added TinyBuilder::touch()

 - added unit tests
 - added model proxy touchAll()
 - added docs

docs/tinyorm/getting-started.mdx

@@ -249,6 +249,24 @@ You can make these static constants non-inline and initialize them in the cpp fi
 You may also use `Orm::CREATED_AT` and `Orm::UPDATED_AT` string constants instead of `QStringLiteral("created_at")`.
 :::
 
+#### Touching timestamps
+
+You can explicitly touch timestamps using the `touch` method defined on the Model:
+
+    auto flight = Flight::find(1);
+
+    flight->touch();
+    flight->touch("added_on"); // Custom column name
+
+You can also touch multiple rows at once using the `touch` method defined on the TinyBuilder:
+
+    auto [affected, query] = Flight::whereEq("status", "new")->touch();
+
+The `touch` method may also be called when building a [relationship](/tinyorm/relationships.mdx) query:
+
+    flight->history()->touch();
+    flight->history()->whereEq("status", "new").touch();
+
 ### Database Connections
 
 By default, all TinyORM models will use the default database connection that is configured for your application. If you would like to specify a different connection that should be used when interacting with a particular model, you should define a `u_connection` private data member on the model:

include/orm/tiny/modelproxies.hpp

@@ -225,6 +225,11 @@ namespace Tiny
         /*! Run a truncate statement on the table. */
         static void truncate();
 
+        /* Touching timestamps */
+        /*! Update the column's update timestamp on all Models. */
+        static std::tuple<int, std::optional<QSqlQuery>>
+        touchAll(const QString &column = "");
+
         /* Select */
         /*! Retrieve the "count" result of the query. */
         static quint64 count(const QVector<Column> &columns = {ASTERISK});
@@ -1417,6 +1422,15 @@ namespace Tiny
         query()->truncate();
     }
 
+    /* Touching timestamps */
+
+    template<typename Derived, AllRelationsConcept ...AllRelations>
+    std::tuple<int, std::optional<QSqlQuery>>
+    ModelProxies<Derived, AllRelations...>::touchAll(const QString &column)
+    {
+        return query()->touch(column);
+    }
+
     /* Select */
 
     template<typename Derived, AllRelationsConcept ...AllRelations>

include/orm/tiny/tinybuilder.hpp

@@ -191,6 +191,10 @@ namespace Orm::Tiny
         Model updateOrCreate(const QVector<WhereItem> &attributes,
                              const QVector<AttributeItem> &values = {});
 
+        /*! Update the column's update timestamp. */
+        std::tuple<int, std::optional<QSqlQuery>>
+        touch(const QString &column = "");
+
         /* QueryBuilder proxy methods that need modifications */
         /*! Update records in the database. */
         std::tuple<int, QSqlQuery>
@@ -838,6 +842,23 @@ namespace Orm::Tiny
         return instance;
     }
 
+    template<typename Model>
+    std::tuple<int, std::optional<QSqlQuery>>
+    Builder<Model>::touch(const QString &column)
+    {
+        auto time = m_model.freshTimestamp();
+
+        if (!column.isEmpty())
+            return toBase().update({{column, std::move(time)}});
+
+        const auto &updatedAtColumn = m_model.getUpdatedAtColumn();
+
+        if (!m_model.usesTimestamps() || updatedAtColumn.isEmpty())
+            return {0, std::nullopt};
+
+        return toBase().update({{updatedAtColumn, std::move(time)}});
+    }
+
     /* QueryBuilder proxy methods that need modifications */
 
     template<typename Model>

tests/auto/unit/orm/tiny/mysql_tinybuilder/tst_mysql_tinybuilder.cpp

@@ -39,6 +39,10 @@ class tst_MySql_TinyBuilder : public QObject // clazy:exclude=ctor-missing-paren
 private slots:
     void initTestCase();
 
+    void touch() const;
+    void touch_CustomColumn() const;
+    void touch_NotUsesTimestamps() const;
+
     /* Querying Relationship Existence/Absence on HasMany */
     void has_Basic_OnHasMany() const;
     void has_Count_OnHasMany() const;
@@ -113,6 +117,79 @@ void tst_MySql_TinyBuilder::initTestCase()
               .toUtf8().constData(), );
 }
 
+void tst_MySql_TinyBuilder::touch() const
+{
+    auto timeBeforeTouch = QDateTime::currentDateTime();
+    // Reset milliseconds to 0
+    {
+        auto time = timeBeforeTouch.time();
+        timeBeforeTouch.setTime(QTime(time.hour(), time.minute(), time.second()));
+    }
+
+    auto log = DB::connection(m_connection).pretend([this]
+    {
+        User::on(m_connection)
+                ->whereEq("status", "new")
+                .touch();
+    });
+
+    QCOMPARE(log.size(), 1);
+    const auto &firstLog = log.first();
+
+    QCOMPARE(firstLog.query,
+             "update `users` "
+             "set `updated_at` = ? "
+             "where `status` = ? and `users`.`deleted_at` is null");
+    QVERIFY(firstLog.boundValues.size() == 2);
+    QVERIFY(firstLog.boundValues.at(0).value<QDateTime>() >= timeBeforeTouch);
+    QCOMPARE(firstLog.boundValues.at(1), QVariant(QString("new")));
+}
+
+void tst_MySql_TinyBuilder::touch_CustomColumn() const
+{
+    auto timeBeforeTouch = QDateTime::currentDateTime();
+    // Reset milliseconds to 0
+    {
+        auto time = timeBeforeTouch.time();
+        timeBeforeTouch.setTime(QTime(time.hour(), time.minute(), time.second()));
+    }
+
+    auto log = DB::connection(m_connection).pretend([this]
+    {
+        User::on(m_connection)
+                ->whereEq("status", "new")
+                .touch("updated_on");
+    });
+
+    QCOMPARE(log.size(), 1);
+    const auto &firstLog = log.first();
+
+    QCOMPARE(firstLog.query,
+             "update `users` "
+             "set `updated_on` = ? "
+             "where `status` = ? and `users`.`deleted_at` is null");
+    QVERIFY(firstLog.boundValues.size() == 2);
+    QVERIFY(firstLog.boundValues.at(0).value<QDateTime>() >= timeBeforeTouch);
+    QCOMPARE(firstLog.boundValues.at(1), QVariant(QString("new")));
+}
+
+void tst_MySql_TinyBuilder::touch_NotUsesTimestamps() const
+{
+    int affected = -1;
+    std::optional<QSqlQuery> query = std::nullopt;
+
+    auto log = DB::connection(m_connection).pretend([this, &affected, &query]
+    {
+        std::tie(affected, query) = Phone::on(m_connection)
+                                    ->whereEq("status", "new")
+                                    .touch();
+    });
+
+    QVERIFY(log.isEmpty());
+    QCOMPARE(affected, 0);
+    QCOMPARE(query, std::nullopt);
+}
+
 void tst_MySql_TinyBuilder::has_Basic_OnHasMany() const
 {
     auto builder = createTinyQuery<Torrent>();