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 http://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 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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