向sqlite数据库插入和读取图片数据 (for ios)

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假定数据库中存在表 test_table(name,image), 下面代码将图片文件test.png的二进制数据写到sqlite数据库：
char *name = "test";
NSString * nameString = [NSString stringWithCString:name encoding:NSUTF8StringEncoding];
NSString * filePath = [[NSBundle mainBundle] pathForResource:nameString ofType:@"png"];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath])
{
    NSData * imgData = UIImagePNGRepresentation([UIImage imageWithContentsOfFile:filePath]);
    const char * sequel = "insert into test_table(name,image) values(?,?)";

    sqlite3_stmt * update;
    if (sqlite3_prepare_v2(database, sequel, -1, &update, NULL) == SQLITE_OK)
    {
        sqlite3_bind_text(update, 1, name, -1, NULL);
        sqlite3_bind_blob(update, 2, [imgData bytes], [imgData length], NULL);
        if( sqlite3_step(update) == SQLITE_DONE)
        {
           NSLog(@"已经写入数据");
        }
        sqlite3_finalize(update);
    }
}
else
{
    NSLog(@"文件不存在");
}

下面代码从数据库中读取图片二进制数据，然后显示图片：
const char * sequel = "select image from test_table where name=?";
sqlite3_stmt * getimg;
if (sqlite3_prepare_v2(database, sequel, -1, &getimg, NULL) == SQLITE_OK)
{
    char *name = "test";
    sqlite3_bind_text(update, 1, name, -1, NULL);
    if(sqlite3_step(getimg) == SQLITE_ROW)
    {
        int bytes = sqlite3_column_bytes(getimg, 0);
        Byte * value = (Byte*)sqlite3_column_blob(getimg, 1);
        if (bytes !=0 && value != NULL)
        {
            NSData * data = [NSData dataWithBytes:value length:bytes];
            UIImage * img = [UIImage imageWithData:data];
            UIImageView * aview =[[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, IMAGE_WIDTH, IMAGE_HEIGHT)];
            aview.image = img;
            [self.view addSubview:aview];
            [aview release];
         }
     }
     sqlite3_finalize(getimg);
}