diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index e009c5f..aa398de 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -4,7 +4,7 @@ namespace metagen_go;
 use Exception;
 use Twig\{TwigTest, TwigFilter, TwigFunction};
 
-function get_twig(array $inc_path = [])
+function get_twig(array $inc_path = []): \Twig\Environment
 {
   array_unshift($inc_path, __DIR__ . "/../tpl/");
   $loader = new \Twig\Loader\FilesystemLoader($inc_path);
@@ -165,6 +165,10 @@ function add_twig_filters(\Twig\Environment $twig)
     'varname', 
     fn(\mtgMetaField $field): string => lcfirst(snake2camel($field->getName()))
   ));  
+  $twig->addFilter(new TwigFilter(
+    'tname', 
+    fn(\mtgMetaField $field): string => $field->getType() instanceof \mtgArrType ? $field->getType()->getValue()->getName() : $field->getType()->getName()
+  ));
   $twig->addFilter(new TwigFilter(
     'builtin_type_suffix', 
     fn (\mtgBuiltinType $type): string => builtin_type_method_suffix($type),
@@ -173,6 +177,33 @@ function add_twig_filters(\Twig\Environment $twig)
     'default_val', 
     fn(\mtgMetaField $field) => default_value($field)
   ));
+  $twig->addFilter(new TwigFilter(
+    'fields', 
+    function (\mtgMetaField $field): array {
+      $type = $field->getType();
+      if($type instanceof \mtgArrType)
+      {
+        $type = $type->getValue();
+      }
+      return $type->getFields();
+    }
+  ));
+  $twig->addFilter(new TwigFilter(
+    'pk_fields', 
+    function (\mtgMetaField $field): array {
+      $type = $field->getType();
+      if($type instanceof \mtgArrType)
+      {
+        $type = $type->getValue();
+      }
+      $pkey = explode(',', $type->getToken('table_pkey'));
+      $fields = [];
+      foreach ($pkey as $fieldName) {
+        $fields[] = $type->getField($fieldName);
+      }
+      return $fields;
+    }
+  ));
 
   $twig->addFilter(new TwigFilter(
     'rpc_invert',
diff --git a/tpl/macros_struct.twig b/tpl/macros_struct.twig
index 252a626..d2280ed 100644
--- a/tpl/macros_struct.twig
+++ b/tpl/macros_struct.twig
@@ -43,7 +43,7 @@
 
 type {{ s.name }} struct {
   {%~ for f in pkey %}
-  {{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }}" msgpack:"{{ f|alias }}"`
+  {{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }},string" msgpack:"{{ f|alias }}"`
   {%~ endfor %}
 
 	{{ json_fields_type }}
@@ -51,7 +51,7 @@ type {{ s.name }} struct {
 
 type {{ json_fields_type }} struct{
 	{%~ for f in json_fields %}
-  {{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }}" msgpack:"{{ f|alias }}"`
+  {{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }},string" msgpack:"{{ f|alias }}"`
   {%~ endfor %}
 
 	changedFields meta.ChangedFields
@@ -847,7 +847,7 @@ type {{ s.name }} struct {
 	{% endif %}
 
 	{% for f in s.fields %}
-	{{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }}" msgpack:"{{ f|alias }}"`
+	{{ f|fname }} {{ f.type|go_type }} `json:"{{ f|alias }},string" msgpack:"{{ f|alias }}"`
 	{% endfor %}
 
 	{% if has_token(s, 'bitfields') %}