diff --git a/visualdl/logic/CMakeLists.txt b/visualdl/logic/CMakeLists.txt
index f1a4250dc342caa116e32c6e54c7da99150cc75f..046e40489b714dcdc881ab06145c933eaf97e989 100644
--- a/visualdl/logic/CMakeLists.txt
+++ b/visualdl/logic/CMakeLists.txt
@@ -1,6 +1,8 @@
 #add_library(sdk ${PROJECT_SOURCE_DIR}/visualdl/logic/sdk.cc)
 add_library(im ${PROJECT_SOURCE_DIR}/visualdl/logic/im.cc)
+add_library(sdk ${PROJECT_SOURCE_DIR}/visualdl/logic/sdk.cc)
 add_dependencies(im storage_proto)
+add_dependencies(sdk storage_proto)
 #add_dependencies(sdk storage_proto)
 
 ## pybind
diff --git a/visualdl/logic/sdk.cc b/visualdl/logic/sdk.cc
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..8ac545813825734251c786d8e853f327c6ff1dc4 100644
--- a/visualdl/logic/sdk.cc
+++ b/visualdl/logic/sdk.cc
@@ -0,0 +1,59 @@
+#include "visualdl/logic/sdk.h"
+
+namespace visualdl {
+
+namespace  components {
+
+template <typename T>
+void components::Scalar<T>::AddRecord(int id, const std::vector<T> &values) {
+  // add record data
+  auto record = tablet_.AddRecord();
+  auto entry = record.AddData<T>();
+  for (auto v : values) {
+    entry.Add(v);
+  }
+  // set record id
+  record.SetId(id);
+  // set record timestamp
+  record.SetTimeStamp(time(NULL));
+}
+
+template <typename T>
+std::vector<T> ScalarReader<T>::records() const {
+  std::vector<T> res;
+  for (int i = 0; i < reader_.total_records(); i++) {
+    res.push_back(reader_.record(i).data<T>(0));
+  }
+  return res;
+}
+
+template <typename T>
+std::vector<int> ScalarReader<T>::ids() const {
+  std::vector<int> res;
+  for (int i = 0; i < reader_.total_records(); i++) {
+    res.push_back(reader_.record(i).id());
+  }
+  return res;
+}
+
+template <typename T>
+std::vector<int> ScalarReader<T>::timestamps() const {
+  std::vector<T> res;
+  for (int i = 0; i < reader_.total_records(); i++) {
+    res.push_back(reader_.record(i).timestamp());
+  }
+  return res;
+}
+
+template <typename T>
+std::vector<std::string> ScalarReader<T>::captions() const {
+  return reader_.captions();
+}
+
+template <typename T>
+size_t ScalarReader<T>::size() const {
+  return reader_.total_records();
+}
+}  // namespace components
+
+}  // namespace visualdl
diff --git a/visualdl/logic/sdk.h b/visualdl/logic/sdk.h
index b3c12f915b1f59144126dc8cbcdf9773a0d4ece2..930fc24ede8bf9837679351bb00e0871fed18aca 100644
--- a/visualdl/logic/sdk.h
+++ b/visualdl/logic/sdk.h
@@ -11,17 +11,32 @@ namespace components {
  * Read and write support for Scalar component.
  */
 template <typename T>
-class Scalar {
-public:
-  Scalar(Tablet tablet) : tablet_(tablet) { tablet_->SetTag(kScalar); }
+struct Scalar {
+  Scalar(Tablet tablet) : tablet_(tablet) { tablet_.SetType(Tablet::Type::kScalar);}
   void SetCaption(const std::string cap) {
-    tablet_->SetCaptions(std::vector<std::string>({cap}));
+    tablet_.SetCaptions(std::vector<std::string>({cap}));
   }
 
+  void AddRecord(int id, const std::vector<T> &values);
+
 private:
   Tablet tablet_;
 };
 
+template <typename T>
+struct ScalarReader {
+  ScalarReader(TabletReader&& reader) : reader_(reader) {}
+
+  std::vector<T> records() const;
+  std::vector<int> ids() const;
+  std::vector<int> timestamps() const;
+  std::vector<std::string> captions() const;
+  size_t size() const;
+
+ private:
+  TabletReader reader_;
+};
+
 }  // namespace components
 }  // namespace visualdl
 
diff --git a/visualdl/storage/storage_test.cc b/visualdl/storage/storage_test.cc
index 9eebdc41d5f44618bfb30bc02caa57b792eef178..8603bf3c0b1bba92d9abb9faba2ff35eecb4c595 100644
--- a/visualdl/storage/storage_test.cc
+++ b/visualdl/storage/storage_test.cc
@@ -21,7 +21,6 @@ TEST_F(StorageTest, main) {
   auto tag0 = storage.AddTablet("tag0");
   auto tag1 = storage.AddTablet("tag1");
 
-
   StorageReader reader("./tmp/storage_test");
   auto modes = reader.Modes();