将Laravel改为utf8mb4，以支持现有数据库中的Emoji

Question

我正在使用Laravel5.3，并且我已经设置了我的生产服务器。所有DB迁移都已使用以下数据库配置创建：

'mysql' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST', 'localhost'),
            'port' => env('DB_PORT', '3306'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'charset' => 'utf8',
            'collation' => 'utf8_unicode_ci',
            'prefix' => '',
            'strict' => true,
            'engine' => null,
        ],

但现在，我的一些用户报告说，当他们试图保存一个包含表情符号图标的表单时，会发现一个错误。搜索之后，我发现我需要将mysql字符集设置为utf8mb4，所以我的配置应该是这样的：

'mysql' => [
            'driver' => 'mysql',
            'host' => env('DB_HOST', 'localhost'),
            'port' => env('DB_PORT', '3306'),
            'database' => env('DB_DATABASE', 'forge'),
            'username' => env('DB_USERNAME', 'forge'),
            'password' => env('DB_PASSWORD', ''),
            'charset' => 'utf8mb4',
            'collation' => 'utf8mb4_unicode_ci',
            'prefix' => '',
            'strict' => true,
            'engine' => null,
        ],

因为这是在生产服务器中，所以我不能执行migrate:refresh。所以我的问题是：

1. 如何将我使用laravel迁移创建的现有数据库更改为使用utf8mb4而不是utf8，并在相同的数据库上更新laravel？有更简单的方法吗？
2. 如果可能的话，我是否最好为所有表设置utf8mb4，还是只对两个表列使用，而我将在其中真正使用表情符号。

谢谢你的帮助。

Answer 1

1. 使用原始mysql查询编写更新表迁移脚本并运行php artisan migrate命令 使用照明\数据库\迁移；类UpdateTableCharset扩展迁移{ /** *运行迁移。**@返回void */ public函数up() {DB：：un准备(‘ALTER table\_name转换为字符集utf8mb4')；} /** *反转迁移。**@返回void */ public function (){DB：：un准备(‘ALTER table\_name转换为字符集utf8')；}
2. 我个人的喜好，更新表。我没有证据说这更好

注意:您仍然必须将数据库配置保持为utf8mb4。

Answer 2

基于@失眠症开发的答案，但只有当它们超过极限并在索引中使用时才会收缩varchar。否则，它们将被转换，但大小将保持不变。如果某列将缩小，则检查是否会截断任何数据。

这还处理所有文本类型和批处理每个表的所有转换为单个语句的速度。

Dryrun标志输出可用的sql，而不是直接应用。

/**
 * Run the migrations.
 *
 * @return void
 */
public function up()
{
    $dryRun = true;
    $this->convertDb('mysql', 'utf8mb4', 'utf8mb4_unicode_ci', $dryRun);
    $this->convertDb('archive', 'utf8mb4', 'utf8mb4_unicode_ci', $dryRun);
}

/**
 * Reverse the migrations.
 *
 * @return void
 */
public function down()
{
    $dryRun = true;
    $this->convertDb('archive', 'utf8', 'utf8_unicode_ci', $dryRun);
    $this->convertDb('mysql', 'utf8', 'utf8_unicode_ci', $dryRun);
}

private function convertDb($connection, $charset, $collate, $dryRun)
{
    $dbName = config("database.connections.{$connection}.database");

    $varchars = \DB::connection($connection)
        ->select(\DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE = 'varchar' and (CHARACTER_SET_NAME != '{$charset}' or COLLATION_NAME != '{$collate}') AND TABLE_SCHEMA = '{$dbName}'"));
    // Check if shrinking field size will truncate!
    $skip = [];  // List of table.column that will be handled manually
    $indexed = [];
    if ($charset == 'utf8mb4') {
        $error = false;
        foreach($varchars as $t) {
            if ($t->CHARACTER_MAXIMUM_LENGTH > 191) {
                $key = "{$t->TABLE_NAME}.{$t->COLUMN_NAME}";

                // Check if column is indexed
                $index = \DB::connection($connection)
                    ->select(\DB::raw("SHOW INDEX FROM `{$t->TABLE_NAME}` where column_name = '{$t->COLUMN_NAME}'"));
                $indexed[$key] = count($index) ? true : false;

                if (count($index)) {
                    $result = \DB::connection($connection)
                        ->select(\DB::raw("select count(*) as `count` from `{$t->TABLE_NAME}` where length(`{$t->COLUMN_NAME}`) > 191"));
                    if ($result[0]->count > 0) {
                        echo "-- DATA TRUNCATION: {$t->TABLE_NAME}.{$t->COLUMN_NAME}({$t->CHARACTER_MAXIMUM_LENGTH}) => {$result[0]->count}" . PHP_EOL;
                        if (!in_array($key, $skip)) {
                            $error = true;
                        }
                    }
                }
            }
        }
        if ($error) {
            throw new \Exception('Aborting due to data truncation');
        }
    }

    $query = "SET FOREIGN_KEY_CHECKS = 0";
    $this->dbExec($query, $dryRun, $connection);

    $query = "ALTER SCHEMA {$dbName} DEFAULT CHARACTER SET {$charset} DEFAULT COLLATE {$collate}";
    $this->dbExec($query, $dryRun, $connection);

    $tableChanges = [];
    foreach($varchars as $t) {
        $key = "{$t->TABLE_NAME}.{$t->COLUMN_NAME}";
        if (!in_array($key, $skip)) {
            if ($charset == 'utf8mb4' && $t->CHARACTER_MAXIMUM_LENGTH > 191 && $indexed["{$t->TABLE_NAME}.{$t->COLUMN_NAME}"]) {
                $tableChanges["{$t->TABLE_NAME}"][] = "CHANGE `{$t->COLUMN_NAME}` `{$t->COLUMN_NAME}` VARCHAR(191) CHARACTER SET {$charset} COLLATE {$collate}";
                echo "-- Shrinking: {$t->TABLE_NAME}.{$t->COLUMN_NAME}({$t->CHARACTER_MAXIMUM_LENGTH})" . PHP_EOL;
            } else if ($charset == 'utf8' && $t->CHARACTER_MAXIMUM_LENGTH == 191) {
                $tableChanges["{$t->TABLE_NAME}"][] = "CHANGE `{$t->COLUMN_NAME}` `{$t->COLUMN_NAME}` VARCHAR(255) CHARACTER SET {$charset} COLLATE {$collate}";
                echo "-- Expanding: {$t->TABLE_NAME}.{$t->COLUMN_NAME}({$t->CHARACTER_MAXIMUM_LENGTH})";
            } else {
                $tableChanges["{$t->TABLE_NAME}"][] = "CHANGE `{$t->COLUMN_NAME}` `{$t->COLUMN_NAME}` VARCHAR({$t->CHARACTER_MAXIMUM_LENGTH}) CHARACTER SET {$charset} COLLATE {$collate}";
            }
        }
    }

    $texts = \DB::connection($connection)
        ->select(\DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE like '%text%' and (CHARACTER_SET_NAME != '{$charset}' or COLLATION_NAME != '{$collate}') AND TABLE_SCHEMA = '{$dbName}'"));
    foreach($texts as $t) {
        $tableChanges["{$t->TABLE_NAME}"][] = "CHANGE `{$t->COLUMN_NAME}` `{$t->COLUMN_NAME}` {$t->DATA_TYPE} CHARACTER SET {$charset} COLLATE {$collate}";
    }

    $tables = \DB::connection($connection)
        ->select(\DB::raw("select * from INFORMATION_SCHEMA.TABLES where TABLE_COLLATION != '{$collate}' and TABLE_SCHEMA = '{$dbName}';"));
    foreach($tables as $t) {
        $tableChanges["{$t->TABLE_NAME}"][] = "CONVERT TO CHARACTER SET {$charset} COLLATE {$collate}";
        $tableChanges["{$t->TABLE_NAME}"][] = "DEFAULT CHARACTER SET={$charset} COLLATE={$collate}";
    }

    foreach ($tableChanges as $table => $changes) {
        $query = "ALTER TABLE `{$table}` ".implode(",\n", $changes);
        $this->dbExec($query, $dryRun, $connection);
    }

    $query = "SET FOREIGN_KEY_CHECKS = 1";
    $this->dbExec($query, $dryRun, $connection);

    echo "-- {$dbName} CONVERTED TO {$charset}-{$collate}" . PHP_EOL;
}

private function dbExec($query, $dryRun, $connection)
{
    if ($dryRun) {
        echo $query . ';' . PHP_EOL;
    } else {
        \DB::connection($connection)->getPdo()->exec($query);
    }
}

Answer 3

对于任何愿意在整个数据库中实现这一目标的人，我发现自己需要这样一个脚本：

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Config;

class ChangeDbCharset extends Migration
{

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        $charset = "utf8mb4";
        $collate = $charset."_unicode_ci";
        $dbName = Config::get('database.connections.'.Config::get('database.default').'.database');
        $query = "ALTER SCHEMA $dbName DEFAULT CHARACTER SET $charset DEFAULT COLLATE $collate;\n"; 
        DB::connection()->getPdo()->exec($query);

        $dbName = Config::get('database.connections.'.Config::get('database.default').'.database');
        $result = DB::select(DB::raw('show tables'));
        $test = DB::select(DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE = 'varchar' AND TABLE_SCHEMA = '$dbName';"));
        //var_dump($test);
        foreach($test as $t)
        {
            $query = "ALTER TABLE $t->TABLE_NAME CHANGE $t->COLUMN_NAME $t->COLUMN_NAME VARCHAR(191) CHARACTER SET $charset COLLATE $collate; \n";
            echo $query;
            DB::connection()->getPdo()->exec($query);
        }
        $test = DB::select(DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE = 'text' AND TABLE_SCHEMA = '$dbName';"));
        foreach($test as $t)
        {
            $query = "ALTER TABLE $t->TABLE_NAME CHANGE $t->COLUMN_NAME $t->COLUMN_NAME TEXT CHARACTER SET $charset COLLATE $collate; \n";
            echo $query;
            DB::connection()->getPdo()->exec($query);
        }


        $result = DB::select(DB::raw('show tables'));
        foreach($result as $r)
        {
            foreach($r as $k => $t)
            {
                $query = "ALTER TABLE `$t` CONVERT TO CHARACTER SET $charset COLLATE $collate; \n";
                echo $query;
                DB::connection()->getPdo()->exec($query);
            }
        }
        echo "DB CHARSET set to $charset , $collate";
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        $charset = "utf8";
        $collate = $charset."_unicode_ci";
        $dbName = Config::get('database.connections.'.Config::get('database.default').'.database');
        $query = "ALTER SCHEMA $dbName DEFAULT CHARACTER SET $charset DEFAULT COLLATE $collate;\n"; 
        DB::connection()->getPdo()->exec($query);

        $dbName = Config::get('database.connections.'.Config::get('database.default').'.database');
        $result = DB::select(DB::raw('show tables'));
        $test = DB::select(DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE = 'varchar' AND TABLE_SCHEMA = '$dbName';"));
        //var_dump($test);
        foreach($test as $t)
        {
            $query = "ALTER TABLE $t->TABLE_NAME CHANGE $t->COLUMN_NAME $t->COLUMN_NAME VARCHAR(255) CHARACTER SET $charset COLLATE $collate; \n";
            echo $query;
            DB::connection()->getPdo()->exec($query);
        }
        $test = DB::select(DB::raw("select * from INFORMATION_SCHEMA.COLUMNS where DATA_TYPE = 'text' AND TABLE_SCHEMA = '$dbName';"));
        foreach($test as $t)
        {
            $query = "ALTER TABLE $t->TABLE_NAME CHANGE $t->COLUMN_NAME $t->COLUMN_NAME TEXT CHARACTER SET $charset COLLATE $collate; \n";
            echo $query;
            DB::connection()->getPdo()->exec($query);
        }


        $result = DB::select(DB::raw('show tables'));
        foreach($result as $r)
        {
            foreach($r as $k => $t)
            {
                $query = "ALTER TABLE `$t` CONVERT TO CHARACTER SET $charset COLLATE $collate; \n";
                echo $query;
                DB::connection()->getPdo()->exec($query);
            }
        }
        echo "DB CHARSET set to $charset , $collate";
    }

}