From a802e27de73cafefe215e0318314753112b532d0 Mon Sep 17 00:00:00 2001
From: Summer <summer@learnku.com>
Date: Fri, 20 Sep 2019 04:25:07 +0000
Subject: [PATCH] =?UTF-8?q?=E8=81=94=E5=8A=A8=E5=88=A0=E9=99=A4?=
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---
 .../2019_09_20_122431_add_references.php      | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 database/migrations/2019_09_20_122431_add_references.php

diff --git a/database/migrations/2019_09_20_122431_add_references.php b/database/migrations/2019_09_20_122431_add_references.php
new file mode 100644
index 000000000..3261049d5
--- /dev/null
+++ b/database/migrations/2019_09_20_122431_add_references.php
@@ -0,0 +1,40 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class AddReferences extends Migration
+{
+    public function up()
+    {
+        Schema::table('topics', function (Blueprint $table) {
+
+            // 当 user_id 对应的 users 表数据被删除时，删除词条
+            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
+        });
+
+        Schema::table('replies', function (Blueprint $table) {
+
+            // 当 user_id 对应的 users 表数据被删除时，删除此条数据
+            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
+
+            // 当 topic_id 对应的 topics 表数据被删除时，删除此条数据
+            $table->foreign('topic_id')->references('id')->on('topics')->onDelete('cascade');
+        });
+    }
+
+    public function down()
+    {
+        Schema::table('topics', function (Blueprint $table) {
+            // 移除外键约束
+            $table->dropForeign(['user_id']);
+        });
+
+        Schema::table('replies', function (Blueprint $table) {
+            $table->dropForeign(['user_id']);
+            $table->dropForeign(['topic_id']);
+        });
+
+    }
+}