tracim/doc/database/pod-upgrade-0.2.0_to_0.3.0.sql

-- move table
ALTER TABLE pod_nodes RENAME TO pod_nodes_history;

-- add uuid index
-- drop primary key
-- new primary key
CREATE SEQUENCE pod_nodes_version_id_sequence;
ALTER TABLE pod_nodes_history
    DROP CONSTRAINT pod_nodes_pk CASCADE,
    ADD COLUMN version_id INTEGER PRIMARY KEY DEFAULT nextval('pod_nodes_version_id_sequence');

-- create view
CREATE OR REPLACE VIEW pod_nodes AS
    SELECT DISTINCT ON (node_id) node_id, parent_id, node_order, node_type, created_at, updated_at, 
        data_label, data_content, data_datetime, node_status, data_reminder_datetime, 
        data_file_name, data_file_content, data_file_mime_type, parent_tree_path, 
        node_depth, owner_id
    FROM pod_nodes_history
    ORDER BY node_id, updated_at DESC;

CREATE OR REPLACE RULE pod_insert_new_node AS ON INSERT
TO pod_nodes
DO INSTEAD INSERT INTO pod_nodes_history (node_id, parent_id, node_order, node_type, created_at, updated_at, 
       data_label, data_content, data_datetime, node_status, data_reminder_datetime, 
       data_file_name, data_file_content, data_file_mime_type, parent_tree_path, 
       node_depth, owner_id, version_id) VALUES (nextval('pod_nodes__node_id__sequence'), NEW.parent_id, NEW.node_order, NEW.node_type, NEW.created_at, NEW.updated_at, NEW.data_label, NEW.data_content, NEW.data_datetime, NEW.node_status, NEW.data_reminder_datetime, NEW.data_file_name, NEW.data_file_content, NEW.data_file_mime_type, NEW.parent_tree_path, NEW.node_depth, NEW.owner_id, nextval('pod_nodes_version_id_sequence'))
RETURNING node_id, parent_id, node_order, node_type, created_at, updated_at, 
       data_label, data_content, data_datetime, node_status, data_reminder_datetime, 
       data_file_name, data_file_content, data_file_mime_type, parent_tree_path, 
       node_depth, owner_id;

CREATE OR REPLACE FUNCTION pod_update_node() RETURNS trigger AS $$
BEGIN
INSERT INTO pod_nodes_history (node_id, parent_id, node_order, node_type, created_at, updated_at, 
       data_label, data_content, data_datetime, node_status, data_reminder_datetime, 
       data_file_name, data_file_content, data_file_mime_type, parent_tree_path, 
       node_depth, owner_id, version_id) VALUES (NEW.node_id, NEW.parent_id, NEW.node_order, NEW.node_type, NEW.created_at, NEW.updated_at, NEW.data_label, NEW.data_content, NEW.data_datetime, NEW.node_status, NEW.data_reminder_datetime, NEW.data_file_name, NEW.data_file_content, NEW.data_file_mime_type, NEW.parent_tree_path, NEW.node_depth, NEW.owner_id, nextval('pod_nodes_version_id_sequence'));
return new;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER pod_update_node_tg INSTEAD OF UPDATE ON pod_nodes FOR EACH ROW EXECUTE PROCEDURE pod_update_node();