ISSUE-37, ACTION-138: DBMS connection details in R2RML mappings


As we've been discussing, a given R2RML mapping is tied to a given
RDB schema, and indeed, to the data in that RDB at a point-in-time.

Given this, there are certain identifying characteristics of the
RDB schema that should be kept with (and I think, within) the 
R2RML mapping.

These may include --

- DB engine identifier
  -- as different SQL syntax may be needed against different
     engines.  there are ways to query the engine itself for
     identification including version, which allow tools such
     as R2RML engines to sculpt their SQL appropriately to 
     the RDB engine...
- DB host
  -- as there may be other instances on other hosts, with
     similar or even identical schema, but different content
- DB listening port
  -- as there may be multiple instances on the same host, with
     similar or even identical schema, but different content
- authenticating user ID
  -- as different users may see different tables, fields, 
     rows, etc., due to differing permissions

The above may well be an incomplete list!  I believe that R2RML
mappings (and their outputs) should also include notation of the 
datetime they were generated and/or valid, but this has been
controversial in conversation.

It has been suggested that a few fields might be used, possibly 
holding a JDBC Driver ClassName and the associated JDBC Connect 
String.  This is potentially problematic, as it assumes that 
every DBMS will have such a JDBC driver, and may suggest to 
users that every connection should be made thereby.

It has also been suggested that this information be optional, which
I could accept *if* the standard/spec states R2RML SHOULD include
such data (retains validity of existing mappings which lack it, 
and allows for justifiable exclusion in future mappings, but 
strongly discourages such lack.)

Input and discussion is very much welcomed.

Be seeing you,


A: Yes.            
| Q: Are you sure?
| | A: Because it reverses the logical flow of conversation.
| | | Q: Why is top posting frowned upon?

Ted Thibodeau, Jr.           //               voice +1-781-273-0900 x32
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Received on Tuesday, 12 July 2011 16:08:16 UTC