Laravel迁移错误号：150“外键约束格式不正确”

Question

我有一个帖子表和一个到达表，它引用了flight no（文本字符串格式）作为外键。然而，当我运行Laravel迁移时，我得到了可怕的错误：

SQLSTATE[HY000]：常规错误： 1005不能创建表atc.#sql-2350_84（errno： 150"外键约束格式不正确"）（SQL：改变表到达添加约束arrival_flightno_foreign外键（flight no）引用帖子（flight no）

[PDOExc0019]SQLSTATE[HY000]：常规错误： 1005不能创建表atc.#sql-2350_84（errno： 150"外键约束格式不正确"）

职位

Schema::create('posts', function (Blueprint $table) {
    $table->increments('id');
    $table->string('flightno');
    $table->string('flighttype');
    $table->string('toa');
    $table->string('doa');
    $table->string('runway');
    $table->string('route');
    $table->string('parking');
    $table->timestamps();
}); 

到达

Schema::create('arrival', function (Blueprint $table) {
    $table->increments('id');
    $table->string('flightno');
    $table->string('cleaning');
    $table->string('rampservice');
    $table->string('waste');
    $table->string('deicing');
    $table->foreign('flightno')->references('flightno')->on('posts')->onDelete('cascade');
    $table->timestamps();
});

Answer 1

在外键列中使用unsignedBigintger以避免不匹配的外键数据类型问题。

例如，在arrival表中，使用flightno的类型作为unsignedBigInteger。

帖子：

Schema::create('posts', function (Blueprint $table) {
    $table->increments('id');
    $table->string('flightno');
    $table->string('flighttype');
    $table->string('toa');
    $table->string('doa');
    $table->string('runway');
    $table->string('route');
    $table->string('parking');
    $table->timestamps();
});

抵达：

Schema::create('arrival', function (Blueprint $table) {
    $table->increments('id');
    //---Change flightno type to unsignedBigInteger and if u faced any problem just use nullable at the end of flightno.
    $table->unsignedBigInteger('flightno');
    $table->string('cleaning');
    $table->string('rampservice');
    $table->string('waste');
    $table->string('deicing');
    $table->foreign('flightno')->references('flightno')->on('posts')->onDelete('cascade');
    $table->timestamps();
});

它将解决许多人面临的问题。

Answer 2

在我看来，您忘记了放置索引和设置flightno列的长度。这应该起作用：

职位

Schema::create('posts', function (Blueprint $table) {
    // ...
    $table->string('flightno', 30)->index();
    // ...
}); 

到达

Schema::create('arrival', function (Blueprint $table) {
    // ...
    $table->string('flightno', 30)->index();
    // ...
});