--- a/src/main/scala/RDB2RDFMain.scala	Thu Dec 17 00:40:45 2009 -0500
+++ b/src/main/scala/RDB2RDFMain.scala	Thu Dec 17 11:56:05 2009 -0500
@@ -165,9 +165,11 @@
 	      case OLit(l) => exprs += literalConstraint(objattr, l, dt)
 	      case OUri(u) => exprs += uriConstraint(objattr, u)
 	      case OVar(v) => {
-		// !! 2nd+ ref implies constraint
 		val binding = varConstraint(objattr, v, db, rel)
-		varmap += v -> binding
+		if (varmap.contains(v))
+		  exprs += PrimaryExpressionEq(varToAttribute(varmap, v), RValueAttr(objattr))
+		else
+		  varmap += v -> binding
 	      }
 	    }
 	  }

--- a/src/test/scala/RDB2RDFTest.scala	Thu Dec 17 00:40:45 2009 -0500
+++ b/src/test/scala/RDB2RDFTest.scala	Thu Dec 17 11:56:05 2009 -0500
@@ -49,6 +49,24 @@
     true
   }
 
+  test("<s> <p> ?x") {
+    val sparqlParser = Sparql()
+    val sparqlSelect = sparqlParser.parseAll(sparqlParser.select, """
+SELECT ?manager {
+<http://hr.example/DB/Employee/id.18#record>  <http://hr.example/DB/Employee#manager>    ?manager
+}
+""").get
+    val sqlParser = Sql()
+    val sqlSelect = sqlParser.parseAll(sqlParser.select, """
+SELECT R_manager.id AS A_manager
+       FROM Employee AS R_id18
+            INNER JOIN Employee AS R_manager
+ WHERE R_manager.id=R_id18.manager AND R_id18.id=18 AND R_manager.id IS NOT NULL
+""").get
+    assert(RDB2RDF(db, sparqlSelect, StemURI("http://hr.example/DB/"), PrimaryKey(Attribute(Name("id")))) === sqlSelect)
+    true
+  }
+
   test("?s <p> 18") {
     /* Literal foreign keys should probably throw an error,
      * instead does what user meant. */
@@ -69,6 +87,25 @@
     true
   }
 
+  test("?s1 <p> ?x . ?s2 <p> ?x") {
+    val sparqlParser = Sparql()
+    val sparqlSelect = sparqlParser.parseAll(sparqlParser.select, """
+SELECT ?emp1 ?emp2 ?sharedName {
+   ?emp1  <http://hr.example/DB/Employee#lastName>    ?sharedName .
+   ?emp2  <http://hr.example/DB/Employee#lastName>    ?sharedName
+}
+""").get
+    val sqlParser = Sql()
+    val sqlSelect = sqlParser.parseAll(sqlParser.select, """
+SELECT R_emp1.id AS A_emp1, R_emp2.id AS A_emp2, R_emp1.lastName AS A_sharedName
+       FROM Employee AS R_emp1
+            INNER JOIN Employee AS R_emp2
+ WHERE R_emp1.lastName=R_emp2.lastName AND R_emp1.id IS NOT NULL AND R_emp1.lastName IS NOT NULL AND R_emp2.id IS NOT NULL
+""").get
+    assert(RDB2RDF(db, sparqlSelect, StemURI("http://hr.example/DB/"), PrimaryKey(Attribute(Name("id")))) === sqlSelect)
+    true
+  }
+
   test("transform SQLbgp") {
     val sparqlParser = Sparql()
     val sparqlSelect = sparqlParser.parseAll(sparqlParser.select, """