Problem Description:

php artisan migrate Error:

Illuminate\Database\QueryException 

  SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes (SQL: alter table `users` add unique `users_em
ail_unique`(`email`))

Cause Analysis:
The maximum character length of utf8 encoding supported by MySql is 3 bytes, if a wide character of 4 bytes is encountered, an insertion exception will occur. The maximum Unicode character that can be encoded by three bytes UTF-8 is 0xffff, which is the basic multiliterate plane (BMP) in Unicode. Therefore, Unicode characters that are not in the Basic Multicultural Plane, including Emoji emojis (Emoji is a special Unicode encoding), cannot be stored using MySql’s utf8 character set.

This should also be one of the reasons why Laravel 5.4 switched to the 4-byte length utf8mb4 character encoding. However, it should be noted that the utf8mb4 character encoding is only supported from MySql version 5.5.3 onwards (check the version: selection version();). If the MySql version is too low, a version update is required.

Solution:
1. Upgrade MySql version to 5.5.3 or higher. Add in /app/providers/AppServiceProvider.php:

use Illuminate\Support\Facades\Schema;

public function boot()
    {
        Schema::defaultStringLength(191);
    }

2. Delete the table in the database and re execute php artisan migrate