小编emp*_*r_c的帖子

type="text/babel" 的外部脚本不起作用

为什么 type="text/babel" 的外部脚本在 ReactJS 中不起作用？我将index.html和foo.js放在同一个文件夹中。使用 Google Chrome 打开 index.html 文件后没有任何显示

索引.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8"/>
        <title>ReactJS</title>
        <script src="https://unpkg.com/react@17/umd/react.development.js"></script>
        <script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
        <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
        <script type="text/babel" src="foo.js"></script>
    </head>
    <body>

        <div id="root"></div>
        
    </body>
</html>

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foo.js

ReactDOM.render(
  <h1>Hello World</h1>,
  document.getElementById('root')
);

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reactjs babeljs react-dom

emp*_*r_c

2022 10-14

5
推荐指数

1
解决办法

2848
查看次数

错误代码：1822。添加外键约束失败。引用表“employees”中缺少约束“projects_ibfk_1”的索引

CREATE DATABASE employeeDB;
USE employeeDB;

CREATE TABLE employees(
    employeeid NUMERIC(9),
    firstname VARCHAR(10),
    lastname VARCHAR(20),
    deptCode CHAR(5),
    salary NUMERIC(9, 2),
    PRIMARY KEY (employeeid)
);

CREATE TABLE projects(
    projectid CHAR(8),
    deptcode CHAR(5),
    description VARCHAR(200),
    startdate DATE,
    stopdate DATE,
    revenue NUMERIC(12, 2),
    PRIMARY KEY (projectid),
    FOREIGN KEY (deptcode) REFERENCES employees(deptCode)
);

CREATE TABLE departments(
    code CHAR(5),
    name VARCHAR(5),
    managerid NUMERIC(9),
    subdeptof CHAR(5),
    PRIMARY KEY (code),
    FOREIGN KEY (managerid) REFERENCES employees(employeeid),
    FOREIGN KEY (subdeptof) REFERENCES projects(deptcode)
);

ALTER TABLE employees ADD FOREIGN KEY (deptCode) …

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mysql sql constraints foreign-keys error-code

emp*_*r_c

lucky-day

3
推荐指数

1
解决办法

1万
查看次数