From 4178942015cde7941903d9b89b21f2890a485b50 Mon Sep 17 00:00:00 2001
From: Roland Bock <rbock@eudoxos.de>
Date: Sun, 13 Jun 2021 07:51:20 +0200
Subject: [PATCH] Document multi_insert for time_point columns (#367)

---
 docs/Insert.md   | 19 ++++++++++++++++++-
 tests/Insert.cpp |  9 +++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/docs/Insert.md b/docs/Insert.md
index ff31b84f..f1375046 100644
--- a/docs/Insert.md
+++ b/docs/Insert.md
@@ -2,6 +2,8 @@ Haven't found the time to document this in any detail, yet, but this is an examp
 
 ```C++
 db(insert_into(tab).set(tab.gamma = true));
+db(insert_into(tabDateTime)
+      .set(tabDateTime.colTimePoint = std::chrono::system_clock::now()));
 ```
 
 This is how you could insert multiple rows at a time:
@@ -15,4 +17,19 @@ multi_insert.values.add(t.gamma = sqlpp::value_or_null(true),
                         t.beta = sqlpp::value_or_null("pie"),
                         t.delta = sqlpp::value_or_null<sqlpp::integer>(sqlpp::null));
 db(multi_insert);
-```
\ No newline at end of file
+```
+
+Note that `add` currently requires precise value types, equal to the respective column's value
+type. For instance, time point columns are represented as
+`std::chrono::time_point<std::chrono::system_clock, std::chrono::microseconds>`.
+
+Thus, when using such a column in a `multi_insert`, you might have to cast to the right
+time point.
+
+```
+  auto multi_time_insert = insert_into(tabDateTime).columns(tabDateTime.colTimePoint);
+  multi_time_insert.values.add(tabDateTime.colTimePoint = std::chrono::time_point_cast<std::chrono::microseconds>(
+                                   std::chrono::system_clock::now()));
+```
+
+Similar for other data types.
diff --git a/tests/Insert.cpp b/tests/Insert.cpp
index 34e3a48c..85a0571d 100644
--- a/tests/Insert.cpp
+++ b/tests/Insert.cpp
@@ -35,6 +35,7 @@ int Insert(int, char*[])
   MockDb db = {};
   MockDb::_serializer_context_t printer = {};
   const auto t = test::TabBar{};
+  const auto tabDateTime = test::TabDateTime{};
   // test::TabFoo f;
 
   {
@@ -71,6 +72,14 @@ int Insert(int, char*[])
   printer.reset();
   std::cerr << serialize(multi_insert, printer).str() << std::endl;
 
+  // Beware, you need exact types for inserted values in multi_insert
+  insert_into(tabDateTime)
+      .set(tabDateTime.colTimePoint = std::chrono::system_clock::now());
+
+  auto multi_time_insert = insert_into(tabDateTime).columns(tabDateTime.colTimePoint);
+  multi_time_insert.values.add(tabDateTime.colTimePoint = std::chrono::time_point_cast<std::chrono::microseconds>(
+                                   std::chrono::system_clock::now()));
+
   auto i = dynamic_insert_into(db, t).dynamic_set();
   i.insert_list.add(t.beta = "kirschauflauf");
   printer.reset();