[ganesh15]

what are the advantages and disadvantages of top-down & bottom up design method.? Are there any dangers with either method?

-ganesh

[andrewst]

Originally posted by ganesh15
what are the advantages and disadvantages of top-down & bottom up design method.? Are there any dangers with either method?

-ganesh

Wow, that's an open-ended question! I'm not sure how you'd design a database from the bottom up though: it suggests that you'd first identify all the attributes/columns, and then pull them together into tables, then decide how the tables should be related... I've never seen anyone do that (though I suppose that is how normalisation is often taught, in a way).

I'd say 80% top down, 20% bottom up: mostly, you work from the requirements and go down into details; for some parts (e.g. interfaces with existing systems/databases) you will need to see what already exists and work out how to join that to your model, which is kind of bottom-up.

I have never started a database design by thinking: "now where shall I start this, top down or bottom up?"

Perhaps you need to be more specific about what you mean by "design", and what the top down and bottom up approaches mean to you.

[KillaCrab]

same thing if you are doing oodb design. except of course you have to deal with methods and inheritance.

anyways you can use both bottom up or top down depending on who your though process works.

[Lepanto]

By bottom-up, he means exactly that.

Yes, there are people designing databases like that. They start with all

the attributes and work their way up to tables.

In that approach, NORMALIZATION is being heavily relied on.

That's an inferior approach, in my opinion.

I believe the TOP-DOWN approach is better.