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Converting a Physical Data Model to a Logical Model

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Table of Contents Setting up the subject area (if required) 2 Bringing in the tables 4 Assigning appropriate Domains 5 The logical Model 6 Identifying a many to many relationship 7 Replacing a mapping table 7 Renaming Logical Model 15 Entity Names 15 Relationship Names 16 Attribute Names 16 Revisiting Physical Model 19 Relationship Naming 20 FINAL PRODUCT 21 Logical VS Physical 21

Setting up the subject area (if required) 1. Open the target and source Erwin models in the same instance of Erwin. 2. If required create a new subject area in the target model where the tables are going to be copied.

Figure 1 – Creating a new subject area

3. Change the default theme to ‘Classic Theme’ (right click …show more content…

8. Create the rest of the columns as they exist in the old mapping table; often you should be able to just drag the columns from the older mapping table into the new mapping table. The below diagram used the dragging mechanism.

Figure 11 – Creating/Dragging columns from old to new mapping table 9. Create the primary key in the new mapping table, the new primary key column should be named exactly as the older one. When you try to add the primary key the below box might appear, if you see the box below select the ‘Rolename migrating attribute’ and name the attribute as if it is a FK column originating from the new mapping table, ‘SAVE_VLS_STATUS_PARAMETERS_MAPPING_ID’ in this case.

Press OK Press OK

10. Assign this new column to be the PK. 11. After closing the dialogue box you should have the below image.

12. Remove the old mapping table, please remember to delete the relationships going into or originating from the old mapping table before deleting the table. While deleting you will see the below dialogue box appear, press yes.

13. After deleting the older objects your diagram should like the image below.

Figure 12 – New mapping table

14. Your logical model will look like it does below.

Renaming Logical Model
Entity Names 1. For ref tables, remove the prefix ref from the entity name. will become 2. Replace the underscores with a space ‘ ‘ from the new name. will

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