Question

In my application whenever a user upload a wallpaper,i need to crop that wallpaper into
3 different sizes and store all those paths(3 paths for cropped images and 1 for original upload wallpaper) into my database.
I also need to store the tinyurl of the original wallpaper(one which is uploaded by user).

While solving the above described problem i come up with following table structure.

CREATE TABLE `wallpapermaster` (
  `wallpaperid` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `userid` bigint(20) NOT NULL,
  `wallpaperloc` varchar(100) NOT NULL,
  `wallpapertitle` varchar(50) NOT NULL,
  `wallpaperstatus` tinyint(4) DEFAULT '0' COMMENT '0-Waiting,1-approved,2-disapproved',
  `tinyurl` varchar(40) NOT NULL
) ENGINE=MyISAM

wallpaperloc is a comma separated field consisting of original wallpaper location plus locations of all cropped instances.

I know using comma separated field considered to be a bad design in the world of relational database,So Would you like to suggest some other neat and efficient ways?

Answer 1

Use a 1:n relationship between the wallpapermaster and a location table.

Something like this:

CREATE TABLE wallpapermaster (
  wallpaperid     int unsigned NOT NULL AUTO_INCREMENT,
  userid          bigint NOT NULL,
  wallpaperloc    varchar(100) NOT NULL,
  wallpapertitle  varchar(50) NOT NULL,
  wallpaperstatus tinyint DEFAULT '0' COMMENT '0-Waiting,1-approved,2-disapproved',
  primary key (wallpaperid)
) ENGINE=InnoDB;


CREATE TABLE wallpaperlocation (
  wallpaperid  int unsigned NOT NULL,
  location     varchar(100) NOT NULL,
  tinyurl      varchar(40),
  constraint fk_loc_wp 
      foreign key (wallpaperid) 
      references wallpapermaster (wallpaperid),
   primary key (wallpaperid, location)
) ENGINE=InnoDB;

The primary key in wallpaperlocation ensures that the same location cannot be inserted twice.

Note that int(10) does not define any datatype constraints. It is merely a hint for client application to indicate how many digits the number has.