Comments on: Where’s your database’s ER Diagram?

By: Craig

Craig — Mon, 25 Jun 2012 18:19:04 +0000

I am a former developer turned data modeler for a large retailer. For our primary and secondary enterprise applications we do our best to keep the data models in sync. We use ERwin so the data models are kept in the proprietary repository. For active projects we are constantly doing compares and updates to the model and database. When those tasks are done we then export the model (logical and physical) to a pdf or html report and place it in a central place for the project team so that they are always up to date. Our company has seen some good lift from having well documented databases especially when bringing on new folks. It helps them to get oriented to the terms (all/most of the columns are defined) and what they mean as well as giving them a sense for what the business is doing.

By: ChrisW

ChrisW — Tue, 19 Jun 2012 15:08:27 +0000

“… Furthermore, it can be difficult to create an ER diagram for an existing database, especially if you were not involved in its creation…”

Depends on your RDBMS and tools, but Oracle’s free SQLDeveloper tool allows you to reverse engineer an ERD from an existing Oracle schema, and you can then use the logical/physical models for ongoing development e.g. to generate SQL for subsequent changes to the model. There are probably similar tools for other RDBMS platforms.

Of course, this is only useful if your DB schema has been constructed with proper constraints, primary keys, foreign keys etc, which can be surprisingly rare on smaller projects in Javaland!

By: Where’s your database’s ER Diagram? « Another Word For It

Where’s your database’s ER Diagram? « Another Word For It — Mon, 04 Jun 2012 21:32:40 +0000

[…] Where’s your database’s ER Diagram? by Scott Selikoff. […]

By: Charles

Charles — Mon, 04 Jun 2012 19:13:05 +0000

Have your ER diagram generated automatically during everybuild…use schema spy.

We generate our schema using liquibase and our entities directly from the db schema using hibernate tools. By adding schema spy to the build we always have an up to date view of the current schema.