diff --git a/asterix-om/src/main/java/edu/uci/ics/asterix/om/functions/AbstractFunctionDescriptor.java b/asterix-om/src/main/java/edu/uci/ics/asterix/om/functions/AbstractFunctionDescriptor.java
index caf3b91..919d8c9 100644
--- a/asterix-om/src/main/java/edu/uci/ics/asterix/om/functions/AbstractFunctionDescriptor.java
+++ b/asterix-om/src/main/java/edu/uci/ics/asterix/om/functions/AbstractFunctionDescriptor.java
@@ -26,6 +26,8 @@
 
 public abstract class AbstractFunctionDescriptor implements IFunctionDescriptor {
 
+    private static final long serialVersionUID = 1L;
+
     @Override
     public abstract FunctionIdentifier getIdentifier();
 
@@ -59,7 +61,6 @@
     public ICopyAggregateFunctionFactory createAggregateFunctionFactory(ICopyEvaluatorFactory[] args)
             throws AlgebricksException {
         throw new NotImplementedException("Not Implemented");
-
     }
 
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
index 3de05f8..f869832 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
@@ -16,25 +16,26 @@
 import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
 
 public abstract class AbstractScalarAggregateDescriptor extends AbstractScalarFunctionDynamicDescriptor {
-    private static final long serialVersionUID = 1L;
-
+    private static final long serialVersionUID = 1L;    
+    
     @Override
     public ICopyEvaluatorFactory createEvaluatorFactory(final ICopyEvaluatorFactory[] args) throws AlgebricksException {
+        // The aggregate function will get a SingleFieldFrameTupleReference that points to the result of the ScanCollection.
+        // The list-item will always reside in the first field (column) of the SingleFieldFrameTupleReference.
+        ICopyEvaluatorFactory[] aggFuncArgs = new ICopyEvaluatorFactory[1];
+        aggFuncArgs[0] = new ColumnAccessEvalFactory(0);
+        // Create aggregate function from this scalar version.
+        FunctionIdentifier fid = AsterixBuiltinFunctions.getAggregateFunction(getIdentifier());
+        IFunctionManager mgr = FunctionManagerHolder.getFunctionManager();
+        IFunctionDescriptor fd = mgr.lookupFunction(fid);
+        AbstractAggregateFunctionDynamicDescriptor aggFuncDesc = (AbstractAggregateFunctionDynamicDescriptor) fd;
+        final ICopyAggregateFunctionFactory aggFuncFactory = aggFuncDesc.createAggregateFunctionFactory(aggFuncArgs);
+
         return new ICopyEvaluatorFactory() {
             private static final long serialVersionUID = 1L;
 
             @Override
             public ICopyEvaluator createEvaluator(IDataOutputProvider output) throws AlgebricksException {
-                // The aggregate function will get a SingleFieldFrameTupleReference that points to the result of the ScanCollection.
-                // The list-item will always reside in the first field (column) of the SingleFieldFrameTupleReference.
-                ICopyEvaluatorFactory[] aggFuncArgs = new ICopyEvaluatorFactory[1];
-                aggFuncArgs[0] = new ColumnAccessEvalFactory(0);
-                // Create aggregate function from this scalar version.
-                FunctionIdentifier fid = AsterixBuiltinFunctions.getAggregateFunction(getIdentifier());
-                IFunctionManager mgr = FunctionManagerHolder.getFunctionManager();
-                IFunctionDescriptor fd = mgr.lookupFunction(fid);
-                AbstractAggregateFunctionDynamicDescriptor aggFuncDesc = (AbstractAggregateFunctionDynamicDescriptor) fd;
-                ICopyAggregateFunctionFactory aggFuncFactory = aggFuncDesc.createAggregateFunctionFactory(aggFuncArgs);
                 // Use ScanCollection to iterate over list items.
                 ScanCollectionUnnestingFunctionFactory scanCollectionFactory = new ScanCollectionUnnestingFunctionFactory(
                         args[0]);
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java
index ae2a485..97f5d3a 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java
@@ -1,6 +1,6 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
@@ -8,7 +8,6 @@
 public class ScalarAvgAggregateDescriptor extends AbstractScalarAggregateDescriptor {
 
     private static final long serialVersionUID = 1L;
-    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "avg", 1);
     public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
         public IFunctionDescriptor createFunctionDescriptor() {
             return new ScalarAvgAggregateDescriptor();
@@ -17,6 +16,6 @@
 
     @Override
     public FunctionIdentifier getIdentifier() {
-        return FID;
+        return AsterixBuiltinFunctions.SCALAR_AVG;
     }
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarCountAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarCountAggregateDescriptor.java
index 6f3baa6..be50d26 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarCountAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarCountAggregateDescriptor.java
@@ -1,6 +1,6 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
@@ -8,7 +8,6 @@
 public class ScalarCountAggregateDescriptor extends AbstractScalarAggregateDescriptor {
 
     private static final long serialVersionUID = 1L;
-    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "count", 1);
     public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
         public IFunctionDescriptor createFunctionDescriptor() {
             return new ScalarCountAggregateDescriptor();
@@ -17,6 +16,6 @@
 
     @Override
     public FunctionIdentifier getIdentifier() {
-        return FID;
+        return AsterixBuiltinFunctions.SCALAR_COUNT;
     }
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java
index a71eb3c..1a4e970 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java
@@ -1,6 +1,6 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
@@ -8,7 +8,6 @@
 public class ScalarMaxAggregateDescriptor extends AbstractScalarAggregateDescriptor {
 
     private static final long serialVersionUID = 1L;
-    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "max", 1);
     public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
         public IFunctionDescriptor createFunctionDescriptor() {
             return new ScalarMaxAggregateDescriptor();
@@ -17,6 +16,6 @@
 
     @Override
     public FunctionIdentifier getIdentifier() {
-        return FID;
+        return AsterixBuiltinFunctions.SCALAR_MAX;
     }
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java
index 4beae60..7c62a37 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java
@@ -1,6 +1,6 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
@@ -8,7 +8,6 @@
 public class ScalarMinAggregateDescriptor extends AbstractScalarAggregateDescriptor {
 
     private static final long serialVersionUID = 1L;
-    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "min", 1);
     public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
         public IFunctionDescriptor createFunctionDescriptor() {
             return new ScalarMinAggregateDescriptor();
@@ -17,6 +16,6 @@
 
     @Override
     public FunctionIdentifier getIdentifier() {
-        return FID;
+        return AsterixBuiltinFunctions.SCALAR_MIN;
     }
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java
index f3d9d1a..3c49815 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java
@@ -1,6 +1,6 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
 import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
@@ -8,7 +8,6 @@
 public class ScalarSumAggregateDescriptor extends AbstractScalarAggregateDescriptor {
 
     private static final long serialVersionUID = 1L;
-    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "sum", 1);
     public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
         public IFunctionDescriptor createFunctionDescriptor() {
             return new ScalarSumAggregateDescriptor();
@@ -17,6 +16,6 @@
 
     @Override
     public FunctionIdentifier getIdentifier() {
-        return FID;
+        return AsterixBuiltinFunctions.SCALAR_SUM;
     }
 }