Started to migrate postgresql connector into sqlpp11 repo.

Removed timezone handling in the process (needs to be documented).
Note: on_conflict does not check for constraints (needs to be documented).
Note: some of the constraints tests seem to be aiming for a different static_assert.

CMakeLists.txt

@@ -39,25 +39,31 @@ option(SQLCIPHER_CONNECTOR "Build SQLite3 Connector with SQLCipher" OFF)
 if(MYSQL_CONNECTOR)
   find_package(MySQL REQUIRED)
 else()
-  message(STATUS "Not building MYSQL_CONNECTOR")
+  message(STATUS "Not building tests for MYSQL_CONNECTOR")
 endif()
 
 if(MARIADB_CONNECTOR)
   find_package(MariaDB REQUIRED)
 else()
-  message(STATUS "Not building MARIAB_CONNECTOR")
+  message(STATUS "Not building tests for MARIAB_CONNECTOR")
+endif()
+
+if(POSTGRESQL_CONNECTOR)
+  find_package(PostgreSQL REQUIRED)
+else()
+  message(STATUS "Not building tests for POSTGRESQL_CONNECTOR")
 endif()
 
 if(SQLITE3_CONNECTOR)
   find_package(SQLite3 REQUIRED)
 else()
-  message(STATUS "Not building SQLITE3_CONNECTOR")
+  message(STATUS "Not building tests for SQLITE3_CONNECTOR")
 endif()
 
 if(SQLCIPHER_CONNECTOR)
   find_package(SQLCipher REQUIRED)
 else()
-  message(STATUS "Not building SQLCIPHER_CONNECTOR")
+  message(STATUS "Not building tests for SQLCIPHER_CONNECTOR")
 endif()
 
 include(CTest)

include/sqlpp11/detail/column_tuple_merge.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2021-2021, Roland Bock
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *   Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ *   Redistributions in binary form must reproduce the above copyright notice, this
+ *   list of conditions and the following disclaimer in the documentation and/or
+ *   other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SQLPP11_COLUMN_TUPLE_MERGE_H
+#define SQLPP11_COLUMN_TUPLE_MERGE_H
+
+#include <tuple>
+
+#include <sqlpp11/auto_alias.h>
+
+namespace sqlpp
+{
+  namespace detail
+  {
+    template <typename T>
+    std::tuple<auto_alias_t<T>> as_column_tuple(T t)
+    {
+      return std::tuple<auto_alias_t<T>>(auto_alias_t<T>{t});
+    }
+
+    template <typename... Args>
+    std::tuple<auto_alias_t<Args>...> as_column_tuple(std::tuple<Args...> t)
+    {
+      return t;
+    }
+
+    template <typename... Columns>
+    auto column_tuple_merge(Columns... columns) -> decltype(std::tuple_cat(as_column_tuple(columns)...))
+    {
+      return std::tuple_cat(as_column_tuple(columns)...);
+    }
+  }
+}  // namespace sqlpp
+
+#endif