Php cannot use localhost to connect to the mysql server

Php cannot use localhost to connect to the mysql server. mysql is installed in redhat. in the mysql console, you can use localhost to connect to the server. However, when you connect to the server in php, you cannot connect to the server using 127.0.0.1, I checked the hosts file and found that there are 127.0.0.1 and localhost corresponding to which man knows what is going on. it is not because php cannot use localhost to connect to the mysql server.
Mysql is installed in redhat. you can use localhost to connect to the mysql console, but it cannot be connected in php. you can use 127.0.0.1 to connect to and view the hosts file, it is found that there are 127.0.0.1 and localhost mappings.

Which of the following heroes knows what is going on?

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Did you set the site to http: // 127.0.0.1 when creating the site?
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Let's see how your mysql is configured,
Check whether/usr/local/mysql/var/mysql. sock exists after mysql is started.
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Description
A frequent error message received ed when using the mysql command line utility is: Can't connect to local MySQL server through socket '/tmp/mysql. sock 'While this error message can be frustrating, the solution is simple.

Directions
When connecting to a MySQL server located on the local system, the mysql client connects thorugh a local file called a socket instead of connecting to the localhost loopback address 127.0.0.1. for the mysql client, the default location of this socket file is/tmp/mysql. sock. however, for a variety of reasons, using MySQL installations place this socket file somewhere else like/var/lib/mysql. sock.

While it is possible to make this work by specifying the socket file directly in the mysql client command

Mysql -- socket =/var/lib/mysql. sock...


It is painful to type this in every time. if you must do so this way (because you don't have permissions to the file in the solution below), you cocould create an alias in your shell to make this work

(Like alias mysql = "mysql -- socket =/var/lib/mysql. sock" depending on your shell ).

To make your life easier, you can make a simple change to the MySQL configuration file/etc/my. cnf that will permanently set the socket file used by the mysql client. after making a backup copy of/etc/my. cnf, open it in your favorite editor. the file is divided into sections such

[Mysqld]
Datadir =/usr/local/mysql/data
Socket =/var/lib/mysql. sock

[Mysql. server]
User = mysql
Basedir =/usr/local/mysql

If there is not currently a section called [client], add one at the bottom of the file and copy the socket = line under the [mysqld] section such:

[Client]
Socket =/var/lib/mysql. sock

If there is already a [client] section in the my. cnf file, add or edit the socket line as appropriate. you won't need to restart your server or any other processes. subsequent uses of the mysql client will use the proper socket file.