Реализация связи "многие ко многим" в БД

CREATE TABLE current_model (
    current_id serial PRIMARY KEY,
    model_name VARCHAR(256) NOT NULL UNIQUE
) WITH (
  OIDS=FALSE
);
 
CREATE TABLE kind_of_body (
    kind_of_body_id serial PRIMARY KEY,
    name_kind_of_body VARCHAR(256) NOT NULL UNIQUE
) WITH (
  OIDS=FALSE
);
 
CREATE TABLE engine (
    engine_id serial PRIMARY KEY,
    name_of_engine VARCHAR(256) NOT NULL UNIQUE,
    horsepower BIGINT
) WITH (
  OIDS=FALSE
);
 
 
CREATE TABLE color_table (
    color_id serial PRIMARY KEY,
    name_color VARCHAR(256) NOT NULL,
    isMetallic BOOLEAN NOT NULL,
    UNIQUE (name_color,isMetallic)
) WITH (
  OIDS=FALSE
);
 
CREATE TABLE transmission (
    transmission_id serial PRIMARY KEY,
    name_transmission VARCHAR(256) NOT NULL UNIQUE,
    number_of_speed BIGINT
) WITH (
  OIDS=FALSE
);
 
CREATE TABLE color_set (
    set_id serial NOT NULL,
    color_id BIGINT NOT NULL REFERENCES color_table (color_id),
    PRIMARY KEY(set_id,color_id)
) WITH (
  OIDS=FALSE
);
 
 
CREATE TABLE car_parametrs (
    model_id BIGINT REFERENCES current_model (current_id),
    engine_id BIGINT REFERENCES engine (engine_id),
    transmission_id BIGINT REFERENCES transmission (transmission_id) ,
    kind_of_body_id BIGINT REFERENCES kind_of_body (kind_of_body_id),
    set_id BIGINT,
    color_id BIGINT,
    FOREIGN KEY (set_id,color_id) REFERENCES color_set(set_id,color_id),
    PRIMARY KEY(model_id,engine_id,
    transmission_id,kind_of_body_id,set_id)
) WITH (
  OIDS=FALSE
);

CREATE TABLE SET (
    set_id serial NOT NULL
    PRIMARY KEY(set_id)
) WITH (
  OIDS=FALSE
);

CREATE TABLE color_set (
    set_id BIGINT NOT NULL REFERENCES SET (set_id),
    color_id BIGINT NOT NULL REFERENCES color_table (color_id),
    PRIMARY KEY(set_id,color_id)
) WITH (
  OIDS=FALSE
);