Laravel 迁移：使用外键更改列

Question

我试图在 drop fk 之后更改列默认值，但仍然出现错误：

SQLSTATE[HY000]: General error: 1832 Cannot change column 'training_status_id': used in a foreign key constraint 'fk_user_training_training_status1_idx' (SQL: ALTER TABLE user_training CHANGE training_status_id training_status_id INT DEFAULT 1)

迁移代码：

Schema::table('user_training', function ($table) {
           $table->dropForeign('fk_user_training_training_status1_idx');
           $table->integer('training_status_id')->default(1)->change();
           $table->foreign('training_status_id', 'fk_user_training_training_status1_idx')
               ->references('id')->on('training_status')
               ->onDelete('set null')
               ->onUpdate('cascade');
        });

Answer 1

可能是因为你的数据库有数据，可以使用disableForeignKeyConstraints();忽略约束：

Public up function(){
Schema::disableForeignKeyConstraints();

Schema::table('user_training', function ($table) {
           $table->dropForeign('fk_user_training_training_status1_idx');
           $table->integer('training_status_id')->default(1)->change();
           $table->foreign('training_status_id', 'fk_user_training_training_status1_idx')
               ->references('id')->on('training_status')
               ->onDelete('set null')
               ->onUpdate('cascade');
        });

Schema::enableForeignKeyConstraints();
}

Answer 2

列“training_status.id”无符号，因此列“user_training.training_status_id”也必须无符号 ，所以我需要指定修饰符“unsigned()”。此外，在这种情况下，迁移中不需要删除并重新创建外键：

Schema::table('user_training', function ($table) {
           $table->integer('training_status_id')->default(1)->unsigned()->change();
        });

Laravel 迁移：使用外键更改列

Laravel migration: Alter column with foreign key

migration

laravel