Question

我有两张桌子（员工和地区），

employees and regions

我正在尝试使用迁移创建它，不幸的是它不会让我，我得到：

[Illuminate\Database\QueryException]
SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table regions` add constraint regions_create_by_foreign foreign key (`create_by`) references `employees` (`id`))

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

以下是我的迁移代码：

FILE: 2014_10_11_052414_create_regions_table.php  //this is the migration file for regions

    Schema::create('regions', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('name',50)->unique();
        $table->integer('head_office_flag');
        $table->integer('create_by')->unsigned();
        $table->foreign('create_by')->references('id')->on('employees'); //this is the problem
        $table->datetime('create_datetime')->default(DB::raw('CURRENT_TIMESTAMP'));
    });

FILE: 2014_10_12_110447_create_employees_table.php //this is the migration file for employees

    Schema::create('employees', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('first_name',50);
        $table->string('surname',50);
        $table->string('email',100);
        $table->integer('region_id');   
        $table->string('photos',255)->nullable();
        $table->string('mobile_no',50);
        $table->string('office_no',50)->nullable();
        $table->string('landline_no',50)->nullable();
        $table->integer('create_by')->unsigned();                    
        $table->foreign('create_by')->references('id')->on('employees'); //this is the problem to reference to itself
        $table->datetime('create_datetime')->default(DB::raw('CURRENT_TIMESTAMP'));
        $table->integer('status');
    });

我的问题是：

我是否需要改变迁移顺序？考虑两者都有彼此的外键。 *注意，我尝试通过重命名文件并在文件名中使用更早的时间戳来更改序列
我应该添加哪些附加代码？
我是否需要在播种机中添加其他代码？

提前致谢！欢呼声。

更新

@Marcin：我已将其更新为：

FILE: 2014_10_11_052414_create_regions_table.php

    Schema::create('regions', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('name',50)->unique();
        $table->integer('head_office_flag');
        $table->integer('create_by')->unsigned();
        $table->datetime('create_datetime')->default(DB::raw('CURRENT_TIMESTAMP'));
    });

FILE: 2014_10_11_110447_create_employees_table.php

    Schema::create('employees', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('first_name',50);
        $table->string('surname',50);
        $table->string('email',100);
        $table->integer('region_id')->unsigned();
        $table->string('photos',255)->nullable();
        $table->string('mobile_no',50);
        $table->string('office_no',50)->nullable();
        $table->string('landline_no',50)->nullable();
        $table->integer('create_by')->unsigned();
        $table->datetime('create_datetime')->default(DB::raw('CURRENT_TIMESTAMP'));
        $table->integer('status');
    });

FILE: 2014_10_12_065402_alter_regions_table_FK.php

    Schema::table('regions', function($table)
    {
        $table->foreign('create_by')->references('id')->on('employees');
    });

FILE: 2014_10_12_070219_alter_employees_table_FK.php

    Schema::table('employees', function($table)
    {
        $table->foreign('region_id')->references('id')->on('regions');
        $table->foreign('create_by')->references('id')->on('employees');
    });

我仍然收到错误：

！[错误] [2]

enter image description here

Answer 1

如果你有2个表互相攻击（或表中的外键反映到同一个表），你应该这样做：

为第一个表创建迁移 - 此处不使用任何外键
为第二个表创建迁移 - 此处不使用任何外键
为第一个表创建迁移 - 这里只添加外键
为第二个表创建迁移 - 这里只添加外键

你当然可以合并例如第3步和第4步，但为了便于阅读，最好将它们分开

Laravel Migration两个表外键依赖项

1 个答案: