1结尾的员工    //NSPredicate *pre = [NSPredicate predicateWithFormat:@"name CONTAINS %@",@"wu13"];//查询姓名中包含wu13的员工    NSPredicate *pre = [NSPredicate predicateWithFormat:@"name like %@",@"*wu13"];//查询姓名以wu13结尾的员工，＊wu13中的＊是通配符，如果写成wu13*则表示名字以wu13开头的员工        request.predicate = pre;        //3:设置排序    NSSortDescriptor *height = [NSSortDescriptor sortDescriptorWithKey:@"height" ascending:YES];    request.sortDescriptors = @[height];        //4:执行请求    NSArray *emps = [self.context executeFetchRequest:request error:nil];    //遍历查询结果    for (Employee *emp in emps) {        NSLog(@"名字：%@,身高：%@,生日：%@",emp.name,emp.height,emp.birthday);    }}@end