diff --git a/pgsql/expected/pointcloud.out b/pgsql/expected/pointcloud.out
index ccdad3f..08367bf 100644
--- a/pgsql/expected/pointcloud.out
+++ b/pgsql/expected/pointcloud.out
@@ -96,5 +96,13 @@ SELECT PC_Envelope(pa) from pa_test;
  \x01030000000100000005000000b81e85eb51b8ae3fec51b81e85ebb13fb81e85eb51b8ae3f9a9999999999b93f0ad7a3703d0ab73f9a9999999999b93f0ad7a3703d0ab73fec51b81e85ebb13fb81e85eb51b8ae3fec51b81e85ebb13f
 (2 rows)
 
+SELECT PC_AsText(PC_Explode(PC_Patch(pt))) FROM pt_test;
+          pc_astext          
+-----------------------------
+ ( 1 : 0.01, 0.02, 0.03, 4 )
+ ( 1 : 0.02, 0.03, 0.03, 5 )
+ ( 1 : 0.03, 0.04, 0.03, 6 )
+(3 rows)
+
 --DROP TABLE pt_test;
 --DROP TABLE pa_test;
diff --git a/pgsql/pc_access.c b/pgsql/pc_access.c
index 2e050db..8214bdc 100644
--- a/pgsql/pc_access.c
+++ b/pgsql/pc_access.c
@@ -22,6 +22,9 @@ Datum pcpoint_agg_transfn(PG_FUNCTION_ARGS);
 Datum pcpoint_abs_in(PG_FUNCTION_ARGS);
 Datum pcpoint_abs_out(PG_FUNCTION_ARGS);
 
+/* Deaggregation functions */
+Datum pcpatch_unnest(PG_FUNCTION_ARGS);
+
 /**
 * Read a named dimension from a PCPOINT
 * PC_Get(point pcpoint, dimname text) returns Numeric
@@ -49,6 +52,20 @@ Datum pcpoint_get_value(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(DirectFunctionCall1(float8_numeric, Float8GetDatum(double_result)));
 }
 
+static bool
+array_get_isnull(const bits8 *nullbitmap, int offset)
+{
+	if (nullbitmap == NULL)
+	{
+		return false; /* assume not null */
+	}
+	if (nullbitmap[offset / 8] & (1 << (offset % 8)))
+	{
+		return false; /* not null */
+	}
+	return true;
+}
+
 PG_FUNCTION_INFO_V1(pcpatch_from_pcpoint_array);
 Datum pcpatch_from_pcpoint_array(PG_FUNCTION_ARGS)
 {
@@ -88,7 +105,7 @@ Datum pcpatch_from_pcpoint_array(PG_FUNCTION_ARGS)
 	for ( i = 0; i < nelems; i++ )
 	{
 		/* Only work on non-NULL entries in the array */
-		if ( (bitmap && (*bitmap & bitmask)) || !bitmap )
+		if ( ! array_get_isnull(bitmap, i) )
 		{
 			SERIALIZED_POINT *serpt = (SERIALIZED_POINT *)(ARR_DATA_PTR(array)+offset);
 			PCPOINT *pt;
@@ -113,16 +130,6 @@ Datum pcpatch_from_pcpoint_array(PG_FUNCTION_ARGS)
 			offset += INTALIGN(VARSIZE(serpt));			
 		}
 
-		/* Advance NULL bitmap */
-		if (bitmap)
-		{
-			bitmask <<= 1;
-			if (bitmask == 0x100)
-			{
-				bitmap++;
-				bitmask = 1;
-			}
-		}
 	}
 	
 	if ( pl->npoints == 0 )
@@ -254,4 +261,75 @@ Datum pcpoint_agg_final_pcpatch(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(result_final);
 }
 
+PG_FUNCTION_INFO_V1(pcpatch_unnest);
+Datum pcpatch_unnest(PG_FUNCTION_ARGS)
+{
+	typedef struct
+	{
+		int nextelem;
+		int numelems;
+		PCPOINTLIST *pointlist;
+	} pcpatch_unnest_fctx;
+
+	FuncCallContext *funcctx;
+	pcpatch_unnest_fctx *fctx;
+	MemoryContext oldcontext;
+
+	/* stuff done only on the first call of the function */
+	if (SRF_IS_FIRSTCALL())
+	{		
+		PCPATCH *patch;
+		SERIALIZED_PATCH *serpatch;
+		
+		/* create a function context for cross-call persistence */
+		funcctx = SRF_FIRSTCALL_INIT();
+
+		/*
+		* switch to memory context appropriate for multiple function calls
+		*/
+		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+		/*
+		* Get the patch value and detoast if needed.  We can't do this
+		* earlier because if we have to detoast, we want the detoasted copy
+		* to be in multi_call_memory_ctx, so it will go away when we're done
+		* and not before.      (If no detoast happens, we assume the originally
+		* passed array will stick around till then.)
+		*/
+		serpatch = PG_GETARG_SERPATCH_P(0);
+		patch = pc_patch_deserialize(serpatch);
+
+		/* allocate memory for user context */
+		fctx = (pcpatch_unnest_fctx *) palloc(sizeof(pcpatch_unnest_fctx));
+
+		/* initialize state */
+		fctx->nextelem = 0;
+		fctx->numelems = patch->npoints;
+		fctx->pointlist = pc_patch_to_points(patch);
+
+		/* save user context, switch back to function context */
+		funcctx->user_fctx = fctx;
+		MemoryContextSwitchTo(oldcontext);
+	}
+
+	/* stuff done on every call of the function */
+	funcctx = SRF_PERCALL_SETUP();
+	fctx = funcctx->user_fctx;
+
+	if (fctx->nextelem < fctx->numelems)
+	{
+		Datum elem;
+		PCPOINT *pt = fctx->pointlist->points[fctx->nextelem];
+		SERIALIZED_POINT *serpt = pc_point_serialize(pt);
+		fctx->nextelem++;
+		elem = PointerGetDatum(serpt);
+		SRF_RETURN_NEXT(funcctx, elem);
+	}
+	else
+	{
+		/* do when there is no more left */
+		SRF_RETURN_DONE(funcctx);
+	}
+}
+
 
diff --git a/pgsql/pointcloud--1.0.sql b/pgsql/pointcloud--1.0.sql
index 85201d7..64ee171 100644
--- a/pgsql/pointcloud--1.0.sql
+++ b/pgsql/pointcloud--1.0.sql
@@ -14,7 +14,7 @@ CREATE OR REPLACE FUNCTION PC_SchemaIsValid(xml text)
 
 -- Metadata table describing contents of pcpoints
 CREATE TABLE pointcloud_formats (
-    pcid INTEGER PRIMARY KEY,
+    pcid INTEGER PRIMARY KEY CHECK (pcid > 0),
     srid INTEGER, -- REFERENCES spatial_ref_sys(srid)
     schema TEXT 
 		CHECK ( PC_SchemaIsValid(schema) )
@@ -157,15 +157,8 @@ CREATE AGGREGATE PC_Point_Agg (
         FINALFUNC = pcpoint_agg_final_array
 );
 
-
--- CREATE FUNCTION pcpoint_array_from_pcpatch(pcpatch)
--- 	RETURNS pcpoint[] AS 'MODULE_PATHNAME', 'pcpoint_array_from_pcpatch'
--- 	LANGUAGE 'sql' IMMUTABLE STRICT;
+CREATE FUNCTION PC_Explode(pcpatch)
+	RETURNS setof pcpoint AS 'MODULE_PATHNAME', 'pcpatch_unnest'
+	LANGUAGE 'c' IMMUTABLE STRICT;
 	
--- The enumeration function
--- returns each element in a one dimensional integer array
--- as a row.
--- CREATE FUNCTION int_array_enum(int4[])
--- RETURNS setof integer
--- AS 'array_unnest'
--- LANGUAGE INTERNAL IMMUTABLE STRICT;
+
diff --git a/pgsql/sql/pointcloud.sql b/pgsql/sql/pointcloud.sql
index 22ae1bb..d5dbb19 100644
--- a/pgsql/sql/pointcloud.sql
+++ b/pgsql/sql/pointcloud.sql
@@ -72,5 +72,7 @@ INSERT INTO pa_test (pa) VALUES ('0000000001000000000000000200000006000000070000
 SELECT PC_AsText(pa) FROM pa_test;
 SELECT PC_Envelope(pa) from pa_test;
 
+SELECT PC_AsText(PC_Explode(PC_Patch(pt))) FROM pt_test;
+
 --DROP TABLE pt_test;
 --DROP TABLE pa_test;