22 files changed, 46 insertions, 415 deletions
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index dfb909a..432248b 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,8 +1,6 @@
 Version 8.0
 ===========
 
-- Changed the data type used to store the dates in the database. This
-  requires an automatic migration on the first start.
 - Add a complete='true' in MAM’s iq result when appropriate
 - The “virtual” channel with an empty name (for example
   %irc.freenode.net@biboumi) has been entirely removed.
diff --git a/src/bridge/bridge.cpp b/src/bridge/bridge.cpp
index defb9a5..1c646fe 100644
--- a/src/bridge/bridge.cpp
+++ b/src/bridge/bridge.cpp
@@ -1009,9 +1009,9 @@ void Bridge::send_room_history(const std::string& hostname, std::string chan_nam
   chan_name.append(utils::empty_if_fixed_server("%" + hostname));
   for (const auto& line: lines)
     {
-      const DateTime& datetime = line.col<Database::Date>();
+      const auto seconds = line.col<Database::Date>();
       this->xmpp.send_history_message(chan_name, line.col<Database::Nick>(), line.col<Database::Body>(),
-                                      this->user_jid + "/" + resource, datetime);
+                                      this->user_jid + "/" + resource, seconds);
     }
 #else
   (void)hostname;
diff --git a/src/database/database.cpp b/src/database/database.cpp
index c935139..a09dfe3 100644
--- a/src/database/database.cpp
+++ b/src/database/database.cpp
@@ -48,7 +48,6 @@ void Database::open(const std::string& filename)
   Database::db = std::move(new_db);
   Database::muc_log_lines.create(*Database::db);
   Database::muc_log_lines.upgrade(*Database::db);
-  convert_date_format(*Database::db, Database::muc_log_lines);
   Database::global_options.create(*Database::db);
   Database::global_options.upgrade(*Database::db);
   Database::irc_server_options.create(*Database::db);
@@ -60,9 +59,9 @@ void Database::open(const std::string& filename)
   Database::after_connection_commands.create(*Database::db);
   Database::after_connection_commands.upgrade(*Database::db);
   create_index<Database::Owner, Database::IrcChanName, Database::IrcServerName>(*Database::db, "archive_index", Database::muc_log_lines.get_name());
-  Database::db->init_session();
 }
 
+
 Database::GlobalOptions Database::get_global_options(const std::string& owner)
 {
   auto request = select(Database::global_options);
@@ -171,7 +170,7 @@ Database::IrcChannelOptions Database::get_irc_channel_options_with_server_and_gl
 }
 
 std::string Database::store_muc_message(const std::string& owner, const std::string& chan_name,
-                                        const std::string& server_name, DateTime::time_point date,
+                                        const std::string& server_name, Database::time_point date,
                                         const std::string& body, const std::string& nick)
 {
   auto line = Database::muc_log_lines.row();
@@ -182,7 +181,7 @@ std::string Database::store_muc_message(const std::string& owner, const std::str
   line.col<Owner>() = owner;
   line.col<IrcChanName>() = chan_name;
   line.col<IrcServerName>() = server_name;
-  line.col<Date>() = date;
+  line.col<Date>() = std::chrono::duration_cast<std::chrono::seconds>(date.time_since_epoch()).count();
   line.col<Body>() = body;
   line.col<Nick>() = nick;
 
@@ -206,21 +205,13 @@ std::vector<Database::MucLogLine> Database::get_muc_logs(const std::string& owne
     {
       const auto start_time = utils::parse_datetime(start);
       if (start_time != -1)
-        {
-          DateTime datetime(start_time);
-          DatetimeWriter writer(datetime, *Database::db);
-          request << " and " << Database::Date{} << ">=" << writer;
-        }
+        request << " and " << Database::Date{} << ">=" << start_time;
     }
   if (!end.empty())
     {
       const auto end_time = utils::parse_datetime(end);
       if (end_time != -1)
-        {
-          DateTime datetime(end_time);
-          DatetimeWriter writer(datetime, *Database::db);
-          request << " and " << Database::Date{} << "<=" << writer;
-        }
+        request << " and " << Database::Date{} << "<=" << end_time;
     }
   if (reference_record_id != Id::unset_value)
     {
@@ -233,9 +224,9 @@ std::vector<Database::MucLogLine> Database::get_muc_logs(const std::string& owne
     }
 
   if (paging == Database::Paging::first)
-    request.order_by() << Database::Date{} << " ASC";
+    request.order_by() << Database::Date{} << " ASC, " << Id{} << " ASC ";
   else
-    request.order_by() << Database::Date{} << " DESC";
+    request.order_by() << Database::Date{} << " DESC, " << Id{} << " DESC ";
 
   if (limit >= 0)
     request.limit() << limit;
@@ -261,21 +252,13 @@ Database::MucLogLine Database::get_muc_log(const std::string& owner, const std::
     {
       const auto start_time = utils::parse_datetime(start);
       if (start_time != -1)
-        {
-          DateTime datetime(start_time);
-          DatetimeWriter writer(datetime, *Database::db);
-          request << " and " << Database::Date{} << ">=" << writer;
-        }
+        request << " and " << Database::Date{} << ">=" << start_time;
     }
   if (!end.empty())
     {
       const auto end_time = utils::parse_datetime(end);
       if (end_time != -1)
-        {
-          DateTime datetime(end_time);
-          DatetimeWriter writer(datetime, *Database::db);
-          request << " and " << Database::Date{} << "<=" << writer;
-        }
+        request << " and " << Database::Date{} << "<=" << end_time;
     }
 
   auto result = request.execute(*Database::db);
@@ -359,12 +342,4 @@ Transaction::~Transaction()
         log_error("Failed to end SQL transaction: ", std::get<std::string>(result));
     }
 }
-
-void Transaction::rollback()
-{
-  this->success = false;
-  const auto result = Database::raw_exec("ROLLBACK");
-  if (std::get<bool>(result) == false)
-    log_error("Failed to rollback SQL transaction: ", std::get<std::string>(result));
-}
 #endif
diff --git a/src/database/database.hpp b/src/database/database.hpp
index 75ff8f3..d986ecc 100644
--- a/src/database/database.hpp
+++ b/src/database/database.hpp
@@ -10,7 +10,6 @@
 #include <database/engine.hpp>
 
 #include <utils/optional_bool.hpp>
-#include <utils/datetime.hpp>
 
 #include <chrono>
 #include <string>
@@ -18,9 +17,11 @@
 #include <memory>
 #include <map>
 
+
 class Database
 {
  public:
+  using time_point = std::chrono::system_clock::time_point;
   struct RecordNotFound: public std::exception {};
   enum class Paging { first, last };
 
@@ -36,8 +37,7 @@ class Database
 
   struct Server: Column<std::string> { static constexpr auto name = "server_"; };
 
-  struct OldDate: Column<std::chrono::system_clock::time_point::rep> { static constexpr auto name = "date_"; };
-  struct Date: Column<DateTime> { static constexpr auto name = "date_"; };
+  struct Date: Column<time_point::rep> { static constexpr auto name = "date_"; };
 
   struct Body: Column<std::string> { static constexpr auto name = "body_"; };
 
@@ -88,8 +88,6 @@ class Database
 
   using MucLogLineTable = Table<Id, Uuid, Owner, IrcChanName, IrcServerName, Date, Body, Nick>;
   using MucLogLine = MucLogLineTable::RowType;
-  using OldMucLogLineTable = Table<Id, Uuid, Owner, IrcChanName, IrcServerName, OldDate, Body, Nick>;
-  using OldMucLogLine = OldMucLogLineTable::RowType;
 
   using GlobalOptionsTable = Table<Id, Owner, MaxHistoryLength, RecordHistory, GlobalPersistent>;
   using GlobalOptions = GlobalOptionsTable::RowType;
@@ -143,7 +141,7 @@ class Database
    */
   static MucLogLine get_muc_log(const std::string& owner, const std::string& chan_name, const std::string& server, const std::string& uuid, const std::string& start="", const std::string& end="");
   static std::string store_muc_message(const std::string& owner, const std::string& chan_name, const std::string& server_name,
-                                       DateTime::time_point date, const std::string& body, const std::string& nick);
+                                       time_point date, const std::string& body, const std::string& nick);
 
   static void add_roster_item(const std::string& local, const std::string& remote);
   static bool has_roster_item(const std::string& local, const std::string& remote);
@@ -170,13 +168,6 @@ class Database
 
   static std::unique_ptr<DatabaseEngine> db;
 
-  static DatabaseEngine::EngineType engine_type()
-  {
-    if (Database::db)
-      return Database::db->engine_type();
-    return DatabaseEngine::EngineType::None;
-  }
-
   /**
    * Some caches, to avoid doing very frequent query requests for a few options.
    */
@@ -225,20 +216,7 @@ class Transaction
 public:
   Transaction();
   ~Transaction();
-  void rollback();
   bool success{false};
 };
 
-template <typename... T>
-void convert_date_format(DatabaseEngine& db, Table<T...> table)
-{
-  const auto existing_columns = db.get_all_columns_from_table(table.get_name());
-  const auto date_pair = existing_columns.find(Database::Date::name);
-  if (date_pair != existing_columns.end() && date_pair->second == "integer")
-    {
-      log_info("Converting Date_ format to the new one.");
-      db.convert_date_format(db);
-    }
-}
-
 #endif /* USE_DATABASE */
diff --git a/src/database/datetime_writer.hpp b/src/database/datetime_writer.hpp
deleted file mode 100644
index b104911..0000000
--- a/src/database/datetime_writer.hpp
+++ /dev/null
@@ -1,32 +0,0 @@
-#pragma once
-
-#include <utils/datetime.hpp>
-#include <database/engine.hpp>
-
-#include <logger/logger.hpp>
-#include <database/postgresql_engine.hpp>
-#include <database/sqlite3_engine.hpp>
-
-class DatetimeWriter
-{
-public:
-  DatetimeWriter(DateTime datetime, const DatabaseEngine& engine):
-      datetime(datetime),
-      engine(engine)
-  {}
-
-  long double get_value() const
-  {
-    const long double epoch_duration = this->datetime.epoch().count();
-    const long double epoch_seconds = epoch_duration / std::chrono::system_clock::period::den;
-    return this->engine.epoch_to_floating_value(epoch_seconds);
-  }
-  std::string escape_param_number(int value) const
-  {
-    return this->engine.escape_param_number(value);
-  }
-
-private:
-  const DateTime datetime;
-  const DatabaseEngine& engine;
-};
diff --git a/src/database/engine.hpp b/src/database/engine.hpp
index ecf047f..41dccf5 100644
--- a/src/database/engine.hpp
+++ b/src/database/engine.hpp
@@ -13,7 +13,6 @@
 #include <string>
 #include <vector>
 #include <tuple>
-#include <map>
 #include <set>
 
 class DatabaseEngine
@@ -28,10 +27,7 @@ class DatabaseEngine
   DatabaseEngine(DatabaseEngine&&) = delete;
   DatabaseEngine& operator=(DatabaseEngine&&) = delete;
 
-  enum class EngineType { None, Postgresql, Sqlite3, };
-  virtual EngineType engine_type() const = 0;
-
-  virtual std::map<std::string, std::string> get_all_columns_from_table(const std::string& table_name) = 0;
+  virtual std::set<std::string> get_all_columns_from_table(const std::string& table_name) = 0;
   virtual std::tuple<bool, std::string> raw_exec(const std::string& query) = 0;
   virtual std::unique_ptr<Statement> prepare(const std::string& query) = 0;
   virtual void extract_last_insert_rowid(Statement& statement) = 0;
@@ -39,17 +35,7 @@ class DatabaseEngine
   {
     return {};
   }
-  virtual void convert_date_format(DatabaseEngine&) = 0;
-  virtual std::string id_column_type() const = 0;
-  virtual std::string datetime_column_type() const = 0;
-  virtual long double epoch_to_floating_value(long double seconds) const = 0;
-  virtual std::string escape_param_number(int nb) const
-  {
-    return "$" + std::to_string(nb);
-  }
-  virtual void init_session()
-  {
-  }
+  virtual std::string id_column_type() = 0;
 
   int64_t last_inserted_rowid{-1};
 };
diff --git a/src/database/insert_query.cpp b/src/database/insert_query.cpp
deleted file mode 100644
index f72d67f..0000000
--- a/src/database/insert_query.cpp
+++ /dev/null
@@ -1,21 +0,0 @@
-#include <database/insert_query.hpp>
-
-template <>
-std::string before_value<Database::Date>()
-{
-  if (Database::engine_type() == DatabaseEngine::EngineType::Sqlite3)
-    return "julianday(";
-  if (Database::engine_type() == DatabaseEngine::EngineType::Postgresql)
-    return "to_timestamp(";
-  return {};
-}
-
-template <>
-std::string after_value<Database::Date>()
-{
-  if (Database::engine_type() == DatabaseEngine::EngineType::Sqlite3)
-    return ", \"unixepoch\")";
-  if (Database::engine_type() == DatabaseEngine::EngineType::Postgresql)
-    return ")";
-  return {};
-}
diff --git a/src/database/insert_query.hpp b/src/database/insert_query.hpp
index cd1942f..230e873 100644
--- a/src/database/insert_query.hpp
+++ b/src/database/insert_query.hpp
@@ -30,24 +30,6 @@ typename std::enable_if<N == sizeof...(T), void>::type
 update_autoincrement_id(std::tuple<T...>&, Statement&)
 {}
 
