SQLSTATE [23000]:违反完整性约束:1217 [英] SQLSTATE[23000]: Integrity constraint violation: 1217

问题描述

在我的项目中进行了多次迁移之后，我想回滚以更新一些内容，但是当我尝试删除 projects 表时突然出现了此错误.我仔细检查了外键约束，但找不到错误.

After creatin multiple migrations in my project, I wanted to rollback to update a few things but suddenly I got this error when I tried to drop projects table. I double checked the foreign key constrains but I can't find the error.

[Illuminate\Database\QueryException]                                         
  SQLSTATE[23000]: Integrity constraint violation: 1217 Cannot delete or upda  
  te a parent row: a foreign key constraint fails (SQL: drop table `projects`  
  )                                                                                                                                                           
  [PDOException]                                                               
  SQLSTATE[23000]: Integrity constraint violation: 1217 Cannot delete or upda  
  te a parent row: a foreign key constraint fails  

这是我的迁移:1.创建表用户:

Here are my migrations: 1.create table users:

public function up()
    {
        Schema::create('users', function(Blueprint $table)
        {
            $table->increments('id');
            $table->string('first_name');
            $table->string('last_name');
            $table->string('email', 50)->unique();
            $table->string('password', 60);
            $table->string('password_temp', 60);
            $table->string('code', 60);
            $table->boolean('active');
            $table->string('remember_token', 100);
            $table->timestamps();
        });
    }
    public function down()
    {
        Schema::drop('users');
    }

2.创建客户表:

public function up()
    {
        Schema::create('clients', function(Blueprint $table)
        {
            $table->increments('id');
            $table->integer('user_id')->unsigned()->index()->nullable();
            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
            $table->timestamps();
        });
    }
    public function down()
    {
        Schema::drop('clients');
    }

3.创建项目表:

public function up()
    {
        Schema::create('projects', function(Blueprint $table)
        {
            $table->increments('id');
            $table->string('name');
            $table->integer('status');
            $table->integer('client_id')->unsigned()->index()->nullable();
            $table->foreign('client_id')->references('id')->on('users')->onDelete('cascade');    
            $table->timestamps();
        });
    }
    public function down()
    {
        Schema::drop('projects');
    }

在上一次迁移中，我可能正在做的错误是什么?！迁移时我没有遇到任何麻烦，但仅当我回滚以添加任何更改时才会出现.

In the last migration, what could possibly be the mistake I am doing?! I face no trouble when migrating but it appears only when I rollback to add any changes.

知道为什么会这样吗?

推荐答案

如果上面仅提到3个表，那么您的迁移就没有问题，因为我自己用

If there are only 3 tables above mentioned, there is no issue in your migration as I have tried it myself with

php artisan migrate

创建表和

php artisan migrate:rollback

要回滚.

我知道的一件事是Laravel将基于迁移文件时间戳假定迁移的顺序.

One thing that I know is Laravel is going to assume the sequence of the migration based on the migration file timestamp.

因此，我非常确定还有另一个表，该表具有对 projects 表的外键引用，该表尚未因错误消息而被删除(SQL:drop table projects )

Therefore, I am quite sure there is another table that has a foreign key reference to the projects tables that has not been dropped as the error messsage is (SQL: drop table projects)

尝试使用 php artisan tinker ，然后使用 Schema :: drop('some_table_name'); ，其中 some_table_name 是具有参考的表到 projects 表，然后再次删除 projects 表.

Try to use php artisan tinker and then Schema::drop('some_table_name'); where some_table_name is the table that has reference to projects table, then drop the projects table again.

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