IOS数据存储之CoreData使用优缺点

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>@interface CoreDataManager : NSObject<NSCopying>@property(strong,nonatomic,readonly)NSManagedObjectModel* managedObjectModel;//管理数据模型@property(strong,nonatomic,readonly)NSManagedObjectContext* managedObjectContext;//管理数据内容@property(strong,nonatomic,readonly)NSPersistentStoreCoordinator* persistentStoreCoordinator;//持久化数据助理//创建数据库管理者单例
+(instancetype)shareManager;//插入数据
-(void)insertData:(NSString*)tempName;//删除数据
-(void)deleteData;//删除数据
-(void)deleteData:(NSString*)tempName;//查询数据
-(void)queryData;//根据条件查询
-(void)queryData:(NSString*)tempName;//更新数据
-(void)updateData:(NSString*)tempName;@end

#import "CoreDataManager.h"
#import "Car.h"static CoreDataManager *shareManager=nil;@implementation CoreDataManager@synthesize managedObjectContext =_managedObjectContext;@synthesize managedObjectModel = _managedObjectModel;@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;//实例化对象
-(instancetype)init
{
self=[super init];
if (self) { }
return self;
}//创建数据库管理者单例
+(instancetype)shareManager
{
//这里用到了双重锁定检查
if(shareManager==nil){
@synchronized(self){
if(shareManager==nil){
shareManager =[[[self class]alloc]init];
}
}
}
return shareManager;
}-(id)copyWithZone:(NSZone *)zone
{ return shareManager;
}+(id)allocWithZone:(struct _NSZone *)zone
{
if(shareManager==nil){
shareManager =[super allocWithZone:zone];
}
return shareManager;
}//托管对象
-(NSManagedObjectModel *)managedObjectModel
{
if (_managedObjectModel!=nil) {
return _managedObjectModel;
} NSURL* modelURL=[[NSBundle mainBundle] URLForResource:@"myCoreData" withExtension:@"momd"];
_managedObjectModel=[[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;
}//托管对象上下文
-(NSManagedObjectContext *)managedObjectContext
{
if (_managedObjectContext!=nil) {
return _managedObjectContext;
} NSPersistentStoreCoordinator* coordinator=[self persistentStoreCoordinator];
if (coordinator!=nil) {
_managedObjectContext=[[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];//NSMainQueueConcurrencyType NSPrivateQueueConcurrencyType [_managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return _managedObjectContext;
}//持久化存储协调器
-(NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (_persistentStoreCoordinator!=nil) {
return _persistentStoreCoordinator;
}
NSString* docs=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];
NSURL* storeURL=[NSURL fileURLWithPath:[docs stringByAppendingPathComponent:@"myCoreData.sqlite"]];
NSLog(@"path is %@",storeURL);
NSError* error=nil;
_persistentStoreCoordinator=[[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(@"Error: %@,%@",error,[error userInfo]);
}
return _persistentStoreCoordinator;
}//插入数据
-(void)insertData:(NSString*)tempName
{
//读取类
Car *car=[NSEntityDescription insertNewObjectForEntityForName:@"Car" inManagedObjectContext:self.managedObjectContext];
car.name=tempName;
//保存
NSError *error;
[self.managedObjectContext save:&error];
}//删除数据
-(void)deleteData
{
//创建读取类
NSEntityDescription *entity =[NSEntityDescription entityForName:@"Car" inManagedObjectContext:self.managedObjectContext]; //创建连接
NSFetchRequest* request=[[NSFetchRequest alloc] init];
[request setEntity:entity]; //启动查询
NSError *error;
NSArray *deleteArr=[self.managedObjectContext executeFetchRequest:request error:&error];
if(deleteArr.count){
for (Car *car in deleteArr) {
[self.managedObjectContext deleteObject:car];
}
NSError *error;
[self.managedObjectContext save:&error];
}else{
NSLog(@"未查询到可以删除的数据");
}}//删除数据
-(void)deleteData:(NSString*)tempName;
{
//创建读取类
NSEntityDescription *entity =[NSEntityDescription entityForName:@"Car" inManagedObjectContext:self.managedObjectContext]; //创建连接
NSFetchRequest* request=[[NSFetchRequest alloc] init];
[request setEntity:entity]; //创建检索条件
NSPredicate *predicate =[NSPredicate predicateWithFormat:@"name=%@",tempName];
[request setPredicate:predicate]; //启动查询
NSError *error;
NSArray *deleteArr=[self.managedObjectContext executeFetchRequest:request error:&error];
if(deleteArr.count){
for (Car *car in deleteArr) {
[self.managedObjectContext deleteObject:car];
}
NSError *error;
[self.managedObjectContext save:&error];
}else{
NSLog(@"未查询到可以删除的数据");
}
}//查询数据
-(void)queryData
{
//创建读取类
NSEntityDescription *entity =[NSEntityDescription entityForName:@"Car" inManagedObjectContext:self.managedObjectContext]; //创建连接
NSFetchRequest* request=[[NSFetchRequest alloc] init];
[request setEntity:entity]; //启动查询
NSError *error;
NSArray *carArr=[self.managedObjectContext executeFetchRequest:request error:&error];
for(Car *car in carArr){
NSLog(@"car---->%@",car.name);
}}-(void)queryData:(NSString*)tempName
{
//创建读取类
NSEntityDescription *entity =[NSEntityDescription entityForName:@"Car" inManagedObjectContext:self.managedObjectContext]; //创建连接
NSFetchRequest* request=[[NSFetchRequest alloc] init];
[request setEntity:entity]; //创建检索条件
NSPredicate *predicate =[NSPredicate predicateWithFormat:@"name=%@",tempName];
[request setPredicate:predicate]; //启动查询
NSError *error;
NSArray *carArr=[self.managedObjectContext executeFetchRequest:request error:&error];
for(Car *car in carArr){
NSLog(@"car---->%@",car.name);
}}//更新数据
-(void)updateData:(NSString*)tempName
{
//创建读取类
NSEntityDescription *entity =[NSEntityDescription entityForName:@"Car" inManagedObjectContext:self.managedObjectContext]; //创建连接
NSFetchRequest* request=[[NSFetchRequest alloc] init];
[request setEntity:entity]; //创建检索条件
NSPredicate *predicate =[NSPredicate predicateWithFormat:@"name=%@",tempName];
[request setPredicate:predicate]; //启动查询
NSError *error;
NSArray *deleteArr=[self.managedObjectContext executeFetchRequest:request error:&error];
if(deleteArr.count){
for (Car *car in deleteArr) {
car.name=@"test";
}
NSError *error;
[self.managedObjectContext save:&error];
}else{
NSLog(@"未查询到可以删除的数据");
}}@end