Implementing an Enterprise Data Dictionary Standard – Part II
You firstly need to create a new ERwin model (Logical / Physical), the chosen database platform is irrelevant at this stage, to keep ease of use, I normally use “ODBC/ generic”. Should you have a standard platform in your organisation you can make use of that platform as your physical platform. The main reason for the requirement of a physical portion of the model is to handle the transformation between the logical and physical of the abbreviations.
It is important to make effective use of the Domain Parents e.g. a ‘code’ domain type that has a data type of varchar 20 under the domain parent of string.
This is important in the future should you want to change a data type from one to another of similar type (i.e. text to character).
Once back on the Domain Dictionary screen you can then edit your domain (data dictionary standard). By editing the “Name Inherited by Attribute” you can change the name that will be given to the attribute, e.g. If you want the attribute to be lower case and prefixed by the entity name, use the following: %Lower(%OwnerEntity %AttDomain). In this article we will not be covering the ERwin macro language, but this is just an insight into this macro language that is at your disposal in ERwin.
You can then carry on with the Data Types, Constraints & Definitions, important to note that there are two definitions, one for the domain itself and another that is inherited by the attribute.
Once you have captured all your domains (standards), then save and close the file. Note that this file will not contain any entities or attributes, only the domains (Data Dictionary standards).
Open the file (or create new) for the data model that you want to use the domains in (this can be a logical / physical model or logical only or physical only)
Then you need to import your Enterprise Data Dictionary that you just created, to do this use the “Add Model Source” functionality, as shown in Figure 3.
On the next screen “Load” the Enterprise Data Dictionary, as in Figure 4.
Then press “Add” and close the Enterprise Data Dictionary when prompted. You will now have the imported domains in your model.
From here you can then drag the domains into your entities as you require, all the standards that you set will be inherited by the entity.