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ERD To Data Model Transformation
The Entity Relationship Diagram (ERD) to Data Model transformation converts an ERD logical model to a data model targeted at the default database type, ready for generating DDL statements to run in one of the system-supported database products. Before doing the transformation, you define the common data type for each attribute and select a database type as the default database. You can then automatically generate the Data Modeling diagram.
The transformation uses and demonstrates support in the intermediary language for a number of database-specific concepts.
Concepts
Concept |
Definition |
See also |
|---|---|---|
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Table |
Mapped one-to-one onto Class elements. |
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Column |
Mapped one-to-one onto attributes. |
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Primary Key |
Lists all the columns involved so that they exist in the Class, and creates a Primary Key Method for them. |
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Foreign Key |
A special sort of connector, in which the Source and Target sections list all of the columns involved so that:
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Transform Foreign Keys |
Generalization
ERD technology can handle Generalization, as shown. Note that the copy-down inheritance is currently supported with two levels only.
Example
The ERD elements
After transformation, become the Data Model elements
Notes
- Sometimes you might go back to the ERD, make some changes and then need to do another transformation; in this case, to achieve better results, always delete the previous transformation Package before doing the next transformation