In the last few months, more and more database-design questions have been migrated over here to dba. There is an entity-relationship tag over in SO. It's widely used, and I think usefully so. Should the same tag exist in DBA?

I know that I could create the tag if I wanted to, provided I have the rep. But I also want to avoid tag pollution. That's why I'm starting this discussion. The pros and cons of a new tag deserve an airing before a new candidate for burnination gets launched.

Edit: Somehow I missed the existence of yesterday. While there's a subtle difference between an ER model and an ER diagram, it's too fine a point to be worth worrying about. I'm deciding that, for now at least, the erd tag covers the necessary ground.

  • Does entity-relationship imply anything meaningful that entity-framework does not?
    – Aaron Bertrand Staff
    Jul 16, 2013 at 11:48
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    I think of entity framework as the Microsoft's ORM and entity relationship as a data model representation.
    – gonsalu
    Jul 16, 2013 at 12:34
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    @Gonsalu -- Ditto here. I'm referring to entity-relationship Jul 16, 2013 at 12:44
  • +1 @WalterMitty for starting a discussion. I would also ask what we think the definition should be for the tag. That may help us to decide if we should have it or not. Jul 16, 2013 at 12:56
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    Ok, let me ask a slightly different question: have we had any posts on our site where this difference is important? Perhaps we should hold off until this concept has some traction here.
    – Aaron Bertrand Staff
    Jul 16, 2013 at 14:26
  • Basically, that's why I started the discussion: to see if the concept gets any traction. Over in SO, there are lots of questions about how a given case should be modeled. Some of these questions are at the conceptual level, like whether a relationship should be many to many or many to one. Others are at the logical level, dealing with questions of table composition. The latter could just as easily be tagged database design. The former could not. Jul 16, 2013 at 18:56
  • @Chris funny you should ask for a definition. I think, judging from the Q&A in SO, that the definition of ER modeling has been evolving. Back in the 1980s, ER modeling was implementation agnostic, and useful only for conceptual modeling. Nowadays people seem to be applying ER diagrams at least to conceptual data models, to logical data models, and even to physical data models. Jul 16, 2013 at 18:59
  • If I were trying to define the ER model, I would start with Peter Chen's publications. A simpler definition might come out of the Wikipedia article on ER model. That's very short. And I'm not sure I buy the Wikipedia definition. Jul 16, 2013 at 21:33
  • I would say this is very closely related to this question: meta.dba.stackexchange.com/questions/930/… Is the intention of this question to have a tag more focused on the artifact and less-so on the activity?
    – Joel Brown
    Jul 17, 2013 at 4:19
  • I'm not sure. I'm trying to figure out which tags are useful and which are not. I agree with the comment that SQL is a useless tag in DBA even if it might have been useful in SO. Every tag discriminates between questions that carry the tag and ones that don't. Useful tags may help by attracting the attention of people who are likely to have an answer. I'm still learning. Jul 17, 2013 at 10:53
  • With regard to the question on a data-modeling tag, the consensus seemed to be that it overlaps database-design in too many cases. While I'm not entirely convinced, I put a lot of stock in a consensus honestly arrived at. Jul 17, 2013 at 10:56
  • I have seen a lot of questions from people claiming to be beginners about entity-relationship diagramming / modeling / design. Most of these are currently tagged under database-design. Some beginners may not know what an erd is or an entity model is. They just know that they are supposed to get some help with entity relationships. I think entity-relationship would make the post more visible in searches. Jul 21, 2013 at 15:24

1 Answer 1


Tags exist to help people find answers to their questions. The limit of five is to make you consider what are the most pertinent tags. If the tag would help someone find the answer, we should use it.

On this site, query and sql are so commonplace as to be a garbage identifier, so I'm loathe to see those on questions, but they do fit so I don't pitch too much of a fit. Likewise database is a useless tag here. However, I don't think enough questions exist en-bulk that entity-relationship would become noise.

Having said that, I question entity-relationship as the tagname because it's rather long. Long tags are bad tags. Then again er is also a bad tag.

So, basically, it's ok to create the tag and I don't mind if we create the tag but I think it's a bad tag because there's a certain amount of code-smell associated with it. Doesn't make it wrong, just means to be cautious

But I also want to avoid tag pollution.

meh, that's what we're here for ;-)

  • How about er-model? Jul 16, 2013 at 19:15
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    Alternatively, how about conceptual-model, logical-model and physical-model? Jul 16, 2013 at 19:16
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    The actual named models might be better as they are more concrete and give end users a more exact picture of what you are asking about. I like it. Jul 16, 2013 at 19:29

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