Changes between Version 5 and Version 6 of rfc29_desired_fields

Timestamp:

Aug 9, 2010, 4:20:30 AM (14 years ago)

Author:

wonder

Comment:

--

rfc29_desired_fields

@@ -10 +10 @@
 
 Common use cases:[[BR]]
-1. the client renders the layer: all fields can be ignored, only the geometry is required[[BR]]
+1. the client renders the layer: all (or most) fields can be ignored, only the geometry is required[[BR]]
 2. the client shows attribute table: all fields are required, the geometry can be ignored
 
@@ -40 +40 @@
 The method will return OGRERR_NONE as long as all the field names are able to be resolved, even if the method does not
 support selection of fields.
+
+The drivers supporting this method will return TRUE to OLCIgnoreFields ("IgnoreFields") capability.
 
 The method will be implemented at the level of OGRLayer class: it will resolve indexes of the fields and set the following new member variables which indicate what should be ignored. The flags will be stored within OGRFeatureDefn and OGRFieldDefn classes and available with these getter functions:
@@ -83 +85 @@
 This change is fully backwards compatible: OGR will continue to fetch geometry, style and all fields by default. Only applications using the proposed API will experience the new behavior.
 
-Initially, only some drivers (Shapefile and few others) will implement this RFC. There is no need to modify all existing drivers when adopting the RFC - drivers that do not consider the ignored fields will simply fetch all attributes as before.
+Initially, only some drivers (Shapefile and few others) will implement this RFC. There is no need to modify all existing drivers when adopting the RFC - drivers that do not consider the ignored fields will simply fetch all attributes as before. To check whether a driver supports this RFC, OLCIgnoreFields capability can be checked.
 
 ogr2ogr command line tool will make use of this RFC in cases it receives -select argument with a list of required fields. Other than the specified fields will be ignored.