-template <typename T>
-std::string before_value()
-{
-  return {};
-}
-
-template <typename T>
-std::string after_value()
-{
-  return {};
-}
-
-template <>
-std::string before_value<Database::Date>();
-
-template <>
-std::string after_value<Database::Date>();
-
 struct InsertQuery: public Query
 {
   template <typename... T>
@@ -96,7 +78,7 @@ struct InsertQuery: public Query
   template <typename... T>
   void insert_values(const std::tuple<T...>& columns)
   {
-    this->body += " VALUES (";
+    this->body += "VALUES (";
     this->insert_value(columns);
     this->body += ")";
   }
@@ -109,9 +91,7 @@ struct InsertQuery: public Query
 
     if (!std::is_same<ColumnType, Id>::value)
       {
-        this->body += before_value<ColumnType>();
         this->body += "$" + std::to_string(index++);
-        this->body += after_value<ColumnType>();
         if (N != sizeof...(T) - 1)
           this->body += ", ";
       }
diff --git a/src/database/postgresql_engine.cpp b/src/database/postgresql_engine.cpp
index d97f2ff..59bc885 100644
--- a/src/database/postgresql_engine.cpp
+++ b/src/database/postgresql_engine.cpp
@@ -2,7 +2,6 @@
 #ifdef PQ_FOUND
 
 #include <utils/scopeguard.hpp>
-#include <utils/tolower.hpp>
 
 #include <database/query.hpp>
 
@@ -13,7 +12,6 @@
 #include <logger/logger.hpp>
 
 #include <cstring>
-#include <database/database.hpp>
 
 PostgresqlEngine::PostgresqlEngine(PGconn*const conn):
     conn(conn)
@@ -54,14 +52,14 @@ std::unique_ptr<DatabaseEngine> PostgresqlEngine::open(const std::string& connin
   return std::make_unique<PostgresqlEngine>(con);
 }
 
-std::map<std::string, std::string> PostgresqlEngine::get_all_columns_from_table(const std::string& table_name)
+std::set<std::string> PostgresqlEngine::get_all_columns_from_table(const std::string& table_name)
 {
-  const auto query = "SELECT column_name, data_type from information_schema.columns where table_name='" + table_name + "'";
+  const auto query = "SELECT column_name from information_schema.columns where table_name='" + table_name + "'";
   auto statement = this->prepare(query);
-  std::map<std::string, std::string> columns;
+  std::set<std::string> columns;
 
   while (statement->step() == StepResult::Row)
-    columns[utils::tolower(statement->get_column_text(0))] = utils::tolower(statement->get_column_text(1));
+    columns.insert(statement->get_column_text(0));
 
   return columns;
 }
@@ -98,41 +96,9 @@ std::string PostgresqlEngine::get_returning_id_sql_string(const std::string& col
   return " RETURNING " + col_name;
 }
 
-std::string PostgresqlEngine::id_column_type() const
+std::string PostgresqlEngine::id_column_type()
 {
   return "SERIAL";
 }
 
-std::string PostgresqlEngine::datetime_column_type() const
-{
-  return "TIMESTAMP";
-}
-
-void PostgresqlEngine::convert_date_format(DatabaseEngine& db)
-{
-  const auto table_name = Database::muc_log_lines.get_name();
-  const std::string column_name = Database::Date::name;
-  const std::string query = "ALTER TABLE " + table_name + " ALTER COLMUN " + column_name + " SET DATA TYPE timestamp USING to_timestamp(" + column_name + ")";
-
-  auto result = db.raw_exec(query);
-  if (!std::get<bool>(result))
-    log_error("Failed to execute query: ", std::get<std::string>(result));
-}
-
-std::string PostgresqlEngine::escape_param_number(int nb) const
-{
-  return "to_timestamp(" + DatabaseEngine::escape_param_number(nb) + ")";
-}
-
-void PostgresqlEngine::init_session()
-{
-  const auto res = this->raw_exec("SET SESSION TIME ZONE 'UTC'");
-  if (!std::get<bool>(res))
-    log_error("Failed to set UTC timezone: ", std::get<std::string>(res));
-}
-long double PostgresqlEngine::epoch_to_floating_value(long double seconds) const
-{
-  return seconds;
-}
-
 #endif
diff --git a/src/database/postgresql_engine.hpp b/src/database/postgresql_engine.hpp
index 70215d4..1a9c249 100644
--- a/src/database/postgresql_engine.hpp
+++ b/src/database/postgresql_engine.hpp
@@ -23,22 +23,13 @@ class PostgresqlEngine: public DatabaseEngine
   ~PostgresqlEngine();
 
   static std::unique_ptr<DatabaseEngine> open(const std::string& string);
-  EngineType engine_type() const override
-  {
-    return EngineType::Postgresql;
-  }
 
