Server Design

1
Server Design

• Arcs and Sub Entities

2
ER Diagram
3
Transformation Options for Exclusivity
Supertype and subtypes
TITLE

• Supertype
• Explicit subtypes
• Implicit subtypes
• Arcs

MOVIE
GAME
4
The Supertype Option
TITLE PRODUCT CODE TITLE
MOVIE CATEGORY . . . o AUDIO
GAME CATEGORY . . . o MINIMUM MEMORY
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Supertype Option
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Result of Supertype Option
Discriminator Column
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The Explicit Subtype Option
TITLE PRODUCT CODE TITLE
MOVIE CATEGORY . . . o AUDIO
GAME CATEGORY . . . o MINIMUM MEMORY
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Implementing Explicit Subtypes

• Select the In Set check box for the subtypes only

Table Mappings
In Set
No Mapping
TITLE
Included
--GAME
--MOVIE
Included
9
The Implicit Subtype Option(rare and not
recommended)
TITLE PRODUCT CODE TITLE
MOVIE CATEGORY . . . o AUDIO
GAME CATEGORY . . . o MINIMUM MEMORY
10
Implementing Implicit Subtypes

• Select the In Set check box for the supertype and
  the subtypes

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The Ordinary Arc
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The Result
13
The Arc Option(rarely applicable)
TITLE PRODUCT CODE TITLE
MOVIES MO_ID CATEGORY . . . o AUDIO
MOVIE CATEGORY . . . o AUDIO
TITLES PRODUCT_CODE TITLE . . . o
MO_MO_ID o GA_GA_ID . . .
GAMES GA_ID CATEGORY . . .
o MINIMUM_MEMORY
GAME CATEGORY . . . o MINIMUM MEMORY
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Implementing ArcsFirst Run

• Include supertypes and subtypes

• Choose tables only

15
Implementing ArcsSecond Run

• Map the arc

• Select tables, columns, and keys

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Choosing Implementation