php - Laravel 改变外键约束

Question

我有一个已经创建外键约束的表:

$table->foreign('cms_id')->references('id')->on('inventories');

我需要更改此外键，以便它引用 remote_id 而不是 inventories 表中的 id 列。

我已经尝试这样做了:

    public function up()
    {
        Schema::table('contents', function (Blueprint $table) {
            $table->dropForeign('contents_cms_id_foreign');
            $table->foreign('cms_id')->references('remote_id')->on('inventories');
        });
    }

但是，我得到:

[Illuminate\Database\QueryException]
SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL : alter table contents add constraint contents_cms_id_foreign foreign k ey (cms_id) references inventories (remote_id))

[PDOException]
SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint

Answer 1

分两步添加新的外键，除了分离到Schema::table:

public function up()
{
    Schema::table('contents', function (Blueprint $table) {
        $table->dropForeign('contents_cms_id_foreign');
        $table->integer('cmd_id')->unsigned();
    });

    Schema::table('contents', function (Blueprint $table) {
        $table->foreign('cms_id')->references('remote_id')->on('inventories');
    });
}