Question

我正在尝试在日期列的现有表（Postgres）上创建索引，以便首先获取最新的帖子

模型文件feeditem.js

module.exports = (sequelize, DataTypes) => {
  const FeedItem = sequelize.define('FeedItem', {
    feedItemId: {
      //...
    },
    pubdate: {
      allowNull: false,
      type: DataTypes.DATE,
      validate: {
        isDate: true,
        notEmpty: true,
      },
    },
    link: {
      //...
    },
    title: {
      //...
    },
    description: {
      //...
    },
    summary: {
      //...
    },
    author: {
      //...
    },
    hash: {
      //...
    },
  }, {
    timestamps: false,
    underscored: true,
    indexes: [
      {
        fields: [{ attribute: 'pubdate', order: 'DESC' }],
        unique: false,
      },
    ],
  });

  FeedItem.associate = (models) => {
    // associations can be defined here
    //...
  };
  return FeedItem;
};

迁移文件create-feed-item.js

module.exports = {
  up: (queryInterface, Sequelize) => queryInterface.createTable('feed_items', {
    feed_item_id: {
      allowNull: false,
      autoIncrement: true,
      primaryKey: true,
      type: Sequelize.INTEGER,
    },
    pubdate: {
      allowNull: false,
      type: Sequelize.DATE,
    },
    link: {
      allowNull: false,
      type: Sequelize.STRING,
    },
    title: {
      allowNull: false,
      type: Sequelize.STRING,
    },
    description: {
      type: Sequelize.TEXT,
    },
    summary: {
      type: Sequelize.TEXT,
    },
    author: {
      type: Sequelize.STRING,
    },
    hash: {
      allowNull: false,
      type: Sequelize.UUID,
      unique: true,
    },
  }),
  // eslint-disable-next-line no-unused-vars
  down: (queryInterface, Sequelize) => queryInterface.dropTable('feed_items'),
};

迁移文件add-index.js

module.exports = {
  /*
    Add altering commands here.
    Return a promise to correctly handle asynchronicity.
    Example:
    return queryInterface.createTable('users', { id: Sequelize.INTEGER });
  */
  // eslint-disable-next-line no-unused-vars
  up: (queryInterface, Sequelize) => queryInterface.addIndex('feed_items', ['pubdate'], {
    fields: [{
      attribute: 'pubdate', order: 'DESC',
    }],
    unique: false,
    name: 'feed_items_pubdate_index',
  }),
  /*
    Add reverting commands here.
    Return a promise to correctly handle asynchronicity.
    Example:
    return queryInterface.dropTable('users');
  */
  // eslint-disable-next-line no-unused-vars
  down: (queryInterface, Sequelize) => queryInterface.removeIndex('feed_items', 'feed_items_pubdate_index'),
};

迁移以完美的顺序运行，首先创建表，然后添加索引。启用了日志记录，当我检查日志时

预期：它应该在pubdate上创建DESC索引，

CREATE INDEX "feed_items_pubdate_index" ON "feed_items" ("pubdate" DESC)

实际输出

Executing (default): CREATE INDEX "feed_items_pubdate_index" ON "feed_items" ("pubdate")

有什么想法吗？

Answer 1

您的问题仍然相关，因为它没有记录。

按降序定义索引的正确方法是在 fields 参数中扩展定义。

因此迁移文件 add-index.js 应如下所示：

module.exports = {
  ...
  up: (queryInterface, Sequelize) => queryInterface.addIndex(
    'feed_items', 
    [{
      attribute: 'pubdate', order: 'DESC',
    }], 
    {
      unique: false,
      name: 'feed_items_pubdate_index',
    }
  ),
  ...
};

已解决 issue reference。

Answer 2

使用唯一键：

'use strict';
module.exports = {
  up: (queryInterface, Sequelize) => {
    return queryInterface.createTable('Users', {
      id: {
        allowNull: false,
        autoIncrement: true,
        primaryKey: true,
        type: Sequelize.INTEGER
      },
      name: {
        allowNull: true,
        type: Sequelize.STRING
      },
      order: {
        allowNull: false,
        type: Sequelize.INTEGER
      },
      createdAt: {
        allowNull: false,
        type: Sequelize.DATE
      },
      updatedAt: {
        allowNull: false,
        type: Sequelize.DATE
      }
    },
    {
      uniqueKeys: {
        actions_unique: {
          fields: ["name", "order"],
        },
      },
    }
    );
  },
  down: (queryInterface, Sequelize) => {
    return queryInterface.dropTable('Users');
  }
};

Sequelize Migration addIndex不按降序添加索引

2 个答案: