8.5. Mapping from ORM to ER
Fully attributed IDEFIX schemas are essentially relational schemas displayed in a different notation. For this reason, Microsoft’s ORM Source Model solution treats IDEFIX as simply a different relational style. If you are using that tool, you can generate IDEFIX schemas from ORM schemas by automatically generating the relational schema, setting the drawing style to IDEFIX, and then noting any extra ORM rules as textual annotations.
If instead you need to manually generate IDEF1X schemas from ORM, follow the relational mapping (Rmap) procedure discussed in Chapter 11 to obtain a relational schema and then redraw it in IDEF1X.
Mapping from ORM to a true ER depends on the ER dialect (e.g., does it support Alary associations, ...
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