diff --git a/src/vnode/common/inc/dataformat.h b/src/vnode/common/inc/dataformat.h
index 30246bc16c..c2c4134bd8 100644
--- a/src/vnode/common/inc/dataformat.h
+++ b/src/vnode/common/inc/dataformat.h
@@ -12,7 +12,7 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
-#if !defined(_TD_DATA_FORMAT_H_)
+#ifndef _TD_DATA_FORMAT_H_
 #define _TD_DATA_FORMAT_H_
 
 #include <stdint.h>
@@ -24,14 +24,26 @@ extern "C" {
 #endif
 // ----------------- Data row structure
 
-/* A data row, the format of it is like below:
+/* A data row, the format is like below:
  * +---------+---------------------------------+
  * | int32_t |                                 |
  * +---------+---------------------------------+
- * |   len   |               data              |
+ * |   len   |                row              |
  * +---------+---------------------------------+
+ * len: the length including sizeof(row) + sizeof(len)
+ * row: actual row data encoding
  */
-typedef char* SDataRow;
+typedef void *SDataRow;
+
+#define dataRowLen(r) (*(int32_t *)(r))
+#define dataRowTuple(r) ((char *)(r) + sizeof(int32_t))
+#define dataRowSetLen(r, l) (dataRowLen(r) = (l))
+#define dataRowIdx(r, i) ((char *)(r) + i)
+
+SDataRow tdNewDataRow(int32_t bytes);
+SDataRow tdNewDdataFromSchema(SSchema *pSchema);
+void     tdFreeDataRow(SDataRow row);
+int32_t  tdAppendColVal(SDataRow row, void *value, SColumn *pCol, int32_t suffixOffset);
 
 /* Data rows definition, the format of it is like below:
  * +---------+---------+-----------------------+--------+-----------------------+
@@ -40,7 +52,7 @@ typedef char* SDataRow;
  * |   len   |  nrows  |        SDataRow       |  ....  |        SDataRow       |
  * +---------+---------+-----------------------+--------+-----------------------+
  */
-typedef char * SDataRows;
+typedef void *SDataRows;
 
 /* Data column definition
  * +---------+---------+-----------------------+
@@ -49,7 +61,7 @@ typedef char * SDataRows;
  * |   len   | npoints |          data         |
  * +---------+---------+-----------------------+
  */
-typedef char * SDataCol;
+typedef char *SDataCol;
 
 /* Data columns definition
  * +---------+---------+-----------------------+--------+-----------------------+
@@ -58,24 +70,24 @@ typedef char * SDataCol;
  * |   len   | npoints |        SDataCol       |  ....  |        SDataCol       |
  * +---------+---------+-----------------------+--------+-----------------------+
  */
-typedef char * SDataCols;
+typedef char *SDataCols;
 
 typedef struct {
-    int32_t rowCounter;
-    int32_t totalRows;
-    SDataRow row;
+  int32_t  rowCounter;
+  int32_t  totalRows;
+  SDataRow row;
 } SDataRowsIter;
 
 // ----------------- Data column structure
 
 // ---- operation on SDataRow;
-#define TD_DATA_ROW_HEADER_SIZE  sizeof(int32_t)
+#define TD_DATA_ROW_HEADER_SIZE sizeof(int32_t)
 #define TD_DATAROW_LEN(pDataRow) (*(int32_t *)(pDataRow))
 #define TD_DATAROW_DATA(pDataRow) ((pDataRow) + sizeof(int32_t))
 
 SDataRow tdSDataRowDup(SDataRow rdata);
-void tdSDataRowCpy(SDataRow src, void *dst);
-void tdFreeSDataRow(SDataRow rdata);
+void     tdSDataRowCpy(SDataRow src, void *dst);
+void     tdFreeSDataRow(SDataRow rdata);
 
 // ---- operation on SDataRows
 #define TD_DATAROWS_LEN(pDataRows) (*(int32_t *)(pDataRows))
@@ -91,18 +103,12 @@ void tdFreeSDataRow(SDataRow rdata);
 #define TD_DATACOLS_NPOINTS(pDataCols) (*(int32_t *)(pDataCols + sizeof(int32_t)))
 
 // ---- operation on SDataRowIter
-int32_t tdInitSDataRowsIter(SDataRows rows, SDataRowsIter *pIter);
+void    tdInitSDataRowsIter(SDataRows rows, SDataRowsIter *pIter);
 int32_t tdRdataIterEnd(SDataRowsIter *pIter);
 void    tdRdataIterNext(SDataRowsIter *pIter);
 
-// ----
-/**
- * Get the maximum
- */
-int32_t tdGetMaxDataRowSize(SSchema *pSchema);
-
 #ifdef __cplusplus
 }
 #endif
 
