diff --git a/src/flex-table.cpp b/src/flex-table.cpp
index ce2a220fb..562bbe744 100644
--- a/src/flex-table.cpp
+++ b/src/flex-table.cpp
@@ -14,6 +14,7 @@
 #include "pgsql-helper.hpp"
 #include "util.hpp"
 
+#include <algorithm>
 #include <cassert>
 #include <string>
 
@@ -64,6 +65,73 @@ std::string flex_table_t::full_tmp_name() const
     return qualified_name(schema(), name() + "_tmp");
 }
 
+bool flex_table_t::has_id_column() const noexcept
+{
+    if (m_columns.empty()) {
+        return false;
+    }
+    return (m_columns[0].type() == table_column_type::id_type) ||
+           (m_columns[0].type() == table_column_type::id_num);
+}
+
+bool flex_table_t::has_hstore_column() const noexcept
+{
+    auto const it = std::find_if(begin(), end(), [&](auto const &column) {
+        return column.type() == table_column_type::hstore;
+    });
+    return it != end();
+}
+
+bool flex_table_t::matches_type(osmium::item_type type) const noexcept
+{
+    // This table takes any type -> okay
+    if (m_id_type == osmium::item_type::undefined) {
+        return true;
+    }
+
+    // Type and table type match -> okay
+    if (type == m_id_type) {
+        return true;
+    }
+
+    // Relations can be written as linestrings into way tables -> okay
+    if (type == osmium::item_type::relation &&
+        m_id_type == osmium::item_type::way) {
+        return true;
+    }
+
+    // Area tables can take ways or relations, but not nodes
+    return m_id_type == osmium::item_type::area &&
+           type != osmium::item_type::node;
+}
+
+/// Map way/node/relation ID to id value used in database table column
+osmid_t flex_table_t::map_id(osmium::item_type type, osmid_t id) const noexcept
+{
+    if (m_id_type == osmium::item_type::undefined) {
+        if (has_multicolumn_id_index()) {
+            return id;
+        }
+
+        switch (type) {
+        case osmium::item_type::node:
+            return id;
+        case osmium::item_type::way:
+            return -id;
+        case osmium::item_type::relation:
+            return -id - 100000000000000000LL;
+        default:
+            assert(false);
+        }
+    }
+
+    if (m_id_type != osmium::item_type::relation &&
+        type == osmium::item_type::relation) {
+        return -id;
+    }
+    return id;
+}
+
 flex_table_column_t &flex_table_t::add_column(std::string const &name,
                                               std::string const &type,
                                               std::string const &sql_type)
diff --git a/src/flex-table.hpp b/src/flex-table.hpp
index 39ce3b810..3bfcdb5c6 100644
--- a/src/flex-table.hpp
+++ b/src/flex-table.hpp
@@ -84,14 +84,7 @@ class flex_table_t
 
     void set_id_type(osmium::item_type type) noexcept { m_id_type = type; }
 
-    bool has_id_column() const noexcept
-    {
-        if (m_columns.empty()) {
-            return false;
-        }
-        return (m_columns[0].type() == table_column_type::id_type) ||
-               (m_columns[0].type() == table_column_type::id_num);
-    }
+    bool has_id_column() const noexcept;
 
     std::size_t num_columns() const noexcept { return m_columns.size(); }
 
@@ -110,13 +103,7 @@ class flex_table_t
         return m_geom_column != std::numeric_limits<std::size_t>::max();
     }
 
-    bool has_hstore_column() const noexcept
-    {
-        auto const it = std::find_if(begin(), end(), [&](auto const &column) {
-            return column.type() == table_column_type::hstore;
-        });
-        return it != end();
-    }
+    bool has_hstore_column() const noexcept;
 
     /// Get the (first, if there are multiple) geometry column.
     flex_table_column_t const &geom_column() const noexcept
@@ -140,55 +127,10 @@ class flex_table_t
     std::string build_sql_create_id_index() const;
 
     /// Does this table take objects of the specified type?
-    bool matches_type(osmium::item_type type) const noexcept
-    {
-        // This table takes any type -> okay
-        if (m_id_type == osmium::item_type::undefined) {
-            return true;
-        }
-
-        // Type and table type match -> okay
-        if (type == m_id_type) {
-            return true;
-        }
-
-        // Relations can be written as linestrings into way tables -> okay
-        if (type == osmium::item_type::relation &&
-            m_id_type == osmium::item_type::way) {
-            return true;
-        }
-
-        // Area tables can take ways or relations, but not nodes
-        return m_id_type == osmium::item_type::area &&
-               type != osmium::item_type::node;
-    }
+    bool matches_type(osmium::item_type type) const noexcept;
 
     /// Map way/node/relation ID to id value used in database table column
-    osmid_t map_id(osmium::item_type type, osmid_t id) const noexcept
-    {
-        if (m_id_type == osmium::item_type::undefined) {
-            if (has_multicolumn_id_index()) {
-                return id;
-            }
-
-            switch (type) {
-            case osmium::item_type::node:
-                return id;
-            case osmium::item_type::way:
-                return -id;
-            case osmium::item_type::relation:
-                return -id - 100000000000000000LL;
-            default:
-                assert(false);
-            }
-        }
-
-        if (m_id_type != osmium::item_type::relation &&
-            type == osmium::item_type::relation) {
-            return -id;
-        }
-        return id;
-    }
+    osmid_t map_id(osmium::item_type type, osmid_t id) const noexcept;
 
     flex_table_column_t &add_column(std::string const &name,
                                     std::string const &type,