我的laravel应用程序中遇到了此错误。
这些是表格:
发布
Schema::create('posts', function (Blueprint $table) {
$table->increments('id');
$table->string('title');
$table->text('content');
$table->timestamps();
$table->integer('user_id')->unsigned();
});
类别
Schema::create('categories', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->timestamps();
});
Post_Category
Schema::create('post_category', function (Blueprint $table) {
$table->integer('post_id')->unsigned()->unique()->nullable();
$table->integer('cat_id')->unsigned()->unique()->nullable();
$table->timestamps();
});
外键
Schema::table('posts', function (Blueprint $table) {
$table->foreign('id')->references('post_id')->on('post_category')->onDelete('cascade');
});
Schema::table('categories', function (Blueprint $table) {
$table->foreign('id')->references('cat_id')->on('post_category')->onDelete('cascade');
});
这是我的模型
class Categorie extends Model
{
protected $table = 'categories';
public function posts() {
return $this->hasMany('AppPostCategory');
}
}
。
class Post extends Model
{
public function author() {
return $this->belongsTo('AppUser', 'user_id');
}
public function featuredImage() {
return $this->belongsTo('AppMedia', 'media_id');
}
public function categories() {
return $this->hasMany('AppPostCategory');
}
}
。
class PostCategory extends Model
{
protected $table = 'post_category';
}
这里的控制器
店铺类别:
public function store(StoreCategory $request)
{
$category = new Categorie;
$category->name = $request->input('name');
$category->save();
return redirect('/admin/categories')->with('status', 'New category created!');
}
商店帖子
public function store(StorePost $request)
{
$post = new Post;
$post->title = $request->input('title');
$post->content = $request->input('content');
$post->media_id = $request->input('media_id');
$post->user_id = $request->input('user_id');
$post->save();
return redirect('/admin/posts')->with('status', 'New post created!');
}
出现此错误
SQLSTATE[23000]: 完整性约束冲突: 1452 无法添加或更新子行: 外键约束失败 (
the_film_corner
.tfc_categories
, 约束categories_id_foreign
外键 (id
) 引用tfc_post_category
(cat_id
) 关于删除级联) (SQL: 插入tfc_categories
(name
,updated_at
,created_at
) 值 (新闻, 2017-02-26 14:51:15, 2017-02-26 14:51:15))
谢谢
在错误的表中添加外键:
Schema::table('post_category', function(Blueprint $table) {
$table->foreign('post_id')->references('id')->on('post')->onDelete('cascade');
$table->foreign('category_id')->references('id')->on('category')->onDelete('cascade');
});
然后。。。
class Categorie extends Model
{
protected $table = 'categories';
public function posts() {
return $this->belongsToMany('AppCategory');
// Or more specifically
return $this->belongsToMany('AppCategory', 'post_category', 'id', 'post_id');
}
}
class Post extends Model
{
// ...
public function categories() {
return $this->belongsToMany('AppCategory');
// Or more specifically
return $this->belongsToMany('AppCategory', 'post_category', 'id', 'category_id');
}
}
您可以在以下Laravel官方指南中找到更多信息:
https://laravel.com/docs/5.4/eloquent-relationships#one-to-many
错误说明了一切。通过此设置,在将行插入tfc_categories
之前,列id
的值必须存在于表tfc_post_category
的列cat_id
中。否则,您将违反失败消息中提到的约束。
但我宁愿猜测您希望一列引用另一列,反之亦然。