Generating ERDs from Conceptual or Physical Design?

[jason wilks]

Hello, I am designing a new database (from scratch) for an application that is still in the UI design phase and development is just starting. I have gathered all the requirements that I can and have created a conceptual design doc (a word document) that lists all the entities, attributes, and relationships, with some rules, standards, etc. It is very incomplete since the app design is still being worked on. We are then creating an ERD based on changes we make to the design document.

I have yet to do any physical design, but was thinking I should build the DDL scripts (and create test data) for the entity set I have defined in the document so far. A lot of database design best practices say to complete the logical design in full before moving onto physical design but I am thinking this is outdated practices.

As far as keeping the ERD up to date and simplifying the maintenance of it, the process I have seems too much work and not simple (I update the conceptual document in Word and then the ERD is generated (by another person) based on changes to the Word doc. I was thinking maybe I should just start building ddl scripts in mySql workbench and then the ERD could possibly be autogenerated with the ERD tool (they are using draw i/o).
I could still maintain the document since I think it's good to have an overall written design, but I wanted to ask and see what everyone thought about this process and what are some of the common procedures for a brand new project (no existing database exists) in its early stages. Thought or tips anyone?

Thanks, J