无法在 Laravel 中添加外键

Question

当我尝试迁移时出现错误 "Foreign key constraint is incorrectly formed"，但我不明白为什么

第一table

    Schema::create('uciteles', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('name');
        $table->integer('admin');
        $table->string('predmet');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->rememberToken();
        $table->timestamps();

        $table->unsignedBigInteger('user_id');

        $table->foreign('user_id')->references('id')->on('users');
    });

第 2 table

Schema::create('users', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->rememberToken();
        $table->timestamps();

    });

Answer 1

列的类型必须与外键引用中的相同，您需要自己创建列。

以下是对您问题的解释：Creating Foreign Key in Laravel Migrations

Answer 2

我认为您首先要创建 uciteles table，然后是用户 table。所以在这里更改 format.first 创建用户 table & 然后 uciteles table.

像这样在迁移中更改创建时间 table 2019_09_27_000000_create_users_table.php 更改日期和月份然后用户 table 首先创建 uciteles table 或禁用外键检查并启用它

DB::statement('SET FOREIGN_KEY_CHECKS=0;');
Schema::create('uciteles', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('name');
        $table->integer('admin');
        $table->string('predmet');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->rememberToken();
        $table->timestamps();

        $table->unsignedBigInteger('user_id');

        $table->foreign('user_id')->references('id')->on('users');
    });
DB::statement('SET FOREIGN_KEY_CHECKS=1;');

无法在 Laravel 中添加外键

Cant add foreign key in Laravel

migration

foreign-keys

primary-key

laravel