-  std::map<std::string, std::string> get_all_columns_from_table(const std::string& table_name) override final;
+  std::set<std::string> get_all_columns_from_table(const std::string& table_name) override final;
   std::tuple<bool, std::string> raw_exec(const std::string& query) override final;
   std::unique_ptr<Statement> prepare(const std::string& query) override;
   void extract_last_insert_rowid(Statement& statement) override;
   std::string get_returning_id_sql_string(const std::string& col_name) override;
-  std::string id_column_type() const override;
-  std::string datetime_column_type() const override;
-  void convert_date_format(DatabaseEngine& engine) override;
-  long double epoch_to_floating_value(long double seconds) const override;
-  void init_session() override;
-  std::string escape_param_number(int nb) const override;
+  std::string id_column_type() override;
 private:
   PGconn* const conn;
 };
diff --git a/src/database/query.cpp b/src/database/query.cpp
index 6d20302..d72066e 100644
--- a/src/database/query.cpp
+++ b/src/database/query.cpp
@@ -21,13 +21,6 @@ void actual_bind(Statement& statement, const OptionalBool& value, int index)
     statement.bind_int64(index, -1);
 }
 
-void actual_bind(Statement& statement, const DateTime& value, int index)
-{
-  const auto epoch = value.epoch().count();
-  const auto result = std::to_string(static_cast<long double>(epoch) / std::chrono::system_clock::period::den);
-  statement.bind_text(index, result);
-}
-
 void actual_add_param(Query& query, const std::string& val)
 {
   query.params.push_back(val);
@@ -56,12 +49,3 @@ Query& operator<<(Query& query, const std::string& str)
   actual_add_param(query, str);
   return query;
 }
-
-Query& operator<<(Query& query, const DatetimeWriter& datetime_writer)
-{
-  query.body += datetime_writer.escape_param_number(query.current_param++);
-  actual_add_param(query, datetime_writer.get_value());
-  return query;
-}
-
-
diff --git a/src/database/query.hpp b/src/database/query.hpp
index 910271a..ba28b1a 100644
--- a/src/database/query.hpp
+++ b/src/database/query.hpp
@@ -3,7 +3,6 @@
 #include <biboumi.h>
 
 #include <utils/optional_bool.hpp>
-#include <utils/datetime.hpp>
 #include <database/statement.hpp>
 #include <database/column.hpp>
 
@@ -11,7 +10,6 @@
 
 #include <vector>
 #include <string>
-#include <database/datetime_writer.hpp>
 
 void actual_bind(Statement& statement, const std::string& value, int index);
 void actual_bind(Statement& statement, const std::int64_t& value, int index);
@@ -21,7 +19,6 @@ void actual_bind(Statement& statement, const T& value, int index)
   actual_bind(statement, static_cast<std::int64_t>(value), index);
 }
 void actual_bind(Statement& statement, const OptionalBool& value, int index);
-void actual_bind(Statement& statement, const DateTime& value, int index);
 
 #ifdef DEBUG_SQL_QUERIES
 #include <utils/scopetimer.hpp>
@@ -77,13 +74,15 @@ void actual_add_param(Query& query, const std::string& val);
 void actual_add_param(Query& query, const OptionalBool& val);
 
 template <typename T>
-typename std::enable_if<!std::is_arithmetic<T>::value, Query&>::type
+typename std::enable_if<!std::is_integral<T>::value, Query&>::type
 operator<<(Query& query, const T&)
 {
   query.body += T::name;
   return query;
 }
 
+Query& operator<<(Query& query, const char* str);
+Query& operator<<(Query& query, const std::string& str);
 template <typename Integer>
 typename std::enable_if<std::is_integral<Integer>::value, Query&>::type
 operator<<(Query& query, const Integer& i)
@@ -93,6 +92,3 @@ operator<<(Query& query, const Integer& i)
   return query;
 }
 
-Query& operator<<(Query& query, const char* str);
-Query& operator<<(Query& query, const std::string& str);
-Query& operator<<(Query& query, const DatetimeWriter& datetime);
diff --git a/src/database/select_query.cpp b/src/database/select_query.cpp
deleted file mode 100644
index 970b06c..0000000
--- a/src/database/select_query.cpp
+++ /dev/null
@@ -1,21 +0,0 @@
-#include <database/select_query.hpp>
-
-template <>
-std::string before_column<Database::Date>()
-{
-  if (Database::engine_type() == DatabaseEngine::EngineType::Sqlite3)
-    return "strftime(\"%Y-%m-%dT%H:%M:%SZ\", ";
-  else if (Database::engine_type() == DatabaseEngine::EngineType::Postgresql)
-    return "to_char(";
-  return {};
-}
-
-template <>
-std::string after_column<Database::Date>()
-{
-  if (Database::engine_type() == DatabaseEngine::EngineType::Sqlite3)
-    return ")";
-  else if (Database::engine_type() == DatabaseEngine::EngineType::Postgresql)
-    return R"(, 'YYYY-MM-DD"T"HH24:MM:SS"Z"'))";
-  return {};
-}
diff --git a/src/database/select_query.hpp b/src/database/select_query.hpp
index 0de4fe5..b9fdc06 100644
--- a/src/database/select_query.hpp
+++ b/src/database/select_query.hpp
@@ -5,8 +5,8 @@
 #include <database/table.hpp>
 #include <database/database.hpp>
 #include <database/statement.hpp>
-#include <utils/datetime.hpp>
 #include <database/query.hpp>
+#include <logger/logger.hpp>
 #include <database/row.hpp>
 
