def verifyFieldList( fnames, fids = nil, dbid = @dbid )
     getSchema( dbid )
     @fids = @fnames = nil

     if fids
        if fids.is_a?( Array ) and fids.length > 0
            fids.each { |id|
               fid = lookupField( id )
               if fid
                  fname = lookupFieldNameFromID( id )
                  @fnames ||= []
                  @fnames << fname
               else
                  raise "verifyFieldList: '#{id}' is not a valid field ID"
               end
            }
            @fids = fids
         else
            raise "verifyFieldList: fids must be an array of one or more field IDs"
         end
     elsif fnames
        if fnames.is_a?( Array ) and fnames.length > 0
         fnames.each { |name|
            fid = lookupFieldIDByName( name )
            if fid
               @fids ||= []
               @fids << fid
            else
               raise "verifyFieldList: '#{name}' is not a valid field name"
            end
         }
         @fnames = fnames
       else
         raise "verifyFieldList: fnames must be an array of one or more field names"
       end
     else
        raise "verifyFieldList: must specify fids or fnames"
     end
     @fids
   end
def verifyFieldList( fnames, fids = nil, dbid = @dbid )
     getSchema( dbid )
     @fids = @fnames = nil

     if fids
        if fids.is_a?( Array ) and fids.length > 0
            fids.each { |id|
               fid = lookupField( id )
               if fid
                  fname = lookupFieldNameFromID( id )
                  @fnames ||= []
                  @fnames << fname
               else
                  raise "verifyFieldList: '#{id}' is not a valid field ID"
               end
            }
            @fids = fids
         else
            raise "verifyFieldList: fids must be an array of one or more field IDs"
         end
     elsif fnames
        if fnames.is_a?( Array ) and fnames.length > 0
         fnames.each { |name|
            fid = lookupFieldIDByName( name )
            if fid
               @fids ||= []
               @fids << fid
            else
               raise "verifyFieldList: '#{name}' is not a valid field name"
            end
         }
         @fnames = fnames
       else
         raise "verifyFieldList: fnames must be an array of one or more field names"
       end
     else
        raise "verifyFieldList: must specify fids or fnames"
     end
     @fids
   end
Given an array of field names or field IDs and a table ID, builds an array of valid field IDs and field names.
 Throws an exception when an invalid name or ID is encountered.