diff --git a/src/vnode/common/inc/schema.h b/src/vnode/common/inc/schema.h
index 62b642894e3b89edba4d7160135d64e7f298eace..c8ac6e7f6740043b31c44907e98665894a315c34 100644
--- a/src/vnode/common/inc/schema.h
+++ b/src/vnode/common/inc/schema.h
@@ -3,40 +3,54 @@
 
 #include <stdint.h>
 
-#include "tstring.h"
 #include "type.h"
 
-typedef struct _scolumn {
-  tstring_t colName;      // column name
-  td_datatype_t type;     // data type
-  int32_t bytes;          // number of bytes
+// Column definition
+// TODO: if we need to align the structure
+typedef struct {
+  td_datatype_t type;     // Column type
+  int32_t       colId;    // column ID
+  int32_t       bytes;    // column bytes
+  char *        colName;  // the column name
 } SColumn;
 
-typedef struct SSchema {
-  int32_t numOfCols;
+// Schema definition
+typedef struct {
+  int32_t  version;  // schema version, it is used to change the schema
+  int32_t  numOfCols;
+  int32_t  numOfTags;
+  int32_t  colIdCounter;
   SColumn *columns;
 } SSchema;
 
-// Column with version
-typedef struct {
-  tstring_t colName;
-  td_datatype_t type;
-  int32_t colId;
-  int32_t bytes;
-} SVColumn;
-
-// Schema with version
-typedef struct {
-  int32_t version;      // Schema with version
-  int32_t numOfCols;
-  int32_t numOfTags;
-  SVColumn *columns;
-} SVSchema;
-
-int32_t tdAddColumnToSchema(tstring_t pSchema, SColumn col);
-
-td_datatype_t tdGetTypeOfCol(SSchema *pSchema, int32_t col);
-int32_t tdGetLengthOfCol(SSchema *pSchema, int32_t col);
-
+/* Inline schema definition
+ * +---------+---------+---------+-----+---------+-----------+-----+-----------+
+ * | int32_t |         |         |     |         |           |     |           |
+ * +---------+---------+---------+-----+---------+-----------+-----+-----------+
+ * |   len   | SSchema | SColumn | ... | SColumn | col1_name | ... | colN_name |
+ * +---------+---------+---------+-----+---------+-----------+-----+-----------+
+ */
+typedef char *SISchema
+
+// ---- operation on SColumn
+#define TD_COLUMN_TYPE(pCol) ((pCol)->type)
+#define TD_COLUMN_ID(pCol) ((pCol)->colId)
+#define TD_COLUMN_BYTES(pCol) ((pCol)->bytes)
+#define TD_COLUMN_NAME(pCol) ((pCol)->colName)
+
+// ---- operation on SSchema
+#define TD_SCHEMA_VERSION(pSchema) ((pSchema)->version)
+#define TD_SCHEMA_NCOLS(pSchema) ((pSchema)->numOfCols)
+#define TD_SCHEMA_NTAGS(pSchema) ((pSchema)->numOfTags)
+#define TD_SCHEMA_TOTAL_COLS(pSchema) (TD_SCHEMA_NCOLS(pSchema) + TD_SCHEMA_NTAGS(pSchema))
+#define TD_SCHEMA_NEXT_COLID(pSchema) ((pSchema)->colIdCounter++)
+#define TD_SCHEMA_COLS(pSchema) ((pSchema)->columns)
+#define TD_SCHEMA_TAGS(pSchema) (TD_SCHEMA_COLS(pSchema) + TD_SCHEMA_NCOLS(pSchema))
+#define TD_SCHEMA_COLUMN_AT(pSchema, idx) TD_SCHEMA_COLS(pSchema)[idx]
+#define TD_SCHEMA_TAG_AT(pSchema, idx) TD_SCHEMA_TAGS(pSchema)[idx]
+
+// ---- operation on SISchema
+#define TD_ISCHEMA_LEN(pISchema) *((int32_t *)(pISchema))
+#define TD_ISCHEMA_SCHEMA(pISchema) ((SSchema *)((pISchema) + sizeof(int32_t)))
 
 #endif  // _TD_SCHEMA_H_
diff --git a/src/vnode/common/inc/type.h b/src/vnode/common/inc/type.h
index c36d7fd43aecc1ec18d12f1bcd43ba3e20ece05f..c7cf10c52c3456b44696341a09222eda27a61d5e 100644
--- a/src/vnode/common/inc/type.h
+++ b/src/vnode/common/inc/type.h
@@ -29,4 +29,6 @@ typedef enum : uint8_t {
 #define TD_DATATYPE_NCHAR_NULL
 #define TD_DATATYPE_BINARY_NULL
 
+#define TD_IS_VALID_DATATYPE(type) (((type) > TD_DATA_TYPE_INVLD) && ((type) <= TD_DATATYPE_BINARY))
+
 #endif // _TD_TYPE_H_