 #include <utils/optional_bool.hpp>
@@ -43,14 +43,6 @@ extract_row_value(Statement& statement, const int i)
   return result;
 }
 
-template <typename T>
-typename std::enable_if<std::is_same<DateTime, T>::value, T>::type
-extract_row_value(Statement& statement, const int i)
-{
-  const std::string timestamp = statement.get_column_text(i);
-  return {timestamp};
-}
-
 template <std::size_t N=0, typename... T>
 typename std::enable_if<N < sizeof...(T), void>::type
 extract_row_values(Row<T...>& row, Statement& statement)
@@ -68,24 +60,6 @@ typename std::enable_if<N == sizeof...(T), void>::type
 extract_row_values(Row<T...>&, Statement&)
 {}
 
-template <typename ColumnType>
-std::string before_column()
-{
-  return {};
-}
-
-template <typename ColumnType>
-std::string after_column()
-{
-  return {};
-}
-
-template <>
-std::string before_column<Database::Date>();
-
-template <>
-std::string after_column<Database::Date>();
-
 template <typename... T>
 struct SelectQuery: public Query
 {
@@ -104,8 +78,7 @@ struct SelectQuery: public Query
       using ColumnsType = std::tuple<T...>;
       using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnsType>()))>::type;
 
-      this->body += " ";
-      this->body += before_column<ColumnType>() + ColumnType::name + after_column<ColumnType>();
+      this->body += " " + std::string{ColumnType::name};
 
       if (N < (sizeof...(T) - 1))
         this->body += ", ";
diff --git a/src/database/sqlite3_engine.cpp b/src/database/sqlite3_engine.cpp
index b6ac1a1..5e3bba1 100644
--- a/src/database/sqlite3_engine.cpp
+++ b/src/database/sqlite3_engine.cpp
@@ -2,10 +2,7 @@
 
 #ifdef SQLITE3_FOUND
 
-#include <database/database.hpp>
-#include <database/select_query.hpp>
 #include <database/sqlite3_engine.hpp>
-
 #include <database/sqlite3_statement.hpp>
 
 #include <database/query.hpp>
@@ -24,17 +21,16 @@ Sqlite3Engine::~Sqlite3Engine()
   sqlite3_close(this->db);
 }
 
-std::map<std::string, std::string> Sqlite3Engine::get_all_columns_from_table(const std::string& table_name)
+std::set<std::string> Sqlite3Engine::get_all_columns_from_table(const std::string& table_name)
 {
-  std::map<std::string, std::string> result;
+  std::set<std::string> result;
   char* errmsg;
   std::string query{"PRAGMA table_info(" + table_name + ")"};
   int res = sqlite3_exec(this->db, query.data(), [](void* param, int columns_nb, char** columns, char**) -> int {
     constexpr int name_column = 1;
-    constexpr int data_type_column = 2;
-    auto* result = static_cast<std::map<std::string, std::string>*>(param);
-    if (name_column < columns_nb && data_type_column < columns_nb)
-      (*result)[utils::tolower(columns[name_column])] = utils::tolower(columns[data_type_column]);
+    std::set<std::string>* result = static_cast<std::set<std::string>*>(param);
+    if (name_column < columns_nb)
+      result->insert(utils::tolower(columns[name_column]));
     return 0;
   }, &result, &errmsg);
 
@@ -47,48 +43,6 @@ std::map<std::string, std::string> Sqlite3Engine::get_all_columns_from_table(con
   return result;
 }
 
