IOS之数据库的查找，删除，添加，更新

DB类之.h文件
#import <Foundation/Foundation.h>
#import <sqlite3.h>

@inte易做图ce DB : NSObject
+(sqlite3 *)openDB;//打开数据库
-(void)closeDB;//关闭数据库

@end

DB类之.m文件
#import "DB.h"
#import <sqlite3.h>
static sqlite3 *db = nil;
@implementation DB
+(sqlite3 *)openDB
{
    if(db)
    {
        return db;
    }
    //目标路径
    NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDirectory, YES)objectAtIndex:0];
    //原始路径
    NSString *filePath = [docPath stringByAppendingPathComponent:@"db.sqlite"];

    NSFileManager *fm = [NSFileManager defaultManager];

    if ([fm fileExistsAtPath:filePath] == NO)//如果doc下没有数据库，从bundle里面拷贝过来

    {
        NSString *bundle = [[NSBundle mainBundle]pathForResource:@"classDB" ofType:@"sqlite"];

        NSError *err = nil;

        if ([fm copyItemAtPath:bundle toPath:filePath error:&err] == NO) //如果拷贝失败
        {
            NSLog(@"%@",[err localizedDescription]);
        }


    }
    sqlite3_open([filePath UTF8String], &db);
    return db;
}
-(void)closeDB
{
    if (db)
    {
        sqlite3_close(db);
    }

}
@end
Person类.h文件
#import <Foundation/Foundation.h>

@inte易做图ce Person : NSObject
@property(nonatomic,retain)NSString *name,*phone;
@property(nonatomic,assign)int age,ID;

-(id)initWithName:(NSString *)name phone:(NSString *)phone age:(int)age ID:(int)ID;

+(NSMutableArray *)findAll;
+(int)count;
+(Person *)findByID:(int)ID;
+(NSMutableArray *)findByname:(NSString *)name;
+(void)addName:(NSString *)name phone:(NSString *)phone age:(int)age;
+(void)deleteByID:(int)ID;
+(void)updataName:(NSString *)name phone:(NSString *)phone age:(int)age forID:(int)ID;
@end
Person类.m文件
#import "Person.h"
#import "DB.h"

@implementation Person
@synthesize name,ID,phone,age;
-(id)initWithName:(NSString *)aName phone:(NSString *)aPhone age:(int)aAge ID:(int)aID
{
    [super init];

    if (self)
    {
        self.name = aName;
        self.phone = aPhone;
        self.age = aAge;
        self.ID = aID;

    }
    return self;

}
-(NSString *)description
{
    return [NSString stringWithFormat:@"id = %d name = %@ phone = %@ age = %d",self.ID,self.name,self.phone,self.age ];
}

+(NSMutableArray *)findAll
{
    sqlite3 *db = [DB openDB];

    sqlite3_stmt *stmt = nil;//创建一个声明对象

    int result = sqlite3_prepare_v2(db, "select * from classDB order by ID ", -1, &stmt, nil);
    NSMutableArray *persons = nil;

    if (result == SQLITE_OK)
    {
        persons = [[NSMutableArray alloc]init];
        while (sqlite3_step(stmt) == SQLITE_ROW)
        {
            int ID = sqlite3_column_int(stmt, 0);

            const unsigned char *name = sqlite3_column_text(stmt, 1);
            const unsigned char *phone = sqlite3_column_text(stmt, 2);
            int age = sqlite3_column_int(stmt, 3);

            Person *p = [[Person alloc]initWithName:[NSString stringWithUTF8String:(const char *)name] phone:[NSString stringWithUTF8String:(const char *)phone] age:age ID:ID];
            [persons addObject:p];
            [p release];
        }
    }
    else
    {
        persons = [[NSMutableArray alloc]init];
    }
    sqlite3_finalize(stmt);
    return [persons autorelease];

}
+(int)count
{
    sqlite3 *db = [DB openDB];
    sqlite3_stmt *stmt = nil;
    int result = sqlite3_prepare_v2(db, "select count(ID) from classDB", -1, &stmt, nil);

    if (result == SQLITE_OK)
    {
        int count = 0;
        if (sqlite3_step(stmt))
        {
            count = sqlite3_column_int(stmt, 0);
        }
        sqlite3_finalize(stmt);
        return count;
    }
    else
    {
        sqlite3_finalize(stmt);
        return 0;
    }
}
+(Person *)findByID:(int)ID
{
    sqlite3 *db = [DB openDB];
    sqlite3_stmt *stmt = nil;
    Person *p = nil;
    int result = sqlite3_prepare_v2(db, "select * from classDB where ID = ?", -1, &stmt, nil);
    if (result == SQLITE_OK)
    {
        sqlite3_bind_int(stmt, 1, ID);
        if (sqlite3_step(stmt))
        {
            int ID = sqlite3_column_int(stmt, 0);
          &n

补充：移动开发 , IOS ,