Laravel 5.2迁移外键

I am new to web development in Laravel 5.2 and I have this problem. I have a Users and Jobseekers tables and I am trying to create a foreign key in the Jobseekers table that references the Users table using migration but when I run php artisan migrate I get the error

我是Laravel 5.2的web开发新手，我有这个问题。我有一个用户和求职者表，我试图在求职者表中创建一个外键，它使用迁移引用用户表，但是当我运行php artisan迁移时，我得到了错误。

[Illuminate\Database\QueryException] SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key cons traint fails (jobsitelara.#sql-1a04_7d, CONSTRAINT jobseekers_user_id_foreign FOREIGN KEY (user_id ) REFERENCES users (id)) (SQL: alter table jobseekers add constraint jobseekers_user_id_foreign fore ign key (user_id) references users (id))

[照亮数据库\QueryException] SQLSTATE[23000]:完整性约束违例:1452不能添加或更新一个子行:外键出错(jobsitelara)。# SQL -1a04_7d，约束jobseekers_user_id_foreign KEY (user_id)引用用户(id)

[PDOException] SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key cons traint fails (jobsitelara.#sql-1a04_7d, CONSTRAINT jobseekers_user_id_foreign FOREIGN KEY (user_id ) REFERENCES users (id))

[PDOException] SQLSTATE[23000]:完整性约束违例:1452不能添加或更新子行:外键禁用失败(jobsitelara)。#sql-1a04_7d，约束jobseekers_user_id_foreign KEY (user_id)引用用户(id)

Here is the migration for create_users_table

这里是create_users_table的迁移。

public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->string('password', 60);
            $table->rememberToken();
            $table->timestamps();
        });

and the migration for create_jobseekers_table

以及create_jobseekers_table的迁移

public function up()
    {
        Schema::create('jobseekers', function (Blueprint $table) {
            $table->increments('id');
            $table->string('firstname');
            $table->string('lastname');
            $table->enum('gender',array('male','female'));
            $table->date('dateofbirth');
            $table->string('occupation', 150);
            $table->string('educationlevel', 200);
            $table->string('cv', 150);
            $table->string('skills', 200);
            $table->string('address', 200);
            $table->string('phonenumber', 30);
            $table->integer('user_id');
            $table->timestamps();
        });
    }

and the migration to create the foreign key is in a separate file that runs after the create tables migrations have been run here is the add_foreignkey_to_jobseekers_table migration

创建外键的迁移是在创建表迁移之后运行的一个单独文件中，这里是add_foreignkey_to_jobseekers_table迁移

public function up()
{
    Schema::table('jobseekers', function (Blueprint $table) {
        $table->foreign('user_id')->references('id')->on('users');
    });
}

I made sure that the user_id field in the Jobseekers table is also unsigned. I noticed that the tables are referenced as jobsitelara'.'#sql-1a04_8f' in the error messages, I don't understand what's going on. What else is wrong with my code?

我确保jobfinder表中的user_id字段也没有签名。我注意到这些表被引用为jobsitelara'。在错误信息中，我不知道发生了什么。我的代码还有什么问题吗?

2 个解决方案

#1

In Laravel Database Migrations, you need to have clear the order of your migrations and the parent – child relationship between your tables. Therefore, when you create tables, you need to create parent tables first and then child tables.

在Laravel数据库迁移中，您需要清楚迁移的顺序以及表之间的父-子关系。因此，在创建表时，需要先创建父表，然后创建子表。

In the Other hand, when you delete tables, you need to delete child tables first and then parents.

另一方面，在删除表时，需要先删除子表，然后删除父表。

@Martin Bean has an explanation on this topic What is a Parent table and a Child table in Database.

@Martin Bean对这个主题有一个解释，什么是数据库中的父表和子表。

When you run in your terminal php artisan migrate: --options--, your functions up and down will be called respectively depending on the option you pass to migrate. If you order your migrations having parent-child relationships clear, you won’t have this problem.

当您在终端php中运行artisan migration: -options时，根据您传递给migration的选项，将分别调用您的函数up和down。如果你命令你的迁移有亲子关系，你就不会有这个问题。

There are also other situations that you should consider when designing your database, like recursive relationships between tables which @Branko Dimitrijevic explains in this topic Database design for a recursive relationship.

在设计数据库时还应该考虑其他情况，比如表之间的递归关系，在本主题数据库设计中，@Branko Dimitrijevic解释了这种关系。

Hope it helps!

希望它可以帮助!

#2

public function up()
    {
        Schema::create('jobseekers', function (Blueprint $table) {
            $table->increments('id');
            $table->string('firstname');
            $table->string('lastname');
            $table->enum('gender',array('male','female'));
            $table->date('dateofbirth');
            $table->string('occupation', 150);
            $table->string('educationlevel', 200);
            $table->string('cv', 150);
            $table->string('skills', 200);
            $table->string('address', 200);
            $table->string('phonenumber', 30);
            $table->timestamps();
        });
    }


public function up()
{
    Schema::table('jobseekers', function (Blueprint $table) {
        $table->integer('user_id')->unsigned();
        $table->foreign('user_id')->references('id')->on('users');
    });
}

Remove user_id string from the create_jobseekers_table and put following foreign key table code on add_foreignkey_to_jobseekers_table

从create_jobseekers_table中删除user_id字符串，并在add_foreignkey_to_jobseekers_table上放置以下外键表代码

#1