laravel 8执行数据库迁移文件出错的原因和解决方案

背景：

laravel 8 ，要迁移的mysql表数据结构如下：

cars表：

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+-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | id | int unsigned | NO | PRI | NULL | auto_increment | | name | varchar(255) | NO | | NULL | | | founded | int | NO | | NULL | | | description | longtext | NO | | NULL | | | created_at | timestamp | YES | | NULL | | | updated_at | timestamp | YES | | NULL | | +-------------+--------------+------+-----+---------+----------------+

car_models表：

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+------------+--------------+------+-----+---------+----------------+ | Field      | Type         | Null | Key | Default | Extra          | +------------+--------------+------+-----+---------+----------------+ | id         | int unsigned | NO   | PRI | NULL    | auto_increment | | car_id     | int unsigned | NO   | MUL | NULL    |                | | model_name | varchar(255) | NO   |     | NULL    |                | | created_at | timestamp    | YES  |     | NULL    |                | | updated_at | timestamp    | YES  |     | NULL    |                | +------------+--------------+------+-----+---------+----------------+

 

执行 php artisan migrate ，报错：SQLSTATE[HY000]: General error: 3780 Referencing column 'car_id' and referenced column 'id' in foreign key constraint 'car_models_car_id_foreign' are incompatible.

 

分析：根据提示，可以看出是说car_id和id不兼容，导致这个问题的原因是laravel 8 生成的migration里，默认使用的是$table->id()，需要改成$table->increment('id')