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It's the first time here so I don't know if it's the right place to ask.. I'm not good in database design, just learning, so I'd like some advice if possible.

The case:

I'm building a really small application, a plugin, who's tables will likely have not too much records in real life (less than 50 in extreme situations), so performance is not crucial.

  • The user can create n Groups. A Group should have a 'hook' field.

  • For each Group, the user can create n BannerBoxes. So, a Group can have many BannerBoxes, a BannerBox can have only one group. Therefore a 1-many relation.

  • There can be n languages, and the Language table is already in place and has id_lang field. The language-group relation is 1 (language)-many (groups)

I'll often have to ask the db for all BannerBoxes saved for a certain language, grouped by Group. So, first find all Groups of a language, then for each Group, find its BanneBoxes.

I've thought about 2 solutions, but I cannot decide which could be better, and since I'm definitly a newbe, both could be just wrong.

a. Group entity with [hook, id_lang] fields; BannerBox entity with an [hook] field (desides the others). So when selecting, I can join the Group table with Language table on id_lang and then join with BannerBoxes on hook field.

b. Only the BannerBox entity, in this case with both [hook, id_lang] fields. I could join with Language by id_lang and then group by hook.

I also guess that a Group_BannerBox table [id_group, id_bannerbox] would be useless since I think it's a solution for many-many relations, am I right?

So, what would you do? a. or b.?

Thank you!

  • What is hook? Is it a unique property of Group? (it seems to be since you are using it in BannerBox instead of id_group). – ypercubeᵀᴹ Aug 11 '15 at 16:38
  • About the languages, can the BannerBoxes that belong to the same Group, have different languages? Or they should all have the same as their Group? – ypercubeᵀᴹ Aug 11 '15 at 16:39
  • :) thank you all for rapid and many answers! Hook is a field of Group, but cannot be used as primary id, as far as I can say. In practice, a hook is a 'place' on a website where I can put n bannerboxes. So itself, Group could even be the only field of a Group record. In fact, Group could be just Hook instead. BannerBoxs belonging to the same Group/Hook cannot have different languages. I'm using mysql, but this is just a general bd design question. – Luca Reghellin Aug 11 '15 at 17:23
  • @Stratboy so is hook equal to: max banners, left side bar, or max banners on left side bar? – Erik Aug 11 '15 at 18:08
  • @Erik: mmm please excuse me I can't understand your question. Probably being a newbe I lack some db terminology. I try to explain the real use case: hooks are a programming contruct used on the platform I'm building a plugin for. They help programmers to dynamically place pieces of html code in certain places on an page. For ex, a hook can be called 'headerhook', 'sidebarhook', etc.. In my case, the platform user will select a hook and then will create and assign bannerboxes (html boxes for showing banner slideshows) to that hook > that means, for ex: 'place those boxes on the home's sidebar'. – Luca Reghellin Aug 12 '15 at 7:47
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  • Create a User table with a UserId PK and any other user related fields.
  • Create a Language with a LanguageId PK and the name of the language.
  • Create a Group table with a GroupId PK, UserId FK, LanguageId FK, Hook? and any group specific fields.
  • Create a BannerBox table with a BannerBoxId PK, GroupId FK, and any other Banner Box specific fields

This will let you get all the information you need assuming that languages are consistent for a group.

I don't know what your Hook field is so answering @ypercube's comment would be helpful. In this answer I assumed it was some sort of business logic that was relevant at the group level.

  • And note that Group and User are reserved (and almost everywhere reserved) keywords, respectively.. – ypercubeᵀᴹ Aug 11 '15 at 17:02
  • @ypercube very true. Since the OP identified themselves as a newbie I'm glad you pointed that out otherwise my answer might have lead to frustration instead of assistance. I included them because they were the terms the OP used and the RDBMS I am most familiar with (SqlServer) allows you to escape reserved words if you want to use them for table names etc. – Erik Aug 11 '15 at 17:11
  • @ypercube Thanks for editing my answer to highlight the column and table names. I'll have to remember that mark down for future answers. – Erik Aug 11 '15 at 17:12
  • Yeah. All DBMS I know allow escaping, with either double quotes (the standard) or/and some other character. But it's cumbersome to have to quote every occurrence of a table. That's the only reason I kind of like plural names in tables (because of: Group, Order, User ;) – ypercubeᵀᴹ Aug 11 '15 at 17:13

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