CREATE OR REPLACE TRIGGER trg_update_park_capacity before
INSERT OR DELETE ON parkingslot
    FOR each ROW
DECLARE
    eletric_cap   park.eletric_capacity%TYPE;
    non_eletric_cap   park.non_eletric_capacity%TYPE;
    pa park.id_park%TYPE;
    btype bicycletype.id_bicycle_type%TYPE;
BEGIN
    IF inserting THEN
        pa :=:NEW.id_park;
        btype :=:NEW.id_bicycle_type;
        IF btype = 3 THEN
            SELECT eletric_capacity
            INTO eletric_cap
            FROM park
            WHERE id_park = pa;
            eletric_cap:= eletric_cap + 1;
        ELSE
            SELECT non_eletric_capacity
            INTO non_eletric_cap
            FROM park
            WHERE id_park = pa;
            non_eletric_cap:= non_eletric_cap + 1;
        END IF;
    ELSE
        pa :=:NEW.id_park;
        btype :=:NEW.id_bicycle_type;
        btype :=:NEW.id_bicycle_type;
        IF btype = 3 THEN
            SELECT eletric_capacity
            INTO eletric_cap
            FROM park
            WHERE id_park = pa;
            eletric_cap:= eletric_cap - 1;
        ELSE
            SELECT non_eletric_capacity
            INTO non_eletric_cap
            FROM park
            WHERE id_park = pa;
            non_eletric_cap:= non_eletric_cap - 1;
        END IF;
    END IF;
    UPDATE park
    SET eletric_capacity = eletric_cap, non_eletric_capacity = non_eletric_cap
    WHERE id_park = pa;
END trg_update_park_capacity;