-#endif // _TD_DATA_FORMAT_H_
+#endif  // _TD_DATA_FORMAT_H_
diff --git a/src/vnode/common/inc/key.h b/src/vnode/common/inc/key.h
deleted file mode 100644
index 1f0478bda3..0000000000
--- a/src/vnode/common/inc/key.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#if !defined(_TD_KEY_H_)
-#define _TD_KEY_H_
-
-typedef struct {
-
-} key;
-
-
-
-#endif // _TD_KEY_H_
diff --git a/src/vnode/common/inc/list.h b/src/vnode/common/inc/list.h
deleted file mode 100644
index 489e39442b..0000000000
--- a/src/vnode/common/inc/list.h
+++ /dev/null
@@ -1,20 +0,0 @@
-#if !defined(_TD_LIST_H_)
-#define _TD_LIST_H_
-
-#include <stdint.h>
-
-typedef enum { TD_LIST_ORDERED, TD_LIST_UNORDERED } TLIST_TYPE;
-
-typedef int32_t (* comparefn(void *key1, void *key2));
-
-struct _list_type {
-    TLIST_TYPE type;
-};
-
-typedef struct _list_node {
-} SListNode;
-
-typedef struct _list {
-} SList;
-
-#endif  // _TD_LIST_H_
diff --git a/src/vnode/common/src/dataformat.c b/src/vnode/common/src/dataformat.c
index 1e4d083f43..3f4b9b6e42 100644
--- a/src/vnode/common/src/dataformat.c
+++ b/src/vnode/common/src/dataformat.c
@@ -2,7 +2,82 @@
 
 #include "dataformat.h"
 
-int32_t tdGetMaxDataRowSize(SSchema *pSchema) {
+static int32_t tdGetMaxDataRowSize(SSchema *pSchema);
+
+/**
+ * Create a data row with maximum row length bytes.
+ *
+ * NOTE: THE AAPLICATION SHOULD MAKE SURE BYTES IS LARGE ENOUGH TO
+ * HOLD THE WHOE ROW.
+ *
+ * @param bytes max bytes a row can take
+ * @return SDataRow object for success
+ *         NULL for failure
+ */
+SDataRow tdNewDataRow(int32_t bytes) {
+  int32_t size = sizeof(int32_t) + bytes;
+
+  SDataRow row = malloc(size);
+  if (row == NULL) return NULL;
+
+  dataRowSetLen(row, sizeof(int32_t));
+
+  return row;
+}
+
+SDataRow tdNewDdataFromSchema(SSchema *pSchema) {
+  int32_t bytes = tdGetMaxDataRowSize(pSchema);
+  return tdNewDataRow(bytes);
+}
+
+/**
+ * Free the SDataRow object
+ */
+void tdFreeDataRow(SDataRow row) {
+  if (row) free(row);
+}
+
+/**
+ * Append a column value to a SDataRow object.
+ * NOTE: THE APPLICATION SHOULD MAKE SURE VALID PARAMETERS. THE FUNCTION ASSUMES
+ * THE ROW OBJECT HAS ENOUGH SPACE TO HOLD THE VALUE.
+ *
+ * @param row the row to append value to
+ * @param value value pointer to append
+ * @param pSchema schema
+ * @param colIdx column index
+ * 
+ * @return 0 for success and -1 for failure
+ */
+int32_t tdAppendColVal(SDataRow row, void *value, SColumn *pCol, int32_t suffixOffset) {
+  int32_t offset;
+
+  switch (pCol->type) {
+    case TD_DATATYPE_BOOL:
+    case TD_DATATYPE_TINYINT:
+    case TD_DATATYPE_SMALLINT:
+    case TD_DATATYPE_INT:
+    case TD_DATATYPE_BIGINT:
+    case TD_DATATYPE_FLOAT:
+    case TD_DATATYPE_DOUBLE:
+      memcpy(dataRowIdx(row, pCol->offset + sizeof(int32_t)), value, rowDataLen[pCol->type]);
+      if (dataRowLen(row) > suffixOffset + sizeof(int32_t))
+        dataRowSetLen(row, dataRowLen(row) + rowDataLen[pCol->type]);
+      break;
+    case TD_DATATYPE_VARCHAR:
+      offset = dataRowLen(row) > suffixOffset ? dataRowLen(row) : suffixOffset;
+      memcpy(dataRowIdx(row, pCol->offset+sizeof(int32_t)), (void *)(&offset), sizeof(offset));
+    case TD_DATATYPE_NCHAR:
+    case TD_DATATYPE_BINARY:
+      break;
+    default:
+      return -1;
+  }
+
+  return 0;
+}
+
+static int32_t tdGetMaxDataRowSize(SSchema *pSchema) {
   int32_t nbytes = 0;
 
   for (int32_t i = 0; i < TD_SCHEMA_NCOLS(pSchema); i++) {
@@ -37,7 +112,7 @@ void     tdFreeSDataRow(SDataRow rdata) {
   free(rdata);
 }
 
-int32_t tdInitSDataRowsIter(SDataRows rows, SDataRowsIter *pIter) {
+void tdInitSDataRowsIter(SDataRows rows, SDataRowsIter *pIter) {
   pIter->totalRows = TD_DATAROWS_ROWS(rows);
   pIter->rowCounter = 1;
   pIter->row = TD_DATAROWS_DATA(rows);
@@ -48,10 +123,7 @@ void tdRdataIterNext(SDataRowsIter *pIter) {
   pIter->row = pIter->row + TD_DATAROW_LEN(pIter->row);
 }
 
-int32_t tdRdataIterEnd(SDataRowsIter *pIter) {
-  return pIter->rowCounter >= pIter->totalRows;
-
-}
+int32_t tdRdataIterEnd(SDataRowsIter *pIter) { return pIter->rowCounter >= pIter->totalRows; }
 
 /**
  * Copy it