SQLSTATE [HY000]:常规错误:1215无法添加外键约束

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我正在尝试创建一个表格来保存照片并将其链接到广告(属性ID). 我收到此错误

I'm trying to create a table to hold photos and link it to the ad (property id). I'm getting this error

SQLSTATE [HY000]:常规错误:1215无法添加外键约束

SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint

这些是我的迁移文件

2018_02_14_191609_create_property_adverts_table

2018_02_14_191609_create_property_adverts_table

<?php use Illuminate\Support\Facades\Schema; use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration; class CreatePropertyAdvertsTable extends Migration { /** * Run the migrations. * * @return void */ public function up() { Schema::create('property_adverts', function (Blueprint $table) { $table->increments('id'); $table->string('address'); $table->string('county'); $table->string('town'); $table->string('type'); $table->string('rent'); $table->string('date'); $table->string('bedrooms'); $table->string('bathrooms'); $table->string('furnished'); $table->longText('description'); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::dropIfExists('property_adverts'); } }

2018_02_18_165845_create_property_advert_photos_table

2018_02_18_165845_create_property_advert_photos_table

<?php use Illuminate\Support\Facades\Schema; use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration; class CreatePropertyAdvertPhotosTable extends Migration { /** * Run the migrations. * * @return void */ public function up() { Schema::create('property_advert_photos', function (Blueprint $table) { $table->increments('id'); $table->integer('propertyadvert_id')->nullable(); $table->foreign('propertyadvert_id')->references('id')->on('property_adverts'); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::dropIfExists('property_advert_photos'); } }

所以

推荐答案

将其设为unsigned，因为您正在使用increments().并将FK约束部分移至单独的闭包中:

Make it unsigned because you're using increments(). And move FK constraint part to a separate closure:

public function up() { Schema::create('property_advert_photos', function (Blueprint $table) { $table->increments('id'); $table->unsignedInteger('propertyadvert_id')->nullable(); $table->timestamps(); }); Schema::table('property_advert_photos', function (Blueprint $table) { $table->foreign('propertyadvert_id')->references('id')->on('property_adverts'); }); }