20.Yii2.0框架多表关联一对多查询之hasMany

目录

• [TOC]

新手模式

用上次的查询结果,作为本次的查询条件

    //关联查询
    public function actionRelatesearch(){
        //新手模式
        $category = Category::findOne(2); //查分类表里的数据 abj
        $categoryarr = $category->attributes; //获取某一行的分类结果里的对象属性,array
        dump($categoryarr);

        //查文章里的cid等于2的 拿上面的结果 $categoryarr['cid']=2 作为本次查询的条件
        $article = Article::find()->asArray()->where(['cid'=>$categoryarr['cid']])->all();
        dump($article); //返回的是二维数组arr
    }

结果:

Array
(
    [cid] => 2
    [c_name] => 娱乐
)

Array
(
    [0] => Array
        (
            [article_id] => 6
            [article_title] => php的发展前景怎样
            [num] => 8
            [cid] => 2
        )

    [1] => Array
        (
            [article_id] => 7
            [article_title] => 67岁宋春丽与聂远出新戏，满头花发让人心疼，面容慈祥豪爽依旧！
            [num] => 12
            [cid] => 2
        )

    [2] => Array
        (
            [article_id] => 8
            [article_title] => 知微又涨粉啦！《天盛长歌》小衣衣、楚王和金狮王子你会选谁？
            [num] => 18
            [cid] => 2
        )

    [3] => Array
        (
            [article_id] => 9
            [article_title] => 刘亦菲穿旗袍带仙气，赵丽颖穿旗袍优雅，她穿旗袍最有民国范
            [num] => 14
            [cid] => 2
        )

)

---

hasMany关联模式查询

思路

1.用category表里查一行,查出某一个分类下的所有字段 结果是一维数组下的值是obj

2.查出来的结果,用hasMany()去关联查询article表里的关联字段cate_id查询出属于该分类下的所有数据,用all()方法查多行

新建mode层Article.php

<?php
namespace app\models;

use yii\db\ActiveRecord;

class Article extends ActiveRecord
{

}

新建mode层Category.php

<?php
namespace app\models;

use yii\db\ActiveRecord;

class Category extends ActiveRecord
{

}

新建控制器HomeController.php

    public function actionRelatesearch(){
        //关联查询
        //查询方法一(查一行) 一维数组下的值是obj
//        $category = Category::findOne(1); //查分类表里的数据 abj
////        vp($category);
//        $articles = $category->hasMany(Article::