跨多个表的参照完整性

Question

确保输入 table 的任何数据与对应关系中的数据相匹配的最简单方法是什么？在我的例子中，我有一个体育俱乐部。玩家可以在没有团队的情况下进行运动。我想强制玩家在加入团队之前参加这项运动。

这是我的 tables:

create table IF NOT EXISTS sports (
    sport_id SERIAL,
    sport_name VARCHAR(50),
    PRIMARY KEY(sport_id)
    );

create table IF NOT EXISTS players (
    player_id SERIAL,
    player_name VARCHAR(50),
    player_phone VARCHAR(20),
    PRIMARY KEY(player_id)
    );

create table IF NOT EXISTS players_sports (
    player_id INT REFERENCES players(player_id),
    sport_id int REFERENCES sports(sport_id),
    PRIMARY KEY (player_id, sport_id)
    );

create table IF NOT EXISTS teams (
    team_name VARCHAR(50),
    sport_id INT,
    captain_id INT,
    FOREIGN KEY (sport_id, captain_id) 
        REFERENCES players_sports(sport_id, player_id),
    PRIMARY KEY (team_name, sport_id)
    );

create table IF NOT EXISTS has_players (
    team_name VARCHAR(50),
    sport_id int,
    player_id INT REFERENCES players(player_id),
    FOREIGN KEY (team_name, sport_id) 
        REFERENCES teams(team_name, sport_id),
    PRIMARY KEY(team_name, sport_id, player_id)
    );

CREATE TYPE DAY AS ENUM (
  'Monday',
  'Tuesday',
  'Wednesday',
  'Thursday',
  'Friday',
  'Saturday',
  'Sunday'
);

create table IF NOT EXISTS time_slot (
    training_id SERIAL,
    training_day DAY,
    training_time TIME,
    team_name VARCHAR(50),
    sport_id int,
    FOREIGN KEY (team_name, sport_id) 
        REFERENCES teams (team_name, sport_id),
    PRIMARY KEY (training_id)
    );

Answer 1

I want to enforce that the player plays the sport BEFORE joining a team.

像这样添加另一个 FK constraint：

CREATE TABLE IF NOT EXISTS has_players (
  team_name varchar(50)
, sport_id  int
, player_id int
, PRIMARY KEY(team_name, sport_id, player_id)
, FOREIGN KEY (team_name, sport_id)
    REFERENCES teams(team_name, sport_id)
<b>, FOREIGN KEY (player_id, sport_id)
    REFERENCES players_sports(player_id, sport_id)</b>
);

您可以在多个 FK 约束中包含相同的列（如果这是阻止您这样做的原因）。

跨多个表的参照完整性

Referential integrity across multiple tables

sql

database

postgresql

database-design

constraints