Someone

 create table event_parameters (
    id INTEGER DEFAULT nextval('opennmsNxtId') NOT NULL,
    eventId INTEGER NOT NULL,
    name text(31)  NOT NULL,
    value text(255)  NOT NULL,
    type varchar(31)  NOT NULL,
    encoding varchar(31)  NOT NULL,

    CONSTRAINT event_parameters_id PRIMARY KEY (id),
    CONSTRAINT event_parameters_eventid FOREIGN KEY (eventid) REFERENCES events (eventid) ON DELETE CASCADE
)

CREATE UNIQUE INDEX event_parameters_eventid_name on event_parameters (eventid, name);
CREATE INDEX  event_parameters_value on event_parameters (value);