--- a/src/main/scala/RDB2RDFMain.scala	Thu Jan 07 10:48:43 2010 -0500
+++ b/src/main/scala/RDB2RDFMain.scala	Thu Jan 07 11:09:08 2010 -0500
@@ -323,25 +323,24 @@
       case sparql.TableConjunction(list) => {
 	list.foldLeft(state)((incState,s) => mapGraphPattern(db, incState, s, enforceForeignKeys))
       }
-      case sparql.TableDisjunction(list) => {
+      case sparql.TableDisjunction(disjoints) => {
 	/* SPARQL UNIONs are treated as SQL subselects.
 	 * Set up initial state for this subselect.
 	 */
 	val unionAlias = sql.RelAlias(sql.Name("R_union" + state.joins.size))
-	val initDisjoints:Set[sql.Select] = Set()
 	val emptyState = R2RState(
 	  util.AddOrderedSet[sql.Join](), 
 	  Map[sparql.Var, SQL2RDFValueMapper](), 
 	  Set[sql.Expression]()
 	)
-	val unionVars = list.foldLeft(Set[sparql.Var]())((mySet,disjoint) => mySet ++ findVars(disjoint)).toList
+	val unionVars = disjoints.foldLeft(Set[sparql.Var]())((mySet,disjoint) => mySet ++ findVars(disjoint)).toList
 
-	/* Iterate over the disjoints, accumulating a state and a select for each
-	 * disjoint. The count is used for uniquely naming flags in the SELECTs
-	 * used to indicate which disjoint produced a tuple.
+	/* Map the disjoints to subselects.
+	 * <no> is used for uniquely naming flags in the SELECTs used to
+	 * indicate which disjoint produced a tuple.
 	 */
-	val (state2, disjoints, count) = list.foldLeft((state, initDisjoints, 0))((incPair,disjoint) => {
-	  val (outerState, outerDisjoints, no) = incPair
+	val (subselects, _) = disjoints.foldLeft((Set[sql.Select](), 0))((incPair,disjoint) => {
+	  val (subselects, no) = incPair
 	  val disjointState = mapGraphPattern(db, emptyState, disjoint, enforceForeignKeys)
 	  val disjointVars = findVars(disjoint)
 	  val disjointNo = sql.NamedAttribute(sql.PrimaryExpressionTyped(sql.Datatype.INTEGER,sql.Name("" + no)), sql.AttrAlias(sql.Name("_DISJOINT_")))
@@ -360,6 +359,19 @@
 	      case _ => Some(sql.ExprConjunction(disjointState.exprs))
 	    }
 	  )
+	  (subselects + subselect, no+1)
+	})
+
+	/* Bind variables to the attributes projected from the subselect; handle
+	 * corefs (equivalence with earlier bindings).
+	 * <no> is used for uniquely naming flags in the SELECTs used to
+	 * indicate which disjoint produced a tuple.
+	 */
+	val (state2, _) = disjoints.foldLeft((state, 0))((incPair,disjoint) => {
+	  val (outerState, no) = incPair
+	  val disjointState = mapGraphPattern(db, emptyState, disjoint, enforceForeignKeys)
+	  val disjointVars = findVars(disjoint)
+
 	  val disjointNoAliasAttr = sql.RelAliasAttribute(unionAlias, sql.Attribute(sql.Name("_DISJOINT_")))
 	  val disjointCond = sql.RelationalExpressionNe(sql.PrimaryExpressionAttr(disjointNoAliasAttr), sql.PrimaryExpressionTyped(sql.Datatype.INTEGER,sql.Name("" + no)))
 	  val outerState2 = disjointVars.foldLeft(outerState)((myState, v) => {
@@ -404,9 +416,9 @@
 	      R2RState(myState.joins, myState.varmap + (v -> mapper), myState.exprs)
 	    }
 	  })
-	  (outerState2, outerDisjoints ++ Set(subselect), no+1)
+	  (outerState2, no+1)
 	})
-	val subselect = sql.Subselect(sql.Union(disjoints))
+	val subselect = sql.Subselect(sql.Union(subselects))
 	R2RState(state.joins + sql.InnerJoin(sql.AliasedResource(subselect,unionAlias)), state2.varmap, state2.exprs)
       }
       case sparql.OptionalGraphPattern(gp) => {