Comments on: What is entity-relationship model?

By: vimal krishna

vimal krishna — Thu, 26 Jan 2012 09:21:58 +0000

This is a very good explanation, best i found. Thanks

By: Quassnoi

Quassnoi — Thu, 22 Dec 2011 07:50:18 +0000

@John: ER is a model of data organization. It’s not a tool (as in software tool). I don’t know what Lean & Six Sigma is, and project management is completeley unrelated to ER. Yes, MS Access is a viable solution for small applications.

By: John Ross

John Ross — Thu, 22 Dec 2011 02:55:37 +0000

Would MS Access be a viable candidate in smaller applications? It does much of the work for you. There are some Great mapping programs that can also interact with it, such as Visio.
How different is ER from some of the Process Improvement tools used for Lean & Six Sigma and Project Management?

By: Quassnoi

Quassnoi — Mon, 01 Mar 2010 08:17:47 +0000

@Goncalo: no, just missed :)

By: Gonçalo

Gonçalo — Mon, 01 Mar 2010 00:10:47 +0000

Very, very good article.

Just a note: do the arrows between the attributes in the marriage diagrams represent any concept, or have you just missed those?

By: Quassnoi

Quassnoi — Tue, 29 Dec 2009 13:30:33 +0000

@openfrog: MS Visio.

By: openfrog

openfrog — Tue, 29 Dec 2009 13:27:44 +0000

Thanks a lot for this great article. The first time I really feel I have understood what an ER-Diagram really is all about and how it works. I came here through StackOverflow.com.

May I ask, what tool did you use to create those diagrams?

By: Quassnoi

Quassnoi — Sat, 05 Dec 2009 13:08:30 +0000

@Praveen: with ER, you should define entities, relationships and attributes. The diagram in the link you provided shows the relational design which provides the tables layout (so that we can generate a database schema) but gives too few hints on what will be stored in the tables. What is Long_Fields on diagram above? Is it an entity or a relationship or an offloaded attribute? You cannot tell from the name of the fields and the table design.

By: Praveen

Praveen — Sat, 05 Dec 2009 05:35:04 +0000

Hi, I’m using the following format to design ER, after all it looks much alike the Table Structure design.

http://www.meds-sdmm.dfo-mpo.gc.ca/meds/Prog_Nat/NCIS/Definition/Ncis_ER_diagram.gif

(found this on google)

I’m wondering what’s the difference between ER and Table structure.
Thanks

By: uberVU - social comments

uberVU - social comments — Sun, 22 Nov 2009 08:43:01 +0000

Social comments and analytics for this post…

This post was mentioned on Twitter by HybridDBA: Nice ERD overview / review: http://bit.ly/Voj8Q…