How to manage permissions

How to implement the permission management module, set a permission management field in the database to 2 by default, the administrator wants to set 1, how to set the administrator, how can I determine that the login is an administrator? can the administrator modify the user name and password ?, The modification should be feasible. First, you can set the administrator's session as the default during login, and then determine if the modification is feasible ?, You can set the default value. If yes. After submission, determine the management permission
How to implement the management permission module, set a field for management permission in the database to 2 by default, the administrator wants to set it to 1, how to set the administrator, and how to determine whether the login is an administrator, can the administrator modify the user name and password?

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The modification should be feasible. First, you can set the administrator's session as the default during login, and then determine if the modification is feasible?
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You can set the default value. If yes. After the submission, you just need to judge.