Explain Database Term Lists

Issue raised by: Mario Loffredo; M.Loffredo@CNUCE.CNR.IT; Mon, 13 Jan 1997 16:32:03 +0100

Since the Explain database appears to the origin as any other database supported by the target, if a target supports the TermListInfo category, does the term list for the Explain database exist? If so, what does it consist of?

Technically, there may be term lists corresponding to supported exp-1 Use attributes. For example there may be an ExplainCategory term list; the terms in the list would be the Explain categories supported. There may be a databaseName term list where the terms are the database names. Etc.

However, term lists are not really intended for databases such as an Explain database. True, ExplainCategory is a Use attribute, and a term list (or index) is often associated with a Use attribute. But usually a term list exists when you cannot easily predict the values of the list, not when there is a discrete, well-known set of potential values.

A term list for ExplainCategory would exist presumably to allow a client to determine the set of categories supported. This presumes that the client has implemented Scan (which would otherwise not be necessary, to support Explain). But one of the categories is 'categoryList'. A client would probably be more likely to try to determine the list of categories by first tring to retrieve the categoryList record. (Of course, there is no rule in Explain to the effect that a server must support categoryList.)