如何在PostgreSQL HStore中限制键值对的数量/长度？

CREATE OR REPLACE FUNCTION check_hstore_length() RETURNS TRIGGER AS $$
DECLARE
    hstore_length INTEGER;
BEGIN
    hstore_length := (SELECT COUNT(*) FROM EACH(hstore(NEW.your_hstore_column)));
    IF hstore_length > 10 THEN -- 假设限制为10个键值对
        RAISE EXCEPTION 'HStore length exceeds the limit';
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER hstore_length_trigger
BEFORE INSERT OR UPDATE ON your_table
FOR EACH ROW
EXECUTE FUNCTION check_hstore_length();

CREATE OR REPLACE FUNCTION check_hstore_key_value_length() RETURNS TRIGGER AS $$
DECLARE
    max_length INTEGER := 50; -- 假设限制键和值的长度为50个字符
    key_length INTEGER;
    value_length INTEGER;
    kv RECORD;
BEGIN
    FOREACH kv IN ARRAY hstore_to_array(NEW.your_hstore_column) LOOP
        key_length := length(kv.key);
        value_length := length(kv.value);
        IF key_length > max_length OR value_length > max_length THEN
            RAISE EXCEPTION 'HStore key or value length exceeds the limit';
        END IF;
    END LOOP;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER hstore_key_value_length_trigger
BEFORE INSERT OR UPDATE ON your_table
FOR EACH ROW
EXECUTE FUNCTION check_hstore_key_value_length();