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One of the major design features of OpenACS 5.6.0 is the explicit representation -of object identity. The reason I say "explicit -representation" is because the concept of object identity has been +of object identity. The reason I say "explicit +representation" is because the concept of object identity has been around forever. It is inherent to our problem domain. Consider the example of 3.x style scoping. The 3.x data models use the triple (user_id, group_id, scope) to identify an object. In the 5.6.0 data model this @@ -32,4 +32,4 @@ even capable of fully tracking the history of membership state.
The design choice of explicitly representing object identity with an integer primary key that is derived from a globally unique sequence is the key to eliminating redundant code and replacing it with generic object -level services.