erwin data modeller tutorial - forward engineering tool

In last post we have designed simple model of a bank and save it either locally or to data mart. But usually what you want to do with model is to export it to the database so it can be used by you and other developers. By export I actually mean creating all tables, relationships etc. in the database. ERwin’s export dialog is really sophisticated and allows you to properly set what you want to export. If you have not chosen target db engine do it now clicking on Database/Choose Database. If you have chosen your target db engine you are ready to export your model. Click on Tools select Forward Engineer and then Scheme generation. This dialog should pop up:

This dialog allows you to fully set up export. Here is description of main fields:

• Schema Generation file – any configuration you set up can be saved into XML file and used later. This is extremely useful when you have one file for creating tables, relationships etc. and one for dropping them. Thing is when you make changes to the model you have to recreate tables in the DB and in order to do so you have to drop them first (when you use PK and FK constraint you have to drop them in special order) and create them again. So just create two config export files – one for dropping and one for creating.
• In Option tab there are two windows: DB Schema Generation and Schema where you actually set up what is ERwin going to do. I recommend you focus on Table and Referential integrity in left window where you can set whether and what to create or drop. I also recommend to uncheck creation of ERwin triggers.
• On the bottom there are few buttons that might be interesting for you:
  • Filter allows you to filter out tables you do not want to be generated
    
  • Preview actually shows you the SQL query that will be sent to db
  • Generate will connect (ask to select connection) to the database. If you have already selected connection ERwin will NOT ask you again so if you want to export your model to different db you have to change in main window in Database/Database Connection…
    

One important thing is that you do not make changes to design directly in the database but you do them first in ERwin and then recreate tables changed. Developers tends to skip ERwin and make some little changes directly to the DB.
Well you know what is forward engineering tool. But what if you already have some tables in database and you want to create model according to them? ERwin allows you to reverse engineer your database and export all metadata from DB and get a model. Just click Tools/Reverse engineering tool… and short wizard will guide you through the process. In this post you have learnt how to use forward engineering tool to export your model into DB and reverse engineering tool to create model according to existing DB.