thinkphp 关联

男娘i 2021-11-02 07:58 266阅读 0赞

原理：[https://www.kancloud.cn/laowu199/e\_dev/448632][https_www.kancloud.cn_laowu199_e_dev_448632]

示例数据库

![1528244-20190730185817085-7647476.png][]

![1528244-20190730190101289-1101222554.png][]

![1528244-20190730185752418-2124816571.png][]

hasOne：有一个，加上主谓语应该是 ，A 有一个 B  
hasMany：有很多，A 有很多 B

<?php
    namespace app\common\model;
    use think\facade\Log;
    use think\Model;
    class CategoryModel extends App
    {
        protected $table ='category';
        protected $pk = 'id';
        
        public function product(){
            return $this->hasMany("app\common\model\ProductModel",'category_id','id')->order('id'); 
        //注意第二个参数为外键,第三个参数为CategoryModel里面对应外键的域
    }

调用

$categorys =  CategoryModel::with(['product'=>function($query){
        $query->field('id,name,product_code,price1,price2,category_id');}])->all();

参考

$list = User::field('id,name')->with(['profile'=>function($query){
        $query->field('email,phone');}])->select([1,2,3]);
    //如果使用field方法指定查询字段，闭包函数内查询字段必须包含当前关联模型的主键，否则会导致关联查询失败
    foreach($list as $user){
    // 获取用户关联的profile模型数据
    dump($user->profile);
    }

belongsTo：属于， A 属于 B

数据表

model

<?php
    
    
    namespace app\common\model;
    
    
    use think\Model;
    
    class ProductModel extends Model
    {
        protected $table = 'product';
        protected $pk = 'id';
    
    
    
        public function category(){
            return $this->belongsTo('app\common\model\CategoryModel','category_id','id');
        }
        public function getProductByCategory($categoryId = 0){
            return $this->where('id',$categoryId)->select();
        }
    
    
    }

调用

$productModel = new ProductModel();
            $product = $productModel::find(5); //注意关联查询只能单条数据查询
            $category= $product->category;
    
            dump($product);

belongsto输出

hasMany调用

$categoryDao = new CategoryModel();
           $category = $categoryDao::get(1);
           $product = $category->product;

转载于:https://www.cnblogs.com/jiangfeilong/p/11264806.html

[https_www.kancloud.cn_laowu199_e_dev_448632]: https://www.kancloud.cn/laowu199/e_dev/448632
[1528244-20190730185817085-7647476.png]: /images/20211101/2cb979e9f48a43f6908e2334a61113e8.png
[1528244-20190730190101289-1101222554.png]: /images/20211101/66105bb181954ff38ca1a0789f2ae5a4.png
[1528244-20190730185752418-2124816571.png]: /images/20211101/bd1652c6739a423b8d66da944f6b33d6.png