php - 一般错误 1215 : Cannot Add Foreign Key Constraint for Laravel 5

Question

下面是我尝试按所述顺序运行的两个迁移。变量类型是相同的，我在制作表格后添加了 FK，但它仍然向我抛出 1215 Cannot addforeign keyconstraint 错误。

General Error 1215: Cannot Add Foreign Key Constraint for Laravel 5

2019_12_10_130856_all_skillset.php

public function up(){
    Schema::create('all_skillsets', function(Blueprint $table){
        $table->increments('id');
        $table->char('skillset');
    });
}

2019_12_10_300000_skillset.php

public function up(){
    Schema::create('skillsets', function(Blueprint $table){
        $table->increments('id');
        $table->unsignedInteger('spid');
        $table->char('skill');
    });

    Schema::table('skillsets', function(Blueprint $table){
        $table->foreign('skill')->references('skillset')->on('all_skillsets');
        $table->foreign('spid')->references('id')->on('players');
    });
}

Answer 1

错误一定是针对这一行:

$table->foreign('skill')->references('skillset')->on('all_skillsets');

您应该引用主键all_skillsets表。不要忘记外键类型必须等于所有者的 key 类型。

例如如果您使用 increment 定义所有者 key ，则必须使用 unsignedInteger 定义外键。