Laravel 5迁移标识符名称太长

Question

我正在尝试运行以下迁移:

public function up()
{
    Schema::create('lifestyle_questions', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('question');
        $table->timestamps();
    });

    Schema::create('lifestyle_question_answers', function(Blueprint $table)
    {
        $table->increments('id');
        $table->integer('lifestyle_question_id')->unsigned();
        $table->foreign('lifestyle_question_id')->references('id')->on('lifestyle_questions');
        $table->string('answer');
        $table->timestamps();
    });

    Schema::create('user_lifestyle_question_answers', function(Blueprint $table)
    {
        $table->integer('user_id')->unsigned();
        $table->foreign('user_id')->references('id')->on('users');
        $table->integer('lifestyle_question_answer_id')->unsigned();
        $table->foreign('lifestyle_question_answer_id')->references('id')->on('lifestyle_question_answers');
    });
}

但是我收到以下错误:

[Illuminate\Database\QueryException]
SQLSTATE[42000]: Syntax error or access violation: 1059 Identifier name 'user_lifestyle_question_answers_lifestyle_question_answer_id_foreign' is too long (SQL: alter table `user_lifestyle_question_answers` add constraint user_lifestyle_question_answers_lifestyle_question_answer_id_foreign foreign key (`lifestyle_question_answer_id`) references `lifestyle_question_answers` (`id`))

[PDOException]
SQLSTATE[42000]: Syntax error or access violation: 1059 Identifier name 'user_lifestyle_question_answers_lifestyle_question_answer_id_foreign' is too long

Answer 1

您可以将自定义索引名称作为第二个参数传递给foreign()方法.或者只使用较短的表/列名称.

所以你想做的事情如下:

public function up()
{
    Schema::create('lifestyle_questions', function(Blueprint $table)
    {
        $table->increments('id');
        $table->string('question');
        $table->timestamps();
    });

    Schema::create('lifestyle_question_answers', function(Blueprint $table)
    {
        $table->increments('id');
        $table->integer('lifestyle_question_id')->unsigned();
        $table->foreign('lifestyle_question_id', 'lq_id_foreign')->references('id')->on('lifestyle_questions');
        $table->string('answer');
        $table->timestamps();
    });

    Schema::create('user_lifestyle_question_answers', function(Blueprint $table)
    {
        $table->integer('user_id')->unsigned();
        $table->foreign('user_id')->references('id')->on('users');
        $table->integer('lifestyle_question_answer_id')->unsigned();
        $table->foreign('lifestyle_question_answer_id', 'lqa_id_foreign')->references('id')->on('lifestyle_question_answers');
    });
}