+At its core, the Assessment package defines a hierarchical container +model of a "survey", "questionnaire" or "form". This approach not only +follows the precedent of existing work; it also makes excellent sense +and no one has come up with a better idea. +
+ +We choose the terms Assessment-Sections-Items-Choices over +Surveys-Sectdions-Questions-Choices partly to reduce naming clashes +during the transition from Survey/Questionnaire packages, but mostly +because these terms are more general and thus suit the broader +applicability intended for this package. +
+As is the custom in the OpenACS framework, all RDBMS tables in +the package will be prepended with "as_" to prevent further prefent +naming clashes. Judicious use of namespaces will also be made in +keeping with current OpenACS best practice. +
+Several of the Metadata entities have direct counterparts in +the Data-related partition of the data model. Some standards (notably +CDISC) rigorously name all metadata entities with a "_def" suffix and +all data entities with a "_data" suffix -- thus "as_item_def" and +"as_item_data" tables in our case. We think this is overkill since +there are far more metadata entities than data entities and in only a +few cases do distinctions between the two become important. In those +cases, we will add the "_data" suffix to data entities to make this +difference clear. +
+A final general point (that we revisit for specific entities +below): the Assessment package data model exercises the Content +Repository (CR) in the OpenACS framework heavily. In fact, this use of +the CR for most important entities represents one of the main advances +of this package compared to the earlier versions. The decision to use +the CR is partly driven by the universal need for versioning and reuse +within the functional requirements, and partly by the fact that the CR +has become "the Right Way" to build OpenACS systems. Note that one +implication of this is that we can't use a couple column names in our +derived tables because of naming clashes with columns in cr_items and +cr_revisions: title and description. Furthermore we can handle versioning and internationalization through +the CR.
+ ++Here's a detailed summary view of the entities in the Assessment +package. Note that in addition to the partitioning of the entities +between Metadata Elements and Collected Data Elements, we identify the +various subsystems in the package that perform basic functions. +
+We discuss the following stuff in detail through the subsequent +pages, and we use a sort of "bird's eye view" of this global graphic to +keep the schema for each subsystem in perspective while homing in on +the relevant detail. Here's a brief introduction to each of these +section