如何创建数据库的唯一用户名？[重复]

Question

我有一个字段名为

用户名：uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu。

这个我想在php和mysqli中执行

Answer 1

只需将其标记为独特。

CREATE TABLE User
(
P_Id int NOT NULL UNIQUE,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255)
)

在PHP脚本中，执行如下操作：

$query = mysqli_query($con, "SELECT id FROM user WHERE username='$username'");

if(mysqli_num_rows($query) > 0){

    echo "Username already exists";
}else{
    // do something
    if (!mysqli_query($con,$query))
    {
        die('Error: ' . mysqli_error($con));
    }
}

如果你想实时检查用户名是否可用（比如@Arun pointed），也许这会有点帮助。