正确删除并创建带有sequelize的ENUM？

Question

如何在迁移中正确删除然后重新创建用于Postgres的sequelize的ENUM类型？例如,此迁移不会丢弃enum_Users_status枚举...因此,在创建status值之后重新创建/更改值的任何尝试都将失败.

module.exports = {
    up: function (queryInterface, DataTypes) {
        queryInterface.createTable('Users', {
            //...
            status: {
                type: DataTypes.ENUM,
                values: [
                    'online',
                    'offline',
                ],
                defaultValue: 'online'
            }
            //...
        })
    },

    down: function (queryInterface) {
        queryInterface.dropTable('Users')
    },
}

最终我确实设法删除了内部的枚举类型down,但随后up迁移(应该status从头创建这个枚举)失败,说public.enum_Users_status枚举类型之类的东西不存在.

Answer 1

手动删除 ENUMdown对我来说效果很好。

module.exports = {
    up: function (queryInterface, DataTypes) {
        queryInterface.createTable('Users', {
            //...
            status: {
                type: DataTypes.ENUM,
                values: [
                    'online',
                    'offline',
                ],
                defaultValue: 'online'
            }
            //...
        })
    },

    down: function (queryInterface) {
        return queryInterface.sequelize.transaction(t => {
            return Promise.all([
                queryInterface.dropTable('Users'),
                queryInterface.sequelize.query('DROP TYPE IF EXISTS "enum_Users_status";'),
            ]);
        });
    }
};

Answer 2

更新：到目前为止，我已经在三个项目中使用了它，所以我决定创建一个npm模块：https ://www.npmjs.com/package/replace-enum-postgresql 。

我制作了一个实用程序来执行此操作，希望对您有所帮助。

utils/replace_enum.js：

'use strict';

/**
 * Since PostgreSQL still does not support remove values from an ENUM,
 * the workaround is to create a new ENUM with the new values and use it
 * to replace the other.
 *
 * @param {String} tableName
 * @param {String} columnName
 * @param {String} defaultValue
 * @param {Array}  newValues
 * @param {Object} queryInterface
 * @param {String} enumName - Optional.
 *
 * @return {Promise}
 */
module.exports = function replaceEnum({
  tableName,
  columnName,
  defaultValue,
  newValues,
  queryInterface,
  enumName = `enum_${tableName}_${columnName}`
}) {
  const newEnumName = `${enumName}_new`;

  return queryInterface.sequelize.transaction((t) => {
    // Create a copy of the type
    return queryInterface.sequelize.query(`
      CREATE TYPE ${newEnumName}
        AS ENUM ('${newValues.join('\', \'')}')
    `, { transaction: t })
      // Drop default value (ALTER COLUMN cannot cast default values)
      .then(() => queryInterface.sequelize.query(`
        ALTER TABLE ${tableName}
          ALTER COLUMN ${columnName}
            DROP DEFAULT
      `, { transaction: t }))
      // Change column type to the new ENUM TYPE
      .then(() => queryInterface.sequelize.query(`
        ALTER TABLE ${tableName}
          ALTER COLUMN ${columnName}
            TYPE ${newEnumName}
            USING (${columnName}::text::${newEnumName})
      `, { transaction: t }))
      // Drop old ENUM
      .then(() => queryInterface.sequelize.query(`
        DROP TYPE ${enumName}
      `, { transaction: t }))
      // Rename new ENUM name
      .then(() => queryInterface.sequelize.query(`
        ALTER TYPE ${newEnumName}
          RENAME TO ${enumName}
      `, { transaction: t }))
      .then(() => queryInterface.sequelize.query(`
        ALTER TABLE ${tableName}
          ALTER COLUMN ${columnName}
            SET DEFAULT '${defaultValue}'::${enumName}
      `, { transaction: t }));
  });
}

这是我的示例迁移：

'use strict';

const replaceEnum = require('./utils/replace_enum');

module.exports = {
  up: (queryInterface, Sequelize) => {
    return replaceEnum({
      tableName: 'invoices',
      columnName: 'state',
      enumName: 'enum_invoices_state',
      defaultValue: 'created',
      newValues: ['archived', 'created', 'paid'],
      queryInterface
    });
  },

  down: (queryInterface, Sequelize) => {
    return replaceEnum({
      tableName: 'invoices',
      columnName: 'state',
      enumName: 'enum_invoices_state',
      defaultValue: 'draft',
      newValues: ['archived', 'draft', 'paid', 'sent'],
      queryInterface
    });
  }
};

Answer 3

如果要更改/编辑，请输入枚举而不丢失数据。这是我的迁移代码。希望它会有所帮助。

queryInterface.changeColumn(
  'table_name',
  'Column_name',
  {
    type: Sequelize.TEXT,
  },
),
queryInterface.sequelize.query('drop type enum_tableName_columnName;')
.then(() => queryInterface.changeColumn(
  'table_name',
  'column_name',
  {
    type: Sequelize.ENUM('value1','value2'),
  },
)),