A great Data Dictionary is a mandatory requirement for a great Data Modeling tools. ER-Designer has a great Data Dictionary. The data dictionary supports Native Data Types, User Defined Data Types, and most importantly Domains. Child domains are also supported.
ER-Designers Data Dictionary (aka the Data Dictionary ) can be exported from or imported to a Data Model. This allows the sharing of a common data dictionary in all of your data models, and your enterprise.
Each Data Model must have a single data dictionary. This is important for a number of reason. As an example: one of the main uses of a data dictionary is to maintain a consistent semantic meaning of columns names in data base schema. If there were more than data dictionary in a diagram, the binding of column name to semantic meaning would lost.
ER-Designers Data Dictionary system merges imported data dictionaries with the data models existing data dictionary. The above screen shot is the import merge control user interface. This gives the user complete control over the merging of the imported Data Dictionary with the one already in the Data Model.
On the left you can see two more screen shoots. On is the Domain pane in the Data Dictionary tree. And the other is list of the Entities that use a particular Domain. No more guessing where a particular column is used in you schema.