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By Rafael H. Schloming and Mark Thomas
+ +User directory
Sitewide administrator directory
Subsite administrator directory
TCL script directory
Data model
PL/SQL file
The primary limitation of the OpenACS 3.x user group system is that it -restricts the application developer to representing a "flat group" +restricts the application developer to representing a "flat group" that contains only users: The user_groups table may contain the group_id of a parent group, but parent-child relationship support is limited because it only allows one kind of relationship between @@ -20,12 +21,12 @@ scope, user_id, and group_id columns was used to identify the party. One disadvantage of this design convention is that it increases a data model's complexity by requiring the programmer -to:
add these three columns to each "scoped" table
define a multi-column check constraint to protect against data corruption -(e.g., a row with a scope value of "group" but a null +to:
add these three columns to each "scoped" table
define a multi-column check constraint to protect against data corruption +(e.g., a row with a scope value of "group" but a null group_id)
perform extra checks in Tcl and PL/SQL functions and procedures to check both the user_id and group_id values
The core of the Group Systems data model is quite simple, but it was -designed in the hopes of modeling "real world" organizations which +designed in the hopes of modeling "real world" organizations which can be complex graph structures. The Groups System only considers groups that can be modeled using directed acyclic graphs, but queries over these structures are still complex enough to slow the system down. Since almost