Uninstall of the module

The following function can be added to the file worklow.install to allow the uninstall of the module :

/**
* Implementation of hook_uninstall().
*/
function workflow_uninstall() {
// Drop database table
db_query('DROP TABLE {workflow_states}');
db_query('DROP TABLE {workflow_transitions}');
db_query('DROP TABLE {workflows}');
db_query('DROP TABLE {workflow_type_map}');
db_query('DROP TABLE {workflow_node}');
db_query('DROP TABLE {workflow_actions}');
db_query('DROP TABLE {workflow_node_history}');
db_query('DROP TABLE {workflow_scheduled_transition}');
db_query('DROP TABLE {workflow_node_history}');

// Delete variables
}

and the following one in the file workflow_access.install :

/**
* Implementation of hook_uninstall().
*/
function workflow_access_uninstall() {
// Drop database table
db_query('DROP TABLE {workflow_access}');

// Delete variables
}

Without this, the tables are not deleted even if you uninstall the module