The actions associated to conditions of the filtering system.
> Columns
expr_id: integer (not null)
Expression to which the action is connected. This is a
foreign key to filter_expr.exr_id.
action_order: smallint
Order of the action in the list of actions connected
to the expression.
action_type: varchar(100)
The kind of the action. Possible values are:
action_arg: text
A string that qualifies the action and whose interpretation
depends on action_type. Possible values are: