Sequelize不会创建外键作为约束

问题描述

我们正在尝试使用Sequelize在PostgreSQL内部自动创建表。不幸的是，它没有创建外键作为约束。这是我的一个模型的示例：

We're trying to create tables automatically inside PostgreSQL using Sequelize. Unfortunately, it doesn't create the foreign keys as constraints. Here is an example of one of my models:

module.exports = function(schema, DataTypes) {

    var definition = {
        id: {
            type: DataTypes.INTEGER,
            primaryKey: true,
            autoIncrement: true
        },
        deal_id: {
            type: DataTypes.INTEGER
        },
        image: DataTypes.STRING,
    };


    var image = schema.define('Image', definition, {
        tableName: 'images', // this will define the table's name
        timestamps: false, // this will deactivate the timestamp columns
        syncOnAssociation: true,

        classMethods: {
            getDefinition: function() {
                return definition;
            },
            associate: function(_models) {
                image.belongsTo(_models.Product, {
                    foreignKey: 'deal_id'
                });
            }
        }
    });

    return image;
};

我做错了吗？

推荐答案

首先，ORM在内部处理这种事情而不是通过在数据库中使用外键约束来处理这种情况并不少见。

First, it's not uncommon for ORMs to handle this kind of thing internally rather than by using foreign key constraints in the database.

其次，ORM要求关联语句的 pair 来触发您可能期望的所有内部处理并不少见。

Second, it's not uncommon for ORMs to require a pair of association statements to trigger all the internal handling you might expect.

var Task = this.sequelize.define('Task', { title: Sequelize.STRING })
  , User = this.sequelize.define('User', { username: Sequelize.STRING })

User.hasMany(Task)
Task.belongsTo(User)

最后，Sequelize实际上会将外键声明写入数据库，但前提是您还必须使用 onUpdate 或<$ c声明某种操作（或不作为） $ c> onDelete 。

Finally, Sequelize will actually write foreign key declarations into the database, but only if you also declare some kind of action (or inaction) with onUpdate or onDelete.

User.hasMany(Task, { onDelete: 'SET NULL', onUpdate: 'CASCADE' })

CREATE TABLE IF NOT EXISTS `Task` (
  `id` INTEGER PRIMARY KEY,
  `title` VARCHAR(255),
  `user_id` INTEGER REFERENCES `User` (`id`) ON DELETE SET NULL ON UPDATE CASCADE
);

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