-template <typename... T>
-static auto make_select_query(const Row<T...>&, const std::string& name)
-{
-  return SelectQuery<T...>{name};
-}
-
-void Sqlite3Engine::convert_date_format(DatabaseEngine& db)
-{
-  Transaction transaction{};
-  auto rollback = [&transaction] (const std::string& error_msg)
-  {
-    log_error("Failed to execute query: ", error_msg);
-    transaction.rollback();
-  };
-
-  const auto real_name = Database::muc_log_lines.get_name();
-  const auto tmp_name = real_name + "tmp_";
-  const std::string date_name = Database::Date::name;
-
-  auto result = db.raw_exec("ALTER TABLE " + real_name + " RENAME TO " + tmp_name);
-  if (!std::get<bool>(result))
-    return rollback(std::get<std::string>(result));
-
-  Database::muc_log_lines.create(db);
-
-  Database::OldMucLogLineTable old_muc_log_line(tmp_name);
-  auto select_query = make_select_query(old_muc_log_line.row(), old_muc_log_line.get_name());
-
-  auto& select_body = select_query.body;
-  auto begin = select_body.find(date_name);
-  select_body.replace(begin, date_name.size(), "julianday("+date_name+", 'unixepoch')");
-  select_body = "INSERT INTO " + real_name + " " + select_body;
-
-  result = db.raw_exec(select_body);
-  if (!std::get<bool>(result))
-    return rollback(std::get<std::string>(result));
-
-  result = db.raw_exec("DROP TABLE " + tmp_name);
-  if (!std::get<bool>(result))
-    return rollback(std::get<std::string>(result));
-}
-
 std::unique_ptr<DatabaseEngine> Sqlite3Engine::open(const std::string& filename)
 {
   sqlite3* new_db;
@@ -138,19 +92,9 @@ void Sqlite3Engine::extract_last_insert_rowid(Statement&)
   this->last_inserted_rowid = sqlite3_last_insert_rowid(this->db);
 }
 
-std::string Sqlite3Engine::id_column_type() const
+std::string Sqlite3Engine::id_column_type()
 {
   return "INTEGER PRIMARY KEY AUTOINCREMENT";
 }
 
-std::string Sqlite3Engine::datetime_column_type() const
-{
-  return "REAL";
-}
-
-long double Sqlite3Engine::epoch_to_floating_value(long double d) const
-{
-  return (d / 86400.0) + 2440587.5;
-}
-
 #endif
diff --git a/src/database/sqlite3_engine.hpp b/src/database/sqlite3_engine.hpp
index 1b37e8c..a7bfcdb 100644
--- a/src/database/sqlite3_engine.hpp
+++ b/src/database/sqlite3_engine.hpp
@@ -23,19 +23,12 @@ class Sqlite3Engine: public DatabaseEngine
   ~Sqlite3Engine();
 
   static std::unique_ptr<DatabaseEngine> open(const std::string& string);
-  EngineType engine_type() const override
-  {
-    return EngineType::Sqlite3;
-  }
 
-  std::map<std::string, std::string> get_all_columns_from_table(const std::string& table_name) override final;
+  std::set<std::string> get_all_columns_from_table(const std::string& table_name) override final;
   std::tuple<bool, std::string> raw_exec(const std::string& query) override final;
   std::unique_ptr<Statement> prepare(const std::string& query) override;
   void extract_last_insert_rowid(Statement& statement) override;
-  std::string id_column_type() const override;
-  std::string datetime_column_type() const override;
-  void convert_date_format(DatabaseEngine&) override;
-  long double epoch_to_floating_value(long double d) const override;
+  std::string id_column_type() override;
 private:
   sqlite3* const db;
 };
diff --git a/src/database/table.hpp b/src/database/table.hpp
index 4c96151..0b8bfc0 100644
--- a/src/database/table.hpp
+++ b/src/database/table.hpp
@@ -18,8 +18,6 @@ std::string ToSQLType(DatabaseEngine& db)
     return db.id_column_type();
   else if (std::is_same<typename T::real_type, std::string>::value)
     return "TEXT";
-  else if (std::is_same<typename T::real_type, DateTime>::value)
-    return db.datetime_column_type();
   else
     return "INTEGER";
 }
@@ -98,16 +96,16 @@ class Table
 
   template <std::size_t N=0>
   typename std::enable_if<N < sizeof...(T), void>::type
-  add_column_if_not_exists(DatabaseEngine& db, const std::map<std::string, std::string>& existing_columns)
+  add_column_if_not_exists(DatabaseEngine& db, const std::set<std::string>& existing_columns)
   {
     using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<ColumnTypes>()))>::type;
-    if (existing_columns.find(ColumnType::name) == existing_columns.end())
+    if (existing_columns.count(ColumnType::name) == 0)
       add_column_to_table<ColumnType>(db, this->name);
     add_column_if_not_exists<N+1>(db, existing_columns);
   }
   template <std::size_t N=0>
   typename std::enable_if<N == sizeof...(T), void>::type
-  add_column_if_not_exists(DatabaseEngine&, const std::map<std::string, std::string>&)
+  add_column_if_not_exists(DatabaseEngine&, const std::set<std::string>&)
   {}
 
