SQLSTATE[HY000]: General error: 1005 Can't create table `Projectname`.`users` (errno: 150 "Foreign key constraint is incorrectly formed")

Question

Schema::create('projects', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

Schema::create('users', function (Blueprint $table) {
    $table->id();
    $table->foreignId('project_id')->constrained();
    $table->string('name');
    $table->string('email')->unique();
    $table->timestamp('email_verified_at')->nullable();
    $table->string('password');
    $table->rememberToken();
    $table->timestamps();
});

Schema::create('tasks', function (Blueprint $table) {
    $table->id();
    $table->foreignId('user_id')->constrained();
    $table->string('name');
    $table->timestamps();
});

当我运行 php artisan migrate 仅创建用户 table 时，迁移过程停止...

SQLSTATE[HY000]: General error: 1005 Can't create table Projectname.users (errno: 150 "Foreign key constraint is incorrectly formed") (SQL: alter table users add constraint users_project_id_foreign foreign key (project_id) references projects (id))

Answer 1

您使用的 constrained() 往往会找到 table project 或 user 而不是 projects 或 users。在这种情况下，您需要在 constrained().

中指定 table 名称

Schema::create('projects', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

Schema::create('users', function (Blueprint $table) {
    $table->id();
    $table->foreignId('project_id')->constrained('projects');
    $table->string('name');
    $table->string('email')->unique();
    $table->timestamp('email_verified_at')->nullable();
    $table->string('password');
    $table->rememberToken();
    $table->timestamps();
});

Schema::create('tasks', function (Blueprint $table) {
    $table->id();
    $table->foreignId('user_id')->constrained('users');
    $table->string('name');
    $table->timestamps();
});

您可以从 here

中了解更多

Answer 2

查找您的 migration 目录，您将看到所有迁移文件，例如 2014_10_12_000000_create_users_table

You are getting this error because your projects_create_table should be migrate before create_users_table file.

默认情况下，laravel 使每个迁移文件名都采用date_time 格式，如2014_10_12_000000_table_names.php 这样，所有文件都可以按顺序迁移。
因此，将您的 create_users_table 文件名更改为 date_time，以便可以在 projects_create_table 之后迁移，喜欢 :

2020_01_01_000000_create_projects_table.php
2020_01_01_000001_create_users_table.php

现在，如果你运行php artisan migrate，首先会创建projectstable，然后userstable。

SQLSTATE[HY000]: General error: 1005 Can't create table `Projectname`.`users` (errno: 150 "Foreign key constraint is incorrectly formed")

SQLSTATE[HY000]: General error: 1005 Can't create table `Projectname`.`users` (errno: 150 "Foreign key constraint is incorrectly formed")

php

mysql

laravel

laravel-migrations

laravel-7