Translating from ER to Relationship Schema

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Translating from ER to Relationship Schema

• Adapted from Juliana Freire

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The easy part
Entity ? relation with attributes underlined
field is key Relationship -gt relation? special
situations Multi-valued and composite
attributes Weak entity sets ISA
relationships Relations that result from an
entity set and 1tomany relationship
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Translating Many-to-Many
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One to Many
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One to Many answer
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One to- Many
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One to Many with total participation
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Why not a new relation?
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Mapping many to many attribute
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Throw the attributes onto the relationship table
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1-to-many relationship with an attribute?
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Add it to the 1 side
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Translating Weak Entity Sets
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Translating ISA relationship as a tier
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Translating ISA one with all
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Which one?
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Participation Constraints
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Splitting tables is always an option
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Sample ERD
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Equivalent Relational Schema
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Translate This
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Translation steps
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