Difference between UML & ER Modelling

Difference between UML & ER Modelling

Post by dgpin.. » Tue, 03 Aug 1999 04:00:00



Please forgive my cluelessness. I am trying to
learn the difference between modelling
methodologies; UML vs. Entity Relationship.

The context:We are a prospective web start-up.  My
background is on the Product/Application side (not
a programmer or DBA).  I am trying to develop a
detailed spec for a new web-based appl that we
hope to get developed.  It is a database oriented
appl, and we have tentatively focused on Oracle8i,
and Sun/Solaris.  I understand tables, columns,
etc., and ER makes some sense to me.  I just want
to know which approach is more appropriate for
developing our appl.  ( also of note: appl will be
developed focusing on server-side java
(EJB's,servlets, JSP's).

Thank you for your interest.

David

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

 
 
 

Difference between UML & ER Modelling

Post by dgpin.. » Tue, 03 Aug 1999 04:00:00


Please forgive my cluelessness. I am trying to
learn the difference between modelling
methodologies; UML vs. Entity Relationship.

The context:We are a prospective web start-up.  My
background is on the Product/Application side (not
a programmer or DBA).  I am trying to develop a
detailed spec for a new web-based appl that we
hope to get developed.  It is a database oriented
appl, and we have tentatively focused on Oracle8i,
and Sun/Solaris.  I understand tables, columns,
etc., and ER makes some sense to me.  I just want
to know which approach is more appropriate for
developing our appl.  ( also of note: appl will be
developed focusing on server-side java
(EJB's,servlets, JSP's).

Thank you for your interest.

David

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

 
 
 

1. UML vs. ER modelling (long)

Hi all,

I recently took over this project, which was started by someone else a
few months before. All the major architectural and technological
choices were already made when I joined i.e., J2EE (with a pre-2.0 EJB
container :-(), Oracle 9i, entirely Web-based system with servlets and
JSP, OOA&D with UML and a USDP-like methodology. It's a huge business
information system for a large multinational company, covering nearly
all aspects of the company's business, which includes supplies, active
invoicing, recording of suppliers' invoices, product configuration,
offers, orders, asset management, etc.

When I joined the project I found out that my predecessor had analysts
use UML for everything, which means class diagrams for static stuff,
activity and sequence diagrams for business process modelling, and so
on. So far, so good. I'm a long-time UML user, and I've succesfully
applied it to very diverse application domains so I'm entirely
familiar with it. However, at a closer look this system showed the
following characteristics:
 - extremely data-centric, the data model being much more complicated
than the business processes
 - a very very complicated data model, actually one of the most
intricate I've ever seen
 - most (say about 80-85%) transactions are dumb, CRUD-like, real biz
logic only covering the remaining 15-20%

Now my question is: What methodology/notation/approach to use?
Alternatives include:
1. sticking to UML for everything. This has the big advantage of
having one, cohesive environment (for example, you can draw sequence
diagrams involving objects instantiating classes from the analysis
diagrams). However, eventually you have to design an e-r model for
your persistent data, and this means an extra burden (at least while
the UML profile for data is not finalised)
2. using an E-R tool for data (such as E-R Studio, E-Rwin, etc.) while
still using UML for dynamic diagrams (activity, etc.). This would save
a lot of time by allowing one to directly defining data at the
relational level, but would somewhat reduce cohesiveness. "Real" UML
would be used only for the 15-20% including real business logic. In
other words: Why should I use UML to model classes that will never
have a run-time image in the form of Java objects, but that will only
exist as tables in a DB? Wouldn't it be better to just model those
directly in E-R and use UML only where it's really needed?

Any suggestions out there?

Thanks a lot in advance,
andy

2. ORA-01001 and MAXOPENCURSORS

3. Technical Author, Microsoft Office, German, English, Contract

4. ER vs UML, disadvantage of UML

5. Problem with Calc Measures and Custom Rollups

6. Dimensional modelling or ER modelling for Data warehouse design

7. "set identity_insert on" with non dbo user

8. UML modelling

9. mapping ER models to UML class diagrams

10. NH-Bedford-266681--Client/Server-SQLSERVER-PowerBuilder-UML-COM-DCOM-CORBA-Visua

11. Disadvantages ORM/UML/ER

12. New ER Modelling tool for Delphi