diff --git a/memdb/include/memdb.hpp b/memdb/include/memdb.hpp
new file mode 100644
index 0000000..8985a60
--- /dev/null
+++ b/memdb/include/memdb.hpp
@@ -0,0 +1,60 @@
+#pragma once
+#include <memory>
+#include <list>
+#include <unordered_map>
+#include <chrono>
+#include <queue>
+
+
+
+template <typename T, typename U>
+
+class Memdb {
+
+
+struct memdb_column {
+    T key;
+    U value;
+    std::chrono::system_clock::time_point timestamp;
+    bool be_del = false;
+};
+
+struct index_keys {
+    T key;
+    std::list <memdb_column>::iterator item;
+};
+
+struct index_timestamp {
+    std::list <memdb_column>::iterator item;
+
+    bool operator<(const index_timestamp& a) const;
+};
+
+
+private:
+    std::list <memdb_column> db;
+    std::unordered_map <T, index_keys> keys;
+    std::priority_queue <index_timestamp> time_touch;
+    size_t __size;
+    void flush();
+
+
+public:
+    using key_t = T;
+    using value_t = U;
+    static constexpr int npos = -1;
+
+    Memdb();
+    Memdb& operator=(const Memdb& to_be_cp_memdb);
+    ~Memdb();
+
+    size_t size() const;
+    const std::unordered_map <T, index_keys>& get_keys() const;
+    const std::list <memdb_column>& get_db() const;
+    const std::priority_queue <index_timestamp>& get_time_touch() const;
+
+    void insert(key_t to_be_ins_k, value_t ins_v);                                  //TODO 要加返回值
+    void remove(key_t to_be_del_k);                                                 //TODO 要加返回值
+    void update(key_t to_be_udt_k, value_t udt_v, bool need_to_udt_timetouch=false);//TODO 要加返回值
+    value_t search(key_t to_be_sch_k) const;
+};
\ No newline at end of file
diff --git a/memdb/src/main.cpp b/memdb/src/main.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/memdb/src/main/memdb.cpp b/memdb/src/main/memdb.cpp
new file mode 100644
index 0000000..9209ec6
--- /dev/null
+++ b/memdb/src/main/memdb.cpp
@@ -0,0 +1,126 @@
+#include "memdb.hpp"
+
+
+
+template <typename T, typename U>
+
+bool Memdb <T, U>::index_timestamp::operator<(const index_timestamp& a) const {
+    return this -> item -> timestamp > a.item -> timestamp;
+}
+
+
+template <typename T, typename U>
+
+void Memdb <T, U>::flush() {
+    std::chrono::system_clock::time_point now_time = std::chrono::system_clock::now();
+    std::list <memdb_column>::iterator it = this -> time_touch.front().item;
+
+    while (now_time > it -> timestamp || it -> be_del == true) {
+        this -> keys.erase(it -> key);
+        this -> db.erase(it);
+		this -> time_touch.pop();
+		this -> __size--;
+        it = this -> time_touch.front().item;
+        now_time = std::chrono::system_clock::now();
+    }
+}
+
+template <typename T, typename U>
+
+Memdb <T, U>::Memdb() = default;
+
+
+template <typename T, typename U>
+
+Memdb <T, U>& Memdb <T, U>::operator=(const Memdb <T, U>& to_be_cp_memdb) = default;
+
+
+template <typename T, typename U>
+
+Memdb <T, U>::~Memdb() = default;
+
+
+template <typename T, typename U>
+
+size_t Memdb <T, U>::size() const {
+    return this -> __size;
+}
+
+
+template <typename T, typename U>
+
+const std::unordered_map <T, typename Memdb <T, U>::index_keys>& Memdb <T, U>::get_keys() const {
+    return this -> keys;
+}
+
+
+template <typename T, typename U>
+
+const std::list <typename Memdb <T, U>::memdb_column>& Memdb <T, U>::get_db() const {
+    return this -> db;
+}
+
+
+template <typename T, typename U>
+
+const std::priority_queue <typename Memdb <T, U>::index_timestamp>& Memdb <T, U>::get_time_touch() const {
+    return this -> time_touch;
+}
+
+
+template <typename T, typename U>
+
+void Memdb <T, U>::insert(key_t to_be_ins_k, value_t ins_v) {
+    this -> flush();
+
+    std::chrono::system_clock::time_point now_time = std::chrono::system_clock::now();
+
+    Memdb::memdb_column new_column;
+    new_column.key = to_be_ins_k;
+    new_column.value = ins_v;
+    new_column.timestamp = now_time;
+    this -> db.push_back(new_column);
+
+    Memdb::index_keys new_key;
+    new_key.key = to_be_ins_k;
+    new_key.item = std::prev(this -> db.end());
+    this -> keys.insert(new_key);
+
+    Memdb::index_timestamp new_time_touch;
+    new_time_touch.item = std::prev(this -> db.end());
+    this -> time_touch.push(new_time_touch);
+}
+
+
+template <typename T, typename U>
+
+void Memdb <T, U>::remove(key_t to_be_del_k) {
+    this -> flush();
+
+    std::list <memdb_column>::iterator it = this -> keys[to_be_del_k].item;
+    it -> be_del = true;
+}
+
+
+template <typename T, typename U>
+
+void Memdb <T, U>::update(key_t to_be_udt_k, value_t udt_v, bool need_to_udt_timetouch=false) {
+    this -> flush();
+
+    std::list <memdb_column>::iterator it = this -> keys[to_be_udt_k];  //! 这边会默认插入
+    it -> value = udt_v;
+    if (need_to_udt_timetouch == true) {
+        std::chrono::system_clock::time_point now_time = std::chrono::system_clock::now();
+        it -> timestamp = now_time;
+    }
+}
+
+
+template <typename T, typename U>
+
+Memdb <T, U>::value_t Memdb <T, U>::search(key_t to_be_sch_k) const {
+    this -> flush();
+
+    std::list <memdb_column>::iterator it = this -> keys[to_be_sch_k];  //! 这边会默认插入
+    return it -> value;
+}