Changes between Initial Version and Version 1 of ReferentialIntegrity

Show
Ignore:
Timestamp:
03/04/07 19:43:10 (7 years ago)
Author:
ieslick
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • 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