[Nitro] schema_inheritance

Emmanuel Piperakis epiperak at softlab.ece.ntua.gr
Sun Dec 25 12:00:23 EST 2005


Trans,
what it does is,

in the case of subclasses if in the superclass you include the line 
schema_inheritance Og create 1 table for all the subclasses and puts the 
UNION of all properties in this table + one new column called ogtype that 
distinguishes the subclass by holding the .class of the subclass (aka the 
name of the Subclass). If schema inheritance is not used then each class 
and subclass has its own table.

eg. (to use the same example)

class Project
  property :xmas, String
  schema_inheritance
end

class ForeignProject < Project
  property :gift, String
end

class DomesticProject < Project
  property :santa, String
end

Og creates one table with the following columns (at least for version 0.25 
and NOT for 0.26)

ogtype
ogxmas
oggift
ogsanta
oid

schema_inheritance is necessary for certain kind of queries... do not ask 
me not to use it as a solution... ;-)

Thanks for your patience...



Emmanouil Piperakis (epiperak at cs.ntua.gr)
{To explore is Human, to Create is Devine,
  To teach is Primal, to Rule is Sin}



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