Hi,
I'm currently working on argouml-sql. Since I had the same ideas (and
made some mistakes) when beginning I think I need to correct some
points: (see below)
Am 25.03.2007, 14:10 Uhr, schrieb nett .by <[EMAIL PROTECTED]>:
Hi Linus!
I will try to describe my idea with more particular:
Entity Relationship Diagram (ERD) is a type of diagram, where you
describe
the db structure:
-Every entity in this diagram is a separate table in db
When designing a n:m-relation this approach doesn't work. You need
a third table between the two that have been modelled.
-In every entity you can specify columns and types of columns
-You can define primary keys and foreign keys
Foreign keys are not part of an entity relationship diagram. They
occur in relational models.
-You also can specify One-to-One, One-to-Many or Many-to-Many
Relationships between entities
When modelling an ERD you can do it. When modelling a relational
model n:m-relations simply don't exist.
There are three types of data models:
1. Conceptual model - entity relationship diagram for example
2. Logical model - relational model or network model for example
3. Physical model - model used by DBMS for data storage - contains
indices for example
As Tom Morris stated in another post an UML class diagramm corresponds
to an entity relationship diagram - the only difference is that another
notation is used.
Kai
-etc.
After creating Entity Relationship Diagram you can generate db by
choosing
db type (additionally indicate or load driver for this db).
You also can reverse existing db into ERD by connecting to db, choosing
db
tables and represent them in ERD.
One more very good feature, i think, will be the generation of class
diagram
from ERD, or generating ERD from class diagram.
This will help to accelerate the application development which use data
bases.
--
Müritz COMP Greifswald Computersystemhaus GmbH
An der Jungfernwiese 2
17489 Greifswald
Registergericht: Amtsgericht Stralsund
Registernummer: HRB 4035
Geschäftsführer: Alexander Lang, Torsten Marx
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
