Olavk said most of what I wanted to, but he did it better. I want to further emphasize a couple of things though:
the more normalized your database model is, the harder it is to change that to reflect your new business needs.
Like Olavk said,this is not my experience. It is easier to start with a normalized database and adjust. Now when adjust I sometimes have permitted exceptions to the normal form to minimize the number of code changes, but I always prefer to start normalized even if he does not stay that way.
we're fine with inconsistent data,
In the databases I have worked with, this is absolutely never acceptable. I know in some areas it may be, but not where you really care about being right. Every application I have been a DBA for has wanted all of its data to be correct, and if it is inconsistent you know that some of it is wrong. As a DBA I certainly could not guarantee that the data was correct, but I could normally guarantee that it was consistent and that helps.
the more normalized your database model is, the harder it is to change that to reflect your new business needs.
Like Olavk said,this is not my experience. It is easier to start with a normalized database and adjust. Now when adjust I sometimes have permitted exceptions to the normal form to minimize the number of code changes, but I always prefer to start normalized even if he does not stay that way.
we're fine with inconsistent data,
In the databases I have worked with, this is absolutely never acceptable. I know in some areas it may be, but not where you really care about being right. Every application I have been a DBA for has wanted all of its data to be correct, and if it is inconsistent you know that some of it is wrong. As a DBA I certainly could not guarantee that the data was correct, but I could normally guarantee that it was consistent and that helps.