Login background function ideas for PHP development

The realization of the function requires the concatenation of PHP codes. Before writing PHP code, you need to clarify your ideas, otherwise the code will not be able to start. Let's first explain the flow of ideas, as shown in the figure:

According to the idea, let’s take a look at the code:

"; echo "返回登陆页面"; } }

The first thing is to connect to the database, because the login account and password are all in the database, and then start to check whether the account password verification code has been entered. judge. Then use the sql statement to query the database to see if the entered value exists in the database. If

exists and is correct, you can log in successfully. Otherwise, "Account or password error" is output and you log in again.