GUACAMOLE-52: Foreign keys in history table should be ON DELETE SET NULL. For sake of context, always store username and connection name in history table.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/schema/001-create-schema.sql

@@ -274,11 +274,13 @@ CREATE INDEX ON guacamole_user_permission(user_id);
 
 CREATE TABLE guacamole_connection_history (
 
-  history_id    serial      NOT NULL,
-  user_id       integer     NOT NULL,
-  connection_id integer     NOT NULL,
-  start_date    timestamptz NOT NULL,
-  end_date      timestamptz DEFAULT NULL,
+  history_id      serial       NOT NULL,
+  user_id         integer      DEFAULT NULL,
+  username        varchar(128) NOT NULL,
+  connection_id   integer      DEFAULT NULL,
+  connection_name varchar(128) NOT NULL,
+  start_date      timestamptz  NOT NULL,
+  end_date        timestamptz  DEFAULT NULL,
 
   PRIMARY KEY (history_id),
 

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-postgresql/schema/upgrade/upgrade-pre-0.9.10.sql

@@ -0,0 +1,90 @@
+--
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--   http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing,
+-- software distributed under the License is distributed on an
+-- "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+-- KIND, either express or implied.  See the License for the
+-- specific language governing permissions and limitations
+-- under the License.
+--
+
+--
+-- User and connection IDs within history table can now be null
+--
+
+ALTER TABLE guacamole_connection_history
+    ALTER COLUMN user_id SET DEFAULT NULL,
+    ALTER COLUMN user_id DROP NOT NULL;
+
+ALTER TABLE guacamole_connection_history
+    ALTER COLUMN connection_id SET DEFAULT NULL,
+    ALTER COLUMN connection_id DROP NOT NULL;
+
+--
+-- Add new username and connection_name columns to history table
+--
+
+ALTER TABLE guacamole_connection_history
+    ADD COLUMN username varchar(128);
+
+ALTER TABLE guacamole_connection_history
+    ADD COLUMN connection_name varchar(128);
+
+--
+-- Populate new name columns by joining corresponding tables
+--
+
+UPDATE guacamole_connection_history
+    SET username = guacamole_user.username
+    FROM guacamole_user
+    WHERE guacamole_user.user_id = guacamole_connection_history.user_id;
+
+UPDATE guacamole_connection_history
+    SET connection_name = guacamole_connection.connection_name
+    FROM guacamole_connection
+    WHERE guacamole_connection.connection_id =
+        guacamole_connection_history.connection_id;
+
+--
+-- Set NOT NULL now that the column is fully populated
+--
+
+ALTER TABLE guacamole_connection_history
+    ALTER COLUMN username SET NOT NULL;
+
+ALTER TABLE guacamole_connection_history
+    ALTER COLUMN connection_name SET NOT NULL;
+
+--
+-- Remove old foreign key constraints with ON DELETE CASCADE
+--
+
+ALTER TABLE guacamole_connection_history
+    DROP CONSTRAINT guacamole_connection_history_ibfk_1;
+
+ALTER TABLE guacamole_connection_history
+    DROP CONSTRAINT guacamole_connection_history_ibfk_2;
+
+--
+-- Recreate foreign key constraints with ON DELETE SET NULL
+--
+
+ALTER TABLE guacamole_connection_history
+    ADD CONSTRAINT guacamole_connection_history_ibfk_1
+    FOREIGN KEY (user_id)
+    REFERENCES guacamole_user (user_id) ON DELETE SET NULL;
+
+ALTER TABLE guacamole_connection_history
+    ADD CONSTRAINT guacamole_connection_history_ibfk_2
+    FOREIGN KEY (connection_id)
+    REFERENCES guacamole_connection (connection_id) ON DELETE SET NULL;
+