计算机代考 Conceptual Model Mapping

Conceptual Model Mapping
Note: This table shows how to draw conceptual models. Do not use the notation marked with * in physical models.
Weak Entity
Chen¡¯s notation

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Crow¡¯s foot notation
Multivalued A.
{Attribute}
Composite A.
Attr. 1 Attr. 2
Name(A1, A2)
Derived A.
[Attribute]
Weak (or Partial) Key A.
Relationship
Weak (Identify- ing) Relationship

Relationship Cardinality/Constraints
Chen¡¯s notation
Crow¡¯s foot notation
Optional Many
Mandatory Many
Optional One
Mandatory One
BINARY Relationship Cardinalities
Here we have just looked at cardinalities and omitted participation constraints (optional/mandatory) for clarity
Many to Many
One to Many
One to One

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