diff --git a/examples/object/README.md b/examples/object/README.md
index faaa719..1c82fdb 100644
--- a/examples/object/README.md
+++ b/examples/object/README.md
@@ -28,10 +28,12 @@ mysql> select * from monitors_with_tag;
 +------+-----------+--------+------+-------------+---------+----------------------------+
 | id   | host      | memory | cpu  | temperature | running | ts                         |
 +------+-----------+--------+------+-------------+---------+----------------------------+
-|    1 | 127.0.0.1 |      1 |  1.1 |          -1 |       1 | 2024-03-23 14:36:06.591000 |
-|    1 | 127.0.0.1 |      1 |  1.1 |          -1 |       1 | 2024-03-23 14:36:06.732000 |
-|    2 | 127.0.0.2 |      2 |    2 |          -2 |       1 | 2024-03-23 14:36:06.591000 |
-|    2 | 127.0.0.2 |      2 |    2 |          -2 |       1 | 2024-03-23 14:36:06.732000 |
+|    0 | 127.0.0.1 |      1 |  1.3 |          -1 |       0 | 2024-08-14 09:20:04.475000 |
+|    0 | 127.0.0.1 |      1 |  1.3 |          -1 |       0 | 2024-08-14 09:20:04.664000 |
+|    1 | 127.0.0.2 |      1 |  1.1 |          -1 |       1 | 2024-08-14 09:20:04.475000 |
+|    1 | 127.0.0.2 |      1 |  1.1 |          -1 |       1 | 2024-08-14 09:20:04.664000 |
+|    2 | 127.0.0.3 |      2 |    2 |          -2 |       1 | 2024-08-14 09:20:04.475000 |
+|    2 | 127.0.0.3 |      2 |    2 |          -2 |       1 | 2024-08-14 09:20:04.664000 |
 +------+-----------+--------+------+-------------+---------+----------------------------+
-4 rows in set (0.12 sec)
+6 rows in set (0.03 sec)
 ```
diff --git a/examples/object/main.go b/examples/object/main.go
index f25dc70..0f6b0d8 100644
--- a/examples/object/main.go
+++ b/examples/object/main.go
@@ -53,9 +53,16 @@ func (Monitor) TableName() string {
 func initData() []Monitor {
 	return []Monitor{
 		{
-			ID:          1,
 			Host:        "127.0.0.1",
 			Memory:      1,
+			Cpu:         1.3,
+			Temperature: -1,
+			Ts:          time.Now(),
+		},
+		{
+			ID:          1,
+			Host:        "127.0.0.2",
+			Memory:      1,
 			Cpu:         1.0,
 			Temperature: -1,
 			Ts:          time.Now(),
@@ -63,7 +70,7 @@ func initData() []Monitor {
 		},
 		{
 			ID:          2,
-			Host:        "127.0.0.2",
+			Host:        "127.0.0.3",
 			Memory:      2,
 			Cpu:         2.0,
 			Temperature: -2,
@@ -72,7 +79,7 @@ func initData() []Monitor {
 		},
 		{
 			ID:          3,
-			Host:        "127.0.0.3",
+			Host:        "127.0.0.4",
 			Memory:      3,
 			Cpu:         3.0,
 			Temperature: -3,
@@ -81,6 +88,7 @@ func initData() []Monitor {
 		},
 	}
 }
+
 func writeObject(data []Monitor) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
 	defer cancel()
@@ -136,19 +144,19 @@ func main() {
 	// insert
 	writeObject(data)
 	// update
-	data[0].Cpu = 1.1
+	data[1].Cpu = 1.1
 	writeObject(data)
 	// delete
-	deleteObject(data[2:])
+	deleteObject(data[3:])
 
 	time.Sleep(time.Millisecond * 100)
 
 	data = initData()
 	// stream insert
 	streamWriteObject(data)
-	data[0].Cpu = 1.1
+	data[1].Cpu = 1.1
 	// stream update
 	streamWriteObject(data)
 	// stream delete
-	streamDeleteObject(data[2:])
+	streamDeleteObject(data[3:])
 }
diff --git a/request/request.go b/request/request.go
index d46366d..686b676 100644
--- a/request/request.go
+++ b/request/request.go
@@ -51,12 +51,12 @@ func (r *Request) WithTables(tables ...*table.Table) *Request {
 	return r
 }
 
-func (r *Request) IsZero() bool {
-	return r.tables == nil || len(r.tables) == 0
+func (r *Request) IsNilTable() bool {
+	return r.tables == nil
 }
 
 func (r *Request) Build() (*gpb.GreptimeRequest, error) {
-	if r.IsZero() {
+	if r.IsNilTable() {
 		return nil, errs.ErrEmptyTable
 	}
 
diff --git a/schema/field.go b/schema/field.go
index d8c2579..5fbb9c4 100644
--- a/schema/field.go
+++ b/schema/field.go
@@ -180,7 +180,7 @@ func parseIntOrTimeValue(typ gpb.ColumnDataType, val reflect.Value) (*gpb.Value,
 
 func parseValue(typ gpb.ColumnDataType, val reflect.Value) (*gpb.Value, error) {
 	val = reflect.Indirect(val)
-	if !val.IsValid() || val.IsZero() {
+	if !val.IsValid() {
 		return nil, nil
 	}