diff --git a/backend/include/database.h b/backend/include/database.h
index 08107c6..1747354 100644
--- a/backend/include/database.h
+++ b/backend/include/database.h
@@ -15,6 +15,11 @@ class UserDataBase {
   UserDataBase() = default;
   void Open(std::string file_name);
   bool PAM(const std::string &user_id, const std::string &password);
+  int GetPrevilege(const std::string &user_id);
+  void AddUser(const std::string &user_id, const std::string &password,
+               const std::string &user_name, int privilege);
+  void DeleteUser(const std::string &user_id);
+  void ChangePassword(const std::string &user_id, const std::string &password);
 };
 class BookDataBase {
   DriveArray<BookItemClass> full_book_data;
@@ -22,6 +27,12 @@ class BookDataBase {
 
  public:
   void Open(std::string file_name);
+  void QueryBook(const std::string &ISBN, const std::string &name,
+                 const std::string &author, const std::string &keyword,
+                 std::vector<BookItemClass> &ret);
+  void ModifyInfo(const std::string &ISBN, const std::string &name,
+                  const std::string &author, const std::string &keyword,
+                  double price);
 };
 class LogDataBase {
   DriveArray<FinanceItemClass> finance_data;
@@ -29,6 +40,7 @@ class LogDataBase {
 
  public:
   void Open(std::string file_name);
+  void QueryFinance(int count, std::vector<FinanceItemClass> &ret);
 };
 
 #endif  // PROTECTOR_DATABASE_HPP
\ No newline at end of file
diff --git a/backend/src/engine.cpp b/backend/src/engine.cpp
index f5c41bf..7895537 100644
--- a/backend/src/engine.cpp
+++ b/backend/src/engine.cpp
@@ -16,7 +16,8 @@ BookStoreEngineClass::BookStoreEngineClass(std::string __config_dir,
   is_server = __is_server;
 }
 std::vector<std::string> BookStoreEngineClass::Execute(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   for (int i = 0; i < cmd.length(); i++)
     if (std::isspace(cmd[i]) && cmd[i] != ' ')
       return std::vector<std::string>({"Invalid"});
@@ -87,11 +88,9 @@ std::vector<std::string> BookStoreEngineClass::Execute(
       return ExecuteBuy(cmd, login_stack);
     }
     case OperationType::__Kreport: {
-      // throw FatalError("report Not implemented", 2);
       return ExecuteReport(cmd, login_stack);
     }
     case OperationType::__Klog: {
-      // throw FatalError("log Not implemented", 3);
       return ExecuteLog(cmd, login_stack);
     }
   }
@@ -100,71 +99,88 @@ std::vector<std::string> BookStoreEngineClass::Execute(
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteSu(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
+  std::string user_id, password;
+  if (!CommandSuLexer(cmd, user_id, password))
+    return std::vector<std::string>({"Invalid"});
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteLogout(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteRegister(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecutePasswd(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteUserAdd(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteDelete(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteShow(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteBuy(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteSelect(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteMOdify(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteImport(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteShowFinance(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteLog(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
 
 std::vector<std::string> BookStoreEngineClass::ExecuteReport(
-    const std::string &cmd, std::stack<std::pair<std::string, std::string>> &login_stack) {
+    const std::string &cmd,
+    std::stack<std::pair<std::string, std::string>> &login_stack) {
   return std::vector<std::string>();
 }
\ No newline at end of file
diff --git a/backend/src/lexer.cpp b/backend/src/lexer.cpp
index 8f0d7c8..918f14d 100644
--- a/backend/src/lexer.cpp
+++ b/backend/src/lexer.cpp
@@ -156,6 +156,8 @@ bool CommandUseraddLexer(const std::string &command, std::string &user_id,
     ss >> password;
     ss >> privilege;
     ss >> username;
+    if (privilege != 0 && privilege != 1 && privilege != 3 && privilege != 7)
+      return false;
     return true;
   } else
     return false;