CRM-12986 fix schema so required fields are required / not null

CRM/Upgrade/Incremental/sql/4.4.alpha1.mysql.tpl

@@ -69,3 +69,8 @@ VALUES
 -- CRM-12809
 ALTER TABLE `civicrm_custom_group`
   ADD COLUMN `is_reserved` tinyint(4) DEFAULT '0' COMMENT 'Is this a reserved Custom Group?';
+
+--CRM-12986 fix event_id & contact_id to NOT NULL fields on participant table
+ALTER TABLE `civicrm_participant`
+  CHANGE COLUMN `event_id` `event_id` INT(10) UNSIGNED NOT NULL,
+  CHANGE COLUMN `contact_id` `contact_id` INT(10) UNSIGNED NOT NULL;

xml/schema/Event/Participant.xml

@@ -28,7 +28,7 @@
       <title>Contact ID</title>
       <headerPattern>/contact(.?id)?/i</headerPattern>
       <import>true</import>
-      <default>0</default>
+      <required>true</required>
       <comment>FK to Contact ID</comment>
       <add>1.7</add>
   </field>
@@ -44,7 +44,7 @@
       <title>Event</title>
       <import>true</import>
       <headerPattern>/event id$/i</headerPattern>
-      <default>0</default>
+      <required>true</required>
       <comment>FK to Event ID</comment>
       <add>1.7</add>
   </field>