Debugging Summary
There is a great chance that, you might have encountered this issue multiple times in your work. This issue occurred to me most of times due to the incorrectly entering user name or password. Though this is one of the reasons, there are other many chances you might get this issue. Sometimes, it looks very similar, but when you dig deeper, you will realize multiple factors contributing to this error. This post will explain in detail, most of the common reasons and work around to fix this issue.
Possible reasons:
This is the most common reason for this error. If you entered the username or password wrongly, surely you will get this error.
Solution:
Solution for this type of error is very simple. Just enter the correct username and password. This error will be resolved. In case if you forget the password you can reset the username/password. If you forget the password for admin / root account, there are many ways to reset / recapture the root password. I will publish another post on how to reset the root password in-case if you forget root password.
MySQL provides host based restriction for user access as a security features. In our production environment, we used to restrict the access request only to the Application servers. This feature is really helpful in many production scenarios.
Solution:
When you face this type of issue, first check whether your host is allowed or not by checking the mysql.user table. If it is not defined, you can update or insert new record to mysql.user table. Generally, accessing as a root user from remote machine is disabled and it is not a best practice, because of security concerns. If you have requirements to access your server from multiple machines, give access only to those machines. It is better not to use wildcards (%) and gives universal accesses. Let me update the mysql.user table, now the demouser can access MySQL server from any host.
This type of error occurs when the user, which you are trying to access not exist on the MySQL server.
Solutions:
When you face this type of issue, just check whether the user is exists in mysql.user table or not. If the record not exists, user cannot access. If there is a requirement for that user to access, create a new user with that username.
Important points
It is not advisable to use wildcards while defining user host, try to use the exact host name.
Disable root login from remote machine.
Use proxy user concept.
There are few other concepts related with this topic and getting into details of those topics is very different scope of this article. We will look into the following related topics in the upcoming articles.
I hope this post will help for you to fix the MySQL Error Code 1045 Access denied for user in MySQL.