Changes between Initial Version and Version 1 of ReferentialIntegrity


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Timestamp:
03/05/07 03:43:10 (8 years ago)
Author:
ieslick
Comment:

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  • ReferentialIntegrity

    v1 v1  
     1(This discussion refers to ticket #3)
     2
     3Referential Integrity (the term used for this property in AllegroCache) refers to the property of a database that ensures when the referent of a reference is deleted from the database, the referrer is properly updated.  That is to say, if I have a persistent slot S of an instance A that contains the oid reference of another instance, B and B is deleted from the database, what then is the value of S? 
     4
     5Currently Elephant creates an object for which references to any of its members will be unbound.  One solution is to have a status slot in each persistent object that determines whether that object is valid.  A proxy 'null' object is created that fails to satisfy a predicate valid-object-p that all valid objects satisfy.
     6
     7Another option is to roll this in with an oid-class table (Ticket #25).  When an object is deleted the class table points to a common "null object".  We'd have to think about what the default behavior is for this object on creation, etc.
     8