Question

有人可以帮我吗？我是Laravel的新手，当我尝试做时：

gcc -shared -fPIC -I/home/Data/libsodium/include \
  -L/home/Data/libsodium/lib -Wl,-rpath=/home/Data/libsodium/lib \
 -o vrf.so vrf.c -lsodium

我得到了错误：

Illuminate \ Database \ QueryException：SQLSTATE [HY000]：常规错误：1215无法添加外键约束（SQL：alter table posts添加约束posts_author_id_foreign外键（author_id）在删除限制上引用了用户（id））

这是帖子表的内容：

php artisan migrate

我注意到当我评论这一行时：

<?php

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

class CreatePostsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('author_id')->unsigned();
            $table->foreign('author_id')->references('id')->on('users')->onDelete('restrict');
            $table->string('title');
            $table->string('slug')->unique();
            $table->text('excerpt');
            $table->text('body');
            $table->string('image')->nullable();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('posts');
    }
}

错误消失了，所以我想问题出在那一行。那么，有人可以告诉我什么是正确的语法或如何解决它吗？

Answer 1

两个表上的列数据类型必须相同，外键才能起作用。默认情况下，用户ID列为：

$table->bigIncrements('id');

因此，您需要使用bigInteger进行posts迁移：

$table->bigInteger('author_id')->unsigned();

Answer 2

我做了更改。这部分：

    $table->bigIncrements('id');
    $table->bigInteger('author_id')->unsigned();
    $table->foreign('author_id')->references('id')->on('users')->onDelete('restrict');
    $table->string('title');
    $table->string('slug')->unique();
    $table->text('excerpt');
    $table->text('body');
    $table->string('image')->nullable();
    $table->timestamps();

但是我再次遇到相同的错误，这是完整的错误：

Illuminate\Database\QueryException  : SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table `posts` add constraint `posts_author_id_foreign` foreign key (`author_id`) references `users` (`id`) on delete restrict)

  at /var/www/html/becauseican/vendor/laravel/framework/src/Illuminate/Database/Connection.php:664
    660|         // If an exception occurs when attempting to run a query, we'll format the error
    661|         // message to include the bindings with SQL, which will make this exception a
    662|         // lot more helpful to the developer instead of just the database's errors.
    663|         catch (Exception $e) {
  > 664|             throw new QueryException(
    665|                 $query, $this->prepareBindings($bindings), $e
    666|             );
    667|         }
    668| 

  Exception trace:

  1   PDOException::("SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint")
      /var/www/html/becauseican/vendor/laravel/framework/src/Illuminate/Database/Connection.php:458

  2   PDOStatement::execute()
      /var/www/html/becauseican/vendor/laravel/framework/src/Illuminate/Database/Connection.php:458

p.s。我还添加了这一行：

$table->engine = 'InnoDB';

但没有任何改变

Answer 3

尝试将外来ko更改为unsignedInteger

<?php

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

class CreatePostsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->increments('id');
            $table->unsignedInteger('author_id');
            $table->foreign('author_id')->references('id')->on('users')->onDelete('restrict');
            $table->string('title');
            $table->string('slug')->unique();
            $table->text('excerpt');
            $table->text('body');
            $table->string('image')->nullable();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('posts');
    }
}

SQLSTATE [HY000]：常规错误：1215无法在Laravel中添加外键约束

3 个答案: