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Database Design

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Design Syntax Reference

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Diagram ::= Element+

  Element ::=
     "ENTITY"        Name                 Attributes
   | "WEAK" "ENTITY" Name Support+        Attributes
   | "ISA"           Name SuperEntity     Attributes
   | "RELATIONSHIP"  Name RelatedEntity+  Attributes

  Attributes ::=
     ":" Attribute*            # attributes start after colon 
   |                           # no attributes at all, no colon needed
    
  RelatedEntity ::= Arrow Entity ("(" Role ")")?   # optional role in parentheses
  Support ::= Entity WeakRelationship
  
  Arrow ::= "--" | "->" | "-)"
  Attribute ::= Ident | "_"Ident
  Entity, SuperEntity, Relationship, WeakRelationship, Role ::= Ident