多对多关联设置中间表模型

增加wherePivot方法

library/think/model/relation/BelongsToMany.php

@@ -20,9 +20,12 @@ use think\model\Relation;
 
 class BelongsToMany extends Relation
 {
-    // 中间表模型
+    // 中间表表名
     protected $middle;
 
+    // 中间表模型
+    protected $pivot;
+
     /**
      * 构造函数
      * @access public
@@ -42,6 +45,28 @@ class BelongsToMany extends Relation
         $this->query      = (new $model)->db();
     }
 
+    /**
+     * 设置中间表模型
+     * @param $pivot
+     * @return $this
+     */
+    public function pivot($pivot)
+    {
+        $this->pivot = $pivot;
+        return $this;
+    }
+
+    /**
+     * 实例化中间表模型
+     * @param $data
+     * @return mixed
+     */
+    protected function newPivot($data)
+    {
+        $pivot = $this->pivot ?: '\\think\\model\\Pivot';
+        return new $pivot($data, $this->middle);
+    }
+
     /**
      * 延迟获取关联数据
      * @param string   $subRelation 子关联名
@@ -54,7 +79,7 @@ class BelongsToMany extends Relation
         $localKey   = $this->localKey;
         $middle     = $this->middle;
         if ($closure) {
-            call_user_func_array($closure, [ & $this->query]);
+            call_user_func_array($closure, [& $this->query]);
         }
         // 关联查询
         $pk                              = $this->parent->getPk();
@@ -71,7 +96,7 @@ class BelongsToMany extends Relation
                     }
                 }
             }
-            $set->pivot = new Pivot($pivot, $this->middle);
+            $set->pivot = $this->newPivot($pivot);
         }
         return $result;
     }
@@ -95,12 +120,27 @@ class BelongsToMany extends Relation
      * @access public
      * @param mixed $where 查询条件（数组或者闭包）
      * @return Query
+     * @throws Exception
      */
     public function hasWhere($where = [])
     {
         throw new Exception('relation not support: hasWhere');
     }
 
+    /**
+     * 设置中间表的查询条件
+     * @param      $field
+     * @param null $op
+     * @param null $condition
+     * @return $this
+     */
+    public function wherePivot($field, $op = null, $condition = null)
+    {
+        $field = 'pivot.' . $field;
+        $this->query->where($field, $op, $condition);
+        return $this;
+    }
+
     /**
      * 预载入关联查询（数据集）
      * @access public
@@ -230,7 +270,7 @@ class BelongsToMany extends Relation
                     }
                 }
             }
-            $set->pivot                      = new Pivot($pivot, $this->middle);
+            $set->pivot                      = $this->newPivot($pivot);
             $data[$pivot[$this->localKey]][] = $set;
         }
         return $data;
@@ -327,7 +367,7 @@ class BelongsToMany extends Relation
             foreach ($ids as $id) {
                 $pivot[$this->foreignKey] = $id;
                 $this->query->table($this->middle)->insert($pivot, true);
-                $result[] = new Pivot($pivot, $this->middle);
+                $result[] = $this->newPivot($pivot);
             }
             if (count($result) == 1) {
                 // 返回中间表模型对象