   template <std::size_t N=0>
diff --git a/src/utils/datetime.hpp b/src/utils/datetime.hpp
deleted file mode 100644
index 656b318..0000000
--- a/src/utils/datetime.hpp
+++ /dev/null
@@ -1,56 +0,0 @@
-#pragma once
-
-#include <chrono>
-#include <string>
-
-#include <logger/logger.hpp>
-
-class DateTime
-{
-public:
-  enum class Engine {
-    Postgresql,
-    Sqlite3,
-  } engine{Engine::Sqlite3};
-
-  using time_point = std::chrono::system_clock::time_point;
-
-  DateTime():
-      s{},
-      t{}
-  { }
-
-  DateTime(std::time_t t):
-      t(std::chrono::seconds(t))
-  {}
-
-  DateTime(std::string s):
-      s(std::move(s))
-  {}
-
-  DateTime& operator=(const std::string& s)
-  {
-    this->s = s;
-    return *this;
-  }
-
-  DateTime& operator=(const time_point t)
-  {
-    this->t = t;
-    return *this;
-  }
-
-  const std::string& to_string() const
-  {
-    return this->s;
-  }
-
-  time_point::duration epoch() const
-  {
-    return this->t.time_since_epoch();
-  }
-
-private:
-  std::string s;
-  time_point t;
-};
diff --git a/src/xmpp/biboumi_component.cpp b/src/xmpp/biboumi_component.cpp
index 95b38f0..6dc5fc5 100644
--- a/src/xmpp/biboumi_component.cpp
+++ b/src/xmpp/biboumi_component.cpp
@@ -805,7 +805,7 @@ void BiboumiComponent::send_archived_message(const Database::MucLogLine& log_lin
 
     XmlSubNode delay(forwarded, "delay");
     delay["xmlns"] = DELAY_NS;
-    delay["stamp"] = log_line.col<Database::Date>().to_string();
+    delay["stamp"] = utils::to_string(log_line.col<Database::Date>());
 
     XmlSubNode submessage(forwarded, "message");
     submessage["xmlns"] = CLIENT_NS;
diff --git a/src/xmpp/xmpp_component.cpp b/src/xmpp/xmpp_component.cpp
index bec88ea..b3d925e 100644
--- a/src/xmpp/xmpp_component.cpp
+++ b/src/xmpp/xmpp_component.cpp
@@ -399,7 +399,7 @@ void XmppComponent::send_muc_message(const std::string& muc_name, const std::str
 }
 
 #ifdef USE_DATABASE
-void XmppComponent::send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body_txt, const std::string& jid_to, const DateTime& timestamp)
+void XmppComponent::send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body_txt, const std::string& jid_to, Database::time_point::rep timestamp)
 {
   Stanza message("message");
   message["to"] = jid_to;
@@ -417,7 +417,7 @@ void XmppComponent::send_history_message(const std::string& muc_name, const std:
     XmlSubNode delay(message, "delay");
     delay["xmlns"] = DELAY_NS;
     delay["from"] = muc_name + "@" + this->served_hostname;
-    delay["stamp"] = timestamp.to_string();
+    delay["stamp"] = utils::to_string(timestamp);
   }
 
   this->send_stanza(message);
diff --git a/src/xmpp/xmpp_component.hpp b/src/xmpp/xmpp_component.hpp
index 960c801..e18da40 100644
--- a/src/xmpp/xmpp_component.hpp
+++ b/src/xmpp/xmpp_component.hpp
@@ -6,7 +6,6 @@
 #include <network/tcp_client_socket_handler.hpp>
 #include <database/database.hpp>
 #include <xmpp/xmpp_parser.hpp>
-#include <utils/datetime.hpp>
 #include <xmpp/body.hpp>
 
 #include <unordered_map>
@@ -142,7 +141,7 @@ public:
    * Send a message, with a <delay/> element, part of a MUC history
    */
   void send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body,
-                            const std::string& jid_to, const DateTime& timestamp);
+                            const std::string& jid_to, Database::time_point::rep timestamp);
 #endif
   /**
    * Send an unavailable presence for this nick
diff --git a/tests/end_to_end/__main__.py b/tests/end_to_end/__main__.py
index 6c575a8..82321eb 100644
--- a/tests/end_to_end/__main__.py
+++ b/tests/end_to_end/__main__.py
@@ -1953,7 +1953,7 @@ if __name__ == '__main__':
                     <query xmlns='urn:xmpp:mam:2' queryid='qid3'>
                     <x xmlns='jabber:x:data' type='submit'>
                     <field var='FORM_TYPE' type='hidden'> <value>urn:xmpp:mam:2</value></field>
-                    <field var='start'><value>2222-06-07T00:00:00Z</value></field>
+                    <field var='start'><value>3016-06-07T00:00:00Z</value></field>
                     </x>
                     </query></iq>"""),