diff --git a/editbooktype.cpp b/editbooktype.cpp
index e69de29..b64d135 100644
--- a/editbooktype.cpp
+++ b/editbooktype.cpp
@@ -0,0 +1,175 @@
+#include "Session.h"
+#include "Util.h"
+#include "json.hpp"
+#include "jsonfail.h"
+using namespace std;
+using json=nlohmann::json;
+
+#define postval(NAME) string NAME=req.post[#NAME]
+
+int main()
+{
+    Request req;
+    Session se(req);
+    Response res;
+    json j;
+
+    auto jsonfail=[&](int errcode,const string& detail="")
+    {
+        j["success"]=0;
+        j["errcode"]=errcode;
+        j["errmsg"]=string(GetErrMsg(errcode))+" : "+detail;
+    };
+
+    do
+    {
+        if(!se.isReady()||se.isNew()||se.getUser().empty())
+        {
+            jsonfail(err_need_login);
+            break;
+        }
+
+        if(req.requestMethod!="POST")
+        {
+            jsonfail(err_method_not_supported);
+            break;
+        }
+
+        if(req.post["booktype_old"].empty() ||
+           req.post["booktype_new"].empty())
+        {
+            jsonfail(err_missing_parameter);
+            break;
+        }
+
+        postval(booktype_old);
+        postval(booktype_new);
+
+        DBInfo db;
+        MySQLConn conn;
+        if(db.readConfig()<0)
+        {
+            jsonfail(err_config);
+            break;
+        }
+
+        if(db.connectProxy(conn)<0)
+        {
+            jsonfail(err_connect);
+            break;
+        }
+
+        /// Check Permission
+        int permission_level;
+        if(conn.exec(make_str("select permission_level from bs_user where username='",
+                              se.getUser(),
+                              "'"),
+                     [&](MySQLResult& res)
+                     {
+                         res.stepRow([&](char** val,unsigned long* len)
+                                     {
+                                         permission_level=ParseInt(val[0]);
+                                    });
+                    })<0)
+        {
+            jsonfail(err_sql,"Step 1");
+            break;
+        }
+
+        if(permission_level>1)
+        {
+            /// Permission Denied.
+            jsonfail(err_permission_denied);
+            break;
+        }
+
+        int count_old;
+        if(conn.exec(make_str("select count(book_type) from bs_booktype where book_type='",
+                              booktype_old,
+                              "'"),
+                     [&](MySQLResult& res)
+                     {
+                         res.stepRow([&](char** val,unsigned long* len)
+                                     {
+                                         count_old=ParseInt(val[0]);
+                                     });
+                     })<0)
+        {
+            jsonfail(err_sql,"Step 2");
+            break;
+        }
+
+        if(count_old!=1)
+        {
+            jsonfail(err_data,"old value incorrect");
+            break;
+        }
+
+        int count_new;
+        if(conn.exec(make_str("select count(book_type) from bs_booktype where booktype='",
+                              booktype_new,
+                              "'"),
+                     [&](MySQLResult& res)
+                     {
+                         res.stepRow([&](char** val,unsigned long* len)
+                                     {
+                                         count_new=ParseInt(val[0]);
+                                     });
+                     })<0)
+        {
+            jsonfail(err_sql,"Step 3");
+            break;
+        }
+
+        if(count_new!=0)
+        {
+            jsonfail(err_data,"new value conflict");
+            break;
+        }
+
+        int count_old_ref;
+        if(conn.exec(make_str("select count(book_type) from bs_book where book_type='",
+                              booktype_old,
+                              "'"),
+                     [&](MySQLResult& res)
+                     {
+                         res.stepRow([&](char** val,unsigned long* len)
+                                     {
+                                         count_old_ref=ParseInt(val[0]);
+                                     });
+                     })<0)
+        {
+            jsonfail(err_sql,"Step 4");
+            break;
+        }
+
+        if(count_old_ref!=0)
+        {
+            jsonfail(err_data,"old value reference count not equals 0");
+            break;
+        }
+
+        /// do update
+        if(conn.exec(make_str("update bs_booktype set book_type='",
+                              booktype_new,
+                              "' where book_type='",
+                              booktype_old,
+                              "'"),nullptr)<0)
+        {
+            jsonfail(err_sql,"Step 5");
+            break;
+        }
+
+        if(conn.getAffectedRows()!=1)
+        {
+            jsonfail(err_sql_logic,"Affected rows not equals 1");
+            break;
+        }
+
+
+    }while(0);
+
+    res.content.append(j.dump());
+    res.show();
+    return 0;
+}