MT#57223 add virtual_child_sound_sets

* virtual_child_sound_sets is a virtual view that fetches
  all child sound sets of the one that is defined as a placeholder
  argument

Change-Id: I74b38328130cbb85cb0d559033408620f721caa2

lib/NGCP/Schema/Result/virtual_child_sound_sets.pm

@@ -0,0 +1,59 @@
+package NGCP::Schema::Result::virtual_child_sound_sets;
+
+use strict;
+use warnings;
+
+use Scalar::Util qw(blessed);
+use parent qw/DBIx::Class::Core/;
+
+our $VERSION = '2.007';
+
+__PACKAGE__->table_class('DBIx::Class::ResultSource::View');
+__PACKAGE__->table("virtual_child_sound_sets");
+
+__PACKAGE__->add_columns(
+  "id",
+  {
+    data_type => "integer",
+    extra => { unsigned => 1 },
+    is_auto_increment => 1,
+    is_nullable => 0,
+  },
+  "name",
+  {
+    data_type => "varchar",
+    is_nullable => 0,
+    size => 256,
+  },
+  "parent_chain",
+  {
+    data_type => "varchar",
+    is_nullable => 0,
+    size => 1024,
+  },
+);
+
+__PACKAGE__->set_primary_key("id");
+__PACKAGE__->result_source_instance->is_virtual(1);
+__PACKAGE__->result_source_instance->view_definition(<<'SQL');
+WITH RECURSIVE cte as (
+    SELECT id, name,
+           JSON_ARRAY(id) AS parent_chain
+      FROM voip_sound_sets
+     WHERE id = ?
+    UNION ALL
+    SELECT s.id, s.name,
+           JSON_ARRAY_INSERT(cte.parent_chain, "$[0]", s.id) AS parent_chain
+      FROM voip_sound_sets s
+      JOIN cte ON cte.id = s.parent_id
+)
+SELECT cte.id, cte.name,
+       REPLACE(REPLACE(REPLACE(
+          JSON_REMOVE(cte.parent_chain, "$[0]"),
+          "[", ""), "]", ""), ", ", ":"
+       ) AS parent_chain
+  FROM cte
+SQL
+
+1;
+