January 18, 2003 at 7:12 am
Hi guys.
I'm just wondering if there is already a thread like this. I want to know what you guys use as a diagramming tool for your database. I use MS Visio because I really like ORM. BTW, does anyone among you here use this language. I find it more intuitive than ER. It is conceptual and very easy to verbalize unlike ER which is closer to the physical implementation. Visit www.orm.net for more info.
Just two days ago, I downloaded CA's Erwin demo, another database digramming tool. It's significantly more robust than Visio. The reason I wanted another diagramming tool is the inability of visio to exclude migrated primary keys of a dependent table in the creation of the script. Although, I prefer to write my own script, sometimes I wonder what the heck is my using a database tool if don't use script generation feature of the tool. An example would make my case clear. Say I have Tables A, B and C. C is dependent on B which is dependent on A. The generated script produces table like this
Table A
A_id pk
Table B
A_id pk
B_id fk
Table C
A_id fk
B_id fk
C_id pk
If all those fields are identity, then imho it's much better that A_id is excluded from the TableC and TableC will reference just one field of TableB - B_id. Much to my dismay, the same happens on Erwin. So guys, I want your opinion on this. Do you allow this in your final physical design or you turn your dependent entities to independent during the physical implementation? I do the latter because that's what my books told me to do (books from Wrox) and it's more practical to migrate a single key than two or more.
When I look at the generated script from the tools mentioned above, I found out that relation integrity(cascade update, cascade delete, no action) is implented thru triggers rather than the ...on delete no action, on update cascade options of T-SQL. Which of the two is better. I've been using the latter but I just want to know the rationale behind the trigger.
Whew! I know this one is lenghty, unorganized and convoluted. I just hope that I can spring an interesting discussion about any of the subjects I mentioned.
"The way to get things done is not to mind who gets the credit for doing them." - Benjamin Howett
January 21, 2003 at 8:00 am
This was removed by the editor as SPAM
January 21, 2003 at 5:37 pm
I've tried Visio, is ok. Have not tried Erwin. Hopefully we'll get others with more lengthy opinions!
Andy
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