删除sequelize迁移中的约束 [英] Remove constraints in sequelize migration

问题描述

我通过独特的约束/＃changecolumntablename-attributename-datatypeoroptionsrel =nofollow> migrations.changeColumn 函数。

I'm adding a unique constraint in a migration via the migrations.changeColumn function.

添加约束可以工作，但由于您需要提供向后迁移，删除它以相同的方式不。在向后迁移时不会给出任何错误，但是再次应用向前迁移结果可能未处理的SequelizeDatabaseError：关系myAttribute_unique_idx已存在。

Adding the constraint works, but since you need to provide a "backwards migration", removing it the same way does not. It doesn't give any errors when migrating backwards, but again applying the forward migration results in Possibly unhandled SequelizeDatabaseError: relation "myAttribute_unique_idx" already exists.

（使用的数据库是postgres）

(The used database is postgres)

module.exports = {
  up: function (migration, DataTypes, done) {
    migration.changeColumn(
      'Users',
      'myAttribute',
      {
        type: DataTypes.STRING,
        unique: true                 // ADDING constraint works
      }
    ).done(done);
  },

  down: function (migration, DataTypes, done) {
    migration.changeColumn(
      'Users',
      'myAttribute',
      {
        type: DataTypes.STRING,
        unique: false                // REMOVING does not
      }
    ).done(done);
  }
};

我也尝试使用 removeIndex

migration.removeIndex('Users', 'myAttribute_unique_idx').done(done);

但是在还原迁移时会出现以下错误：

But it gives the following error when reverting the migration:

Possibly unhandled SequelizeDatabaseError: cannot drop index "myAttribute_unique_idx" because constraint myAttribute_unique_idx on table "Users" requires it

推荐答案

不幸的是sequelize没有内置的迁移方法来删除约束。这是为什么在删除键之前，您需要进行原始查询。

Unfortunately sequelize doesn't have a builtin migration method to remove constraint. That is why before removing key you need to make a raw query.

down: function (migration, DataTypes) {
  migration.sequelize.query(
    'ALTER TABLE Users DROP CONSTRAINT myAttribute_unique_idx;'
  );
  migration.removeIndex('Users', 'myAttribute_unique_idx');

  return;
}

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