-- A physical patch panel may continue the labelling from the preceding panel.
ALTER TABLE locations_cross_fields
    ADD COLUMN IF NOT EXISTS start_port_number INTEGER NOT NULL DEFAULT 1;

ALTER TABLE locations_cross_fields
    DROP CONSTRAINT IF EXISTS locations_cross_fields_start_port_number_check;
ALTER TABLE locations_cross_fields
    ADD CONSTRAINT locations_cross_fields_start_port_number_check
    CHECK (start_port_number BETWEEN 1 AND 9999);