Changes between Version 6 and Version 7 of rfc28_sqlfunc

Timestamp:

Aug 5, 2010, 12:48:32 PM (14 years ago)

Author:

warmerdam

Comment:

finalize for proposal phase.

rfc28_sqlfunc

@@ -3 +3 @@
 Author: Frank Warmerdam[[BR]]
 Contact: warmerdam@pobox.com[[BR]]
-Status: Development
+Status: Proposed
 
 == Summary ==
@@ -14 +14 @@
 SELECT (subtotal+salestax) as totalcost from invoice_info where 100 <= (subtotal+salestax)
 }}}
+
+A prototype implementation is now available for review in http://svn.osgeo.org/gdal/sandbox/warmerdam/gdal-rfc28 
 
 == Technical Approach ==
@@ -86 +88 @@
 == Compatability Implications ==
 
-There are no anticipated backward compatability problems.  For the most part the change results in some OGR SQL statements to work that would previously have generated an error. 
+Some identifiers that were previously allowed as unquoted field names will likely now have to be quoted as they will be keywords in the grammar.  The keyword set is:
+
+* IN
+* LIKE
+* NULL
+* IS
+* SELECT
+* LEFT
+* JOIN
+* WHERE
+* ON
+* ORDER
+* BY
+* FROM
+* AS
+* ASC
+* DESC
+* DISTINCT
+* CAST
+
+The previous implementation was written in C and avoided all use of GDAL/OGR services so that it could be easily used in other contexts, including as the where clause evaluator of the OGDI library.  After this update the code is C++, and direct use of CPL error and other services has been directly incorporated.  This means the implementation used by GDAL and OGDI will diverge. 
+
+For the most part the change results in some OGR SQL statements to work that would previously have generated an error. 
 
 == Performance Implications ==
 
 I am hopeful that the evaluation speed will not be significantly different for simple selections, but each output field will need to be evaluated as an expression (with presumably one value-from-field node).
-
 
 == Implementation Plan ==
@@ -99 +122 @@
 == Testing == 
 
-All existing OGR SQL test suite tests should pass, and autotest/ogr/ogr_sql_test.py and perhaps other scripts will be extended for the new capabilities. 
+All existing OGR SQL test suite tests should pass.  A new autotest/ogr/ogr_sql_rfc28.py script will be introduced to test new functionality.
 
 == Documentation ==