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There are a few important model properties. This dialog box
allows you to view or edit the following properties: the model font
(its face and size), whether the primary keys migration mechanism
should be used, whether the border should be used while printing
the model.
Key migration is a mechanism when the primary key fields of the
parent table (entity) become a part of
the child table either getting into the primary key or not
depending on whether the identifying or non-identifying relationship is used.
The parent entity is requited for identifying
relationship while in case with non-identifying relationship
the NULL value is acceptable for the field corresponding to the
relationship.
Identifying relationships are shown with the help of continuous
lines, while Non-identifying Relationships are represented by
dotted lines. Entities that have no identifying parents are shown
with right corners, while the rest of entities have rounded
corners.
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