openlayer ol-hashed报错Provider already registered using the same name: center

这个错误通常出现在使用OpenLayers时，由于重复注册了同名的组件导致的。在OpenLayers中，注册一个组件时需要给它指定一个唯一的名称，如果已经存在同名的组件，就会出现这个错误。

根据错误提示信息，可能是由于注册了名为"center"的组件导致的。您可以检查代码中是否存在重复注册"center"组件的情况，并尝试修改组件的名称或者删除重复的注册代码，以解决这个问题。

相关问题

openlayer ol-hashed

现在我理解了您的问题。"ol-hashed"是OpenLayers中的一个术语，指的是在URL中添加哈希值来记录地图状态的技术。这个哈希值通常用于存储地图的缩放级别、中心点和图层状态等信息，以便在用户刷新页面或者分享链接时可以恢复之前的地图状态。

OpenLayers提供了一个名为ol-hashed的模块，可以轻松地实现地图状态的哈希记录和恢复。使用ol-hashed模块，您只需要将其导入到您的代码中，并在创建地图实例时设置相应的选项即可实现哈希记录和恢复功能。

mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 1049 (42000): Unknown database 'parking_guidance'

The warning message you're seeing is a standard security concern when using MySQL through a command-line interface, such as `mysql` or `mysqladmin`. It's advising that providing a password directly on the command line can be less secure because anyone monitoring your terminal session could potentially see it. For better protection, it's recommended to use tools like `mysql_secure_installation` or configuration files with hashed passwords.

The error message `ERROR 1049 (42000): Unknown database 'parking_guidance'` indicates that MySQL cannot find the database you are trying to access. Here's what you can do to resolve this issue:

1. **Check if the database exists:** Use the `SHOW DATABASES;` command to ensure that the 'parking_guidance' database is indeed not present in your current setup.

2. **Create the database:** If it doesn't exist, run the following command to create it:

   CREATE DATABASE parking_guidance;

3. **Grant privileges:** If you have not already done so, you'll need to grant privileges to your user account to access this new database. For example:

   GRANT ALL PRIVILEGES ON parking_guidance.* TO 'your_username'@'localhost' IDENTIFIED BY 'your_password';

Replace 'your_username' and 'your_password' with your actual MySQL credentials.

4. **Switch to the new database:** After granting privileges, use `USE parking_guidance;` to switch to the newly created database.

5. **Confirm connection:** Double-check that you can connect to the 'parking_guidance' database without any errors by running a simple query.

If you've already created the database and granted privileges, check for typos in the database name or user credentials. Make sure they match exactly as you specified them.