change the likes db structure to make it more easily importable/exportable

install/update.php

@@ -1,6 +1,6 @@
 <?php
 
-define( 'UPDATE_VERSION' , 1148 );
+define( 'UPDATE_VERSION' , 1149 );
 
 /**
  *
@@ -1714,3 +1714,22 @@ function update_r1147() {
     return UPDATE_FAILED;
 }
 
+function update_r1148() {
+    $r1 = q("alter table likes add i_mid char(255) not null default '' ");
+    $r2 = q("create index i_mid on likes ( i_mid ) ");
+
+	$r3 = q("select likes.*, item.mid from from likes left join item on likes.iid = item.id");
+	if($r3) {
+		foreach($r3 as $rr) {
+			q("update likes set i_mid = '%s' where id = $d",
+				dbesc($rr['mid']),
+				intval($rr['id'])
+			);
+		}
+	}
+
+    if($r1 && $r2)
+        return UPDATE_SUCCESS;
+    return UPDATE_FAILED;
+
+}