diff --git a/db/zm_create.sql.in b/db/zm_create.sql.in
index 8cbd7866d..fc1a6a552 100644
--- a/db/zm_create.sql.in
+++ b/db/zm_create.sql.in
@@ -337,6 +337,7 @@ CREATE TABLE `Groups` (
   `Id` int(10) unsigned NOT NULL auto_increment,
   `Name` varchar(64) NOT NULL default '',
   `ParentId` int(10) unsigned,
+  FOREIGN KEY (`ParentId`) REFERENCES `Groups` (`Id`) ON DELETE CASCADE,
   PRIMARY KEY (`Id`)
 ) ENGINE=@ZM_MYSQL_ENGINE@;
 
@@ -348,7 +349,9 @@ DROP TABLE IF EXISTS `Groups_Monitors`;
 CREATE TABLE `Groups_Monitors` (
     `Id` INT(10) unsigned NOT NULL auto_increment,
     `GroupId` int(10) unsigned NOT NULL,
+    FOREIGN KEY (`GroupId`) REFERENCES `Groups` (`Id`) ON DELETE CASCADE,
     `MonitorId` int(10) unsigned NOT NULL,
+    FOREIGN KEY (`MonitorId`) REFERENCES `Monitors` (`Id`) ON DELETE CASCADE,
     PRIMARY KEY (`Id`)
 ) ENGINE=@ZM_MYSQL_ENGINE@;
 
diff --git a/db/zm_update-1.35.15.sql b/db/zm_update-1.35.15.sql
index 040e8d706..65f4e5426 100644
--- a/db/zm_update-1.35.15.sql
+++ b/db/zm_update-1.35.15.sql
@@ -10,3 +10,61 @@ This will only work if they havn't modified the stock filter .
 This is important to prevent SQL Errors inserting into Frames table if PurgeWhenFull deletes in-progress events.
  */
 UPDATE Filters SET Query_json='{"sort_field":"Id","terms":[{"val":0,"attr":"Archived","op":"="},{"cnj":"and","val":95,"attr":"DiskPercent","op":">="},{"cnj":"and","obr":"0","attr":"EndDateTime","op":"IS NOT","val":"NULL","cbr":"0"}],"limit":100,"sort_asc":1}' WHERE Query_json='{"sort_field":"Id","terms":[{"val":0,"attr":"Archived","op":"="},{"cnj":"and","val":95,"attr":"DiskPercent","op":">="}],"limit":100,"sort_asc":1}';
+
+/* Add FOREIGN KEYS After deleting lost records */
+set @exist := (select count(*) FROM information_schema.key_column_usage where table_name='Groups_Monitors' and column_name='GroupId' and referenced_table_name='Groups' and referenced_column_name='Id');
+
+set @sqlstmt := if( @exist > 1, "SELECT 'You have more than 1 FOREIGN KEY. Please do manual cleanup'", "SELECT 'Ok'");
+set @sqlstmt := if( @exist = 1, "SELECT 'FOREIGN KEY GroupId in Groups_Monitors already exists'", @sqlstmt);
+set @sqlstmt := if( @exist = 0, "SELECT 'Adding foreign key for GroupId to Groups_Monitors'", @sqlstmt);
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+
+set @sqlstmt := if( @exist = 0, "SELECT 'Deleting unlinked Groups_Monitors'", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "DELETE FROM `Groups_Monitors` WHERE `GroupId` NOT IN (SELECT `Id` FROM `Groups`)", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "ALTER TABLE `Groups_Monitors` ADD FOREIGN KEY (`GroupId`) REFERENCES `Groups` (`Id`) ON DELETE CASCADE", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+
+/* Add FOREIGN KEYS After deleting lost records */
+set @exist := (select count(*) FROM information_schema.key_column_usage where table_name='Groups_Monitors' and column_name='MonitorId' and referenced_table_name='Monitors' and referenced_column_name='Id');
+
+set @sqlstmt := if( @exist > 1, "SELECT 'You have more than 1 FOREIGN KEY. Please do manual cleanup'", "SELECT 'Ok'");
+set @sqlstmt := if( @exist = 1, "SELECT 'FOREIGN KEY MonitorId in Groups_Monitors already exists'", @sqlstmt);
+set @sqlstmt := if( @exist = 0, "SELECT 'Adding foreign key for MonitorId to Groups_Monitors'", @sqlstmt);
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+
+set @sqlstmt := if( @exist = 0, "SELECT 'Deleting unlinked Groups_Monitors'", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "DELETE FROM `Groups_Monitors` WHERE `MonitorId` NOT IN (SELECT `Id` FROM `Monitors`)", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "ALTER TABLE `Groups_Monitors` ADD FOREIGN KEY (`MonitorId`) REFERENCES `Monitors` (`Id`) ON DELETE CASCADE", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+
+/* Add FOREIGN KEYS After deleting lost records */
+set @exist := (select count(*) FROM information_schema.key_column_usage where table_name='Groups' and column_name='ParentId' and referenced_table_name='Groups' and referenced_column_name='Id');
+
+set @sqlstmt := if( @exist > 1, "SELECT 'You have more than 1 FOREIGN KEY. Please do manual cleanup'", "SELECT 'Ok'");
+set @sqlstmt := if( @exist = 1, "SELECT 'FOREIGN KEY ParentId in Groups already exists'", @sqlstmt);
+set @sqlstmt := if( @exist = 0, "SELECT 'Adding foreign key for ParentId to Groups'", @sqlstmt);
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+
+set @sqlstmt := if( @exist = 0, "SELECT 'Deleting unlinked Groups'", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "UPDATE `Groups` SET `ParentId` = NULL WHERE (ParentId IS NOT NULL) and ParentId NOT IN (SELECT * FROM(SELECT Id FROM `Groups`)tblTmp)", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+set @sqlstmt := if( @exist = 0, "ALTER TABLE `Groups` ADD FOREIGN KEY (ParentId) REFERENCES `Groups` (Id) ON DELETE CASCADE", "SELECT '.'");
+PREPARE stmt FROM @sqlstmt;
+EXECUTE stmt;
+