[tracker] SPARQL: Fix queries with triples without variables

[Jürg Billeter <juergbi src gnome org>]

commit 6459741d5c7ecc9697b28a8ba0849fdfa40b2908
Author: Jürg Billeter <j bitron ch>
Date:   Mon Jun 29 14:37:03 2009 +0200

    SPARQL: Fix queries with triples without variables

 src/libtracker-data/tracker-sparql-query.vala |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index a3cd944..fc558cd 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -1029,6 +1029,13 @@ public class Tracker.SparqlQuery : Object {
 				bindings.append (binding);
 			}
 		}
+
+		if (triple.subject.type != Rasqal.Literal.Type.VARIABLE &&
+		    triple.predicate.type != Rasqal.Literal.Type.VARIABLE &&
+		    triple.object.type != Rasqal.Literal.Type.VARIABLE) {
+			// no variables involved, add dummy expression to SQL
+			pattern_sql.append ("1, ");
+		}
 	}
 
 	DataTable get_table (string subject, string db_table, bool share_table, out bool newtable) {