MySQL database users can be granted a range of privileges to restrict or grant access to a given database. Typical privileges include INSERT, UPDATE, SELECT, DELETE amongst others that represent actions or queries that a user might run against a database. The way that some people use these privileges, is to restrict DELETE or other potentially harmful queries to a specific scope or method of access. That said, for most modern web applications, you will need to grant 'all privileges' to a database user to ensure that the user is able to connect to and manipulate the database in a way that the application is expecting. Creating a post in WordPress for example would involve SELECT and INSERT queries, or removing a plugin might involve DELETE and UPDATE queries.
If you haven't already created a MySQL database, please read the article here Creating MySQL Databases and Users
To access the MySQL user privileges section log-in to cPanel, and then click MySQL Databases
Then, scroll down and find where it says Add User to Database
Select the specific user from the User drop down
Then select the database you want to grant or adjust privileges on in the Database drop down
Click the Add button and then you can mange the privileges granted to that specific user on that specific database.
Updated 7 months ago