Re: Re-opening ISSUE-22 on vendor-specific SQL

 My current proposed solution for this is:

* by default SQL queries in R2RML are expected to be SQL 2008 compliant.

* SQL queries that make use of vendor specific SQL constructs are flagged as
"vendor specific". To support validation, vendor specific queries can
include a property in the mapping that defines the names of the columns
projected by the query.

I don't feel a need to try and identify what vendor the SQL complies with in
these cases, but merely that it is vendor specific.

This solution fits well with a use-case in which most of the queries are
standard but a few use vendor specific constructs. Most of the queries can
be parsed by the R2RML implementation (this is useful for validation and
optimization). The few queries with vendor specific constructs can be simply
passed through to the database engine as "opaque" queries. Using this
approach in conjunction with an eventual (post R2RML 1.0) solution for SQL
composition in the mapping allows the mapper to isolate vendor specific SQL
in small, reusable queries and keep the bulk of the SQL in SQL 2008
compliant queries.


Received on Tuesday, 31 May 2011 13:23:56 UTC