为什么在Laravel 5.8中创建外键失败? [英] Why is creating Foreign Key in Laravel 5.8 failing?
问题描述
下面的迁移脚本在旧版本的Laravel中运行平稳,但是我将其添加到了新的Laravel 5.8中并运行了该脚本.我正在Error: foreign key was not formed correctly
The migration script below was running smoothly in an older version of Laravel but I added it to my fresh Laravel 5.8 and ran the script. I'm getting Error: foreign key was not formed correctly
评估迁移:
public function up() {
Schema::create('evaluation', function (Blueprint $table) {
$table->increments('id');
$table->integer('user_id')->unsigned()->index();
$table->timestamps();
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});
}
用户迁移:
public function up() {
Schema::create('users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->timestamps();
});
}
推荐答案
正如我们在上面的注释中所讨论的,外键列必须与它所引用的主键具有相同的数据类型.
As we discussed in the comments above, a foreign key column must be the same data type as the primary key it references.
您将user.id
主键声明为$table->bigIncrements('id')
,它在MySQL语法中变为BIGINT UNSIGNED AUTO_INCREMENT
.
You declared your user.id
primary key as $table->bigIncrements('id')
which becomes BIGINT UNSIGNED AUTO_INCREMENT
in MySQL syntax.
必须将外键声明为$table->unsignedBigInteger('user_id')
,在MySQL中将变为BIGINT UNSIGNED
,使其与user.id
列的外键兼容.
You must declare the foreign key as $table->unsignedBigInteger('user_id')
which will become BIGINT UNSIGNED
in MySQL, making it compatible with being a foreign key to the user.id
column.
这篇关于为什么在Laravel 5.8中创建外键失败?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!