node.js 从 v4.0.0 开始，需要明确提供方言
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Dialect needs to be explicitly supplied as of v4.0.0
提问by shumana chowdhury
I have been working on a NodeJS project which uses PostgreSQL database. I am trying to implement migration to the database. Also, using Sequelize. After setting up the migration folder and config, it throws error while running db:migrate
我一直在研究一个使用 PostgreSQL 数据库的 NodeJS 项目。我正在尝试实现到数据库的迁移。另外，使用 Sequelize。设置迁移文件夹和配置后，运行 db:migrate 时抛出错误
The error is: "Dialect needs to be explicitly supplied as of v4.0.0"
错误是：“方言需要从 v4.0.0 开始明确提供”
回答by JPero
Solution for me was based on what I had set for my NODE_ENVvariable.
我的解决方案基于我为NODE_ENV变量设置的内容。
echo $NODE_ENV
echo $NODE_ENV
If you do not have anything set for that variable, try setting it with the following:
如果您没有为该变量设置任何内容，请尝试使用以下内容进行设置：
export NODE_ENV=development
export NODE_ENV=development
If a value ispresent, make sure you have an entry in your config file for thatvalue. For me, I like to use local. So I had to update my config to this:
如果值是存在，请确保你在你的config文件中的条目该值。对我来说，我喜欢使用local. 所以我不得不将我的配置更新为：
{
local: {
username: 'root',
password: null,
database: 'database_dev',
host: '127.0.0.1',
dialect: 'postgres'
},
development: {
username: 'root',
password: null,
database: 'database_dev',
host: '127.0.0.1',
dialect: 'postgres'
},
test: {
username: 'root',
password: null,
database: 'database_test',
host: '127.0.0.1',
dialect: 'postgres'
},
production: {
username: 'root',
password: null,
database: 'database',
host: '127.0.0.1',
dialect: 'postgres'
}
}
回答by Sourav Kumar Behura
Check the dialect once.
检查方言一次。
const Sequelize = require('sequelize');
// Option 1: Passing parameters separately
const sequelize = new Sequelize('database', 'username', 'password', {
host: 'localhost',
dialect: /* one of 'mysql' | 'mariadb' | 'postgres' | 'mssql' */
});
const Sequelize = require('sequelize');
// Option 1: Passing parameters separately
const sequelize = new Sequelize('database', 'username', 'password', {
host: 'localhost',
dialect: /* one of 'mysql' | 'mariadb' | 'postgres' | 'mssql' */
});
回答by Sergiy Voytovych
Check your config file (env names)
检查您的配置文件（环境名称）
{
development: {
username: 'root',
password: null,
database: 'database_development',
host: '127.0.0.1',
dialect: 'mysql'
},
test: {
username: 'root',
password: null,
database: 'database_test',
host: '127.0.0.1',
dialect: 'mysql'
},
production: {
username: 'root',
password: null,
database: 'database_production',
host: '127.0.0.1',
dialect: 'mysql'
}
}回答by Murat Ersin
I got same error and I saw this mistake in the code.
我遇到了同样的错误，我在代码中看到了这个错误。
title: {
type: Sequelize,
allowNull: false,
},
Changed my code with this and problem is solved:
用这个更改了我的代码，问题解决了：
title: {
type: Sequelize.STRING,
allowNull: false,
},
回答by Mark Hymanson
My issue was that I wasn't pointing to the config file properly. It said "successfully loaded" but I wasn't pointing to the right file.
我的问题是我没有正确指向配置文件。它说“成功加载”，但我没有指向正确的文件。
It should say "Loaded configuration file "[some path]/config.js"."
它应该说“加载的配置文件“[某些路径]/config.js”。
回答by Olawale Isaac
This error can also be caused if there is an error in your model schema.
如果您的模型架构中存在错误，也可能导致此错误。
I had:
我有：
middle_name: {
type: Sequelize.Sequelize,
allowNull: false,
}
middle_name: {
type: Sequelize.Sequelize,
allowNull: false,
}
Which should had been:
应该是：
middle_name: {
type: Sequelize.STRING,
allowNull: false,
}
middle_name: {
type: Sequelize.STRING,
allowNull: false,
}
回答by Napinator
did you forget to add the dialect to your config? see: http://docs.sequelizejs.com/manual/tutorial/migrations.html
您是否忘记将方言添加到您的配置中？请参阅：http: //docs.sequelizejs.com/manual/tutorial/migrations.html
回答by Delino
if you have not setup any .env variables before running your npm server
如果您在运行之前没有设置任何 .env 变量 npm server
You are likely to get that error. so each time you restart app for changes. you will have to export again
您很可能会收到该错误。所以每次你重新启动应用程序进行更改时。你将不得不再次导出
export DATABASE_URL=<your-db-url>
