Add functions for getting main synonym in list of synonyms

src/NodaLinkedEntityGetter.php

@@ -117,4 +117,60 @@ final class NodaLinkedEntityGetter {
         return array_keys($output);
 
     }
+
+    /**
+     * Returns the main synonym of a tag (or the tag ID itself, if there are
+     * no synonyms).
+     *
+     * @param MDMysqli $mysqli_noda DB connection.
+     * @param integer  $tag_id      ID of the tag to check.
+     *
+     * @return integer
+     */
+    public static function getMainTagSynonymId(MDMysqli $mysqli_noda, int $tag_id):int {
+
+        $result = $mysqli_noda->query_by_stmt("SELECT `tag_syn_main`
+            FROM `tag_syn`
+            WHERE `tag_syn_sub` = ?
+            LIMIT 1", "i", $tag_id);
+
+        if ($cur = $result->fetch_row()) {
+            $output = MD_STD_IN::sanitize_id($cur[0]);
+        }
+        else {
+            $output = $tag_id;
+        }
+        $result->close();
+
+        return $output;
+
+    }
+
+    /**
+     * Returns the main synonym of a place (or the place ID itself, if there are
+     * no synonyms).
+     *
+     * @param MDMysqli $mysqli_noda DB connection.
+     * @param integer  $place_id    ID of the place to check.
+     *
+     * @return integer
+     */
+    public static function getMainPlaceSynonymId(MDMysqli $mysqli_noda, int $place_id):int {
+
+        $result = $mysqli_noda->query_by_stmt("SELECT `ort_syn_main`
+            FROM `ort_syn`
+            WHERE `ort_syn_sub` = ?
+            LIMIT 1", "i", $place_id);
+
+        if ($cur = $result->fetch_row()) {
+            $output = MD_STD_IN::sanitize_id($cur[0]);
+        }
+        else {
+            $output = $place_id;
+        }
+        $result->close();
+
+        return $output;
+
+    }
 }