CRM-13739 - Transaction ID limited to 16chars when exporting event participations

http://issues.civicrm.org/jira/browse/CRM-13739

CRM/Export/BAO/Export.php

@@ -1276,7 +1276,19 @@ INSERT INTO {$componentTable} SELECT distinct gc.contact_id FROM civicrm_group_c
     }
     else {
       if (substr($fieldName, -3, 3) == '_id') {
-        $sqlColumns[$fieldName] = "$fieldName varchar(16)";
+        // for trxn_id and its variants use a longer buffer
+        // to accomodate different systems - CRM-13739
+        static $notRealIDFields = NULL;
+        if ($notRealIDFields == NULL) {
+          $notRealIDFields = array( 'trxn_id', 'componentpaymentfield_transaction_id' );
+        }
+
+        if (in_array($fieldName, $notRealIDFields)) {
+          $sqlColumns[$fieldName] = "$fieldName varchar(255)";
+        }
+        else {
+          $sqlColumns[$fieldName] = "$fieldName varchar(16)";
+        }
       }
       else {
         $changeFields = array(