如何使用sequelize.js将表的列设置为外键

问题描述

我要实现的目标是：添加新的竞赛时，我需要在表 team_comp 中创建一行，其中包含表竞争以及我根据要求发送的其他数据。我将参加很多比赛，但每个比赛都有一个属于它的team_comp。如果我删除比赛，则必须删除其team_comp行。

表格竞争：

| id  | name  | competition_teams |
|  1  |  A    |      32           |

表 team_comp ：

| id  | competition_id  | test_h |
|  3  |       32        |  1     |

在我的 models / index.js 中，我正在定义如下关联：

// Competition
db.competition.hasOne(db.competition_team,{as: 'compId',foreignKey : 'competition_id'});

// Competition Teams
db.competition_team.belongsTo(db.competition,{as: 'compTeam',foreignKey : 'competition_id',onDelete: 'CASCADE'});

这样做，我得到了错误的外键。它在表** team_comp **中创建一个指向 competion.id 的外键，而不指向 competition.competition_teams 的外键（这是我想要的）。 如何让它指向Competition.competition_teams？

这是我添加新竞赛（控制器/ Competition.js）的方式：

import db from '../models/index';
const Competition = db.competition;
const Competition_teams = db.competition_team;

// create competition
const create = (req,res) => {

    // generating a random id for the competition
    var competition_teams = Math.floor(Math.random() * 100);

    let { 
       name,test_h,} = req.body;
     
    // create new Competition
    let newCompetition = { 
      name,competition_teams // this must be also added in table team_comp,column competition_id
    }

    let newCompetitionTeams = {
      test_h
    }

    Competition.create(newCompetition)
      .then(Competition => {
        res.json({ Competition });
      })
      .catch(err => {
        console.log("Error: " + err);
        return res.status(500).json({ err });
      });

    // creating teams association    
    Competition_teams.create(newCompetitionTeams)
      .then(Competition_teams => {
        res.json({ Competition_teams });
      })
      .catch(err => {
        console.log("Error: " + err);
        return res.status(500).json({ err });
      });
}

解决方法

您需要在关联中指定sourceKey属性-如果被忽略，它将使用table + id Reference

用作源表中关联的键的属性名称。默认为源表的主键

请参见以下完整示例：

class Competition extends Sequelize.Model {
}

Competition.init({
    id: {
        primaryKey: true,type: Sequelize.INTEGER,allowNull: false
    },name: {
        type: Sequelize.STRING(36)
    },team_competition_id: {
        type: Sequelize.INTEGER,allowNull: false,}
},{
    sequelize,modelName: 'competition',tableName: 'competitions',timestamps: false
});

class Team_Competition extends Sequelize.Model {
}

Team_Competition.init({
    id: {
        primaryKey: true,},modelName: 'team_competition',tableName: 'team_competitions',timestamps: false
});

// use sourceKey here - also make sure you specify `cascade` and `hooks` property
Competition.hasOne(Team_Competition,{sourceKey: 'team_competition_id',foreignKey: 'id',onDelete: 'cascade',hooks: true});

// tests
    // create the team_competition
    const team_competition = await Team_Competition.create({
        id: 1,name: 'Team A'
    });

    // create the competition
    const competition = await Competition.create({
        id: 1,name: 'Comp A',team_competition_id: team_competition.id
    });

    // test the join
    const competitions = await Competition.findAll({
        include: [
            {
                attributes: ['id','name'],model: Team_Competition,}
        ],raw: true
    });

    // delete and verify cascade
    await competition.destroy();

将生成并执行以下SQL：

Executing (default): INSERT INTO "team_competitions" ("id","name") VALUES ($1,$2) RETURNING *;
Executing (default): INSERT INTO "competitions" ("id","name","team_competition_id") VALUES ($1,$2,$3) RETURNING *;

// query
Executing (default): SELECT "competition"."id","competition"."name","competition"."team_competition_id","team_competition"."id" AS "team_competition.id","team_competition"."name" AS "team_competition.name" FROM "competitions" AS "competition" LEFT OUTER JOIN "team_competitions" AS "team_competition" ON "competition"."team_competition_id" = "team_competition"."id";

// cascade deletes
Executing (default): DELETE FROM "team_competitions" WHERE "id" = 1
Executing (default): DELETE FROM "competitions" WHERE "id" = 1