Question

我将字符串属性设置为主键，现在我想在2个表之间建立关系。我希望在另一个表中声明字符串外键，以确保这两个表已连接。但是当我要迁移表时出现错误

国家/地区

Schema::create('countries', function (Blueprint $table) {
    $table->string('country_name')->unique();
    $table->primary('country_name');
    $table->string('country_img');
    $table->timestamps();
});

目的地

Schema::create('destinations', function (Blueprint $table) {
    $table->increments('dest_id');
    $table->string('dest_name');
    $table->integer('dest_budget');
    $table->double('dest_hrs');
    $table->string('dest_country')->unsigned();
    $table->foreign('dest_country')->references('country_name')->on('countries');
    $table->string('dest_state');
    $table->string('dest_address');
    $table->string('lat');
    $table->string('lng');
    $table->string('dest_info');
    $table->string('dest_ctgr');
    $table->string('dest_img');
    $table->timestamps();
});

国家/地区模型

protected $primaryKey = 'country_name';
public $incrementing = false;
protected $fillable = ['country_name', 'country_img'];

public function destinasi(){

    return $this->hasMany(Destination::class);
}

目的地模型

protected $primaryKey = 'dest_id';
protected $fillable = ['dest_name','dest_address','lat','lng','dest_ctgr','dest_budget','dest_hrs','dest_country','dest_state','dest_info','dest_img'];

public function country() {
    return $this->belongsTo(Country::class);
}

我收到此错误：

SQLSTATE [42000]：语法错误或访问冲突：1064您有一个 SQL语法错误

我认为我编写外键的方法是错误的，并导致出现此错误。

Answer 1

在“目标”模式中

替换

$table->foreign('dest_country')->references('country_name')->on('countries');

使用

$table->string('dest_country');

在您的模型中

public function country(){

    return $this->belongsTo('App\Country', 'dest_country');
}

Answer 2

仅在创建列之后才指定外键，因此您的迁移应为

Schema::create('destinations', function (Blueprint $table) {
        $table->increments('dest_id');
        $table->string('dest_name');
        $table->integer('dest_budget');
        $table->double('dest_hrs');
        $table->string('dest_country');
        $table->string('dest_country');
        $table->string('dest_state');
        $table->string('dest_address');
        $table->string('lat');
        $table->string('lng');
        $table->string('dest_info');
        $table->string('dest_ctgr');
        $table->string('dest_img');
        $table->timestamps();

        $table->foreign('dest_country')->references('country_name')->on('countries')->onUpdate('cascade')->onDelete('cascade');;
    });

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设置字符串外键在Laravel中不起作用

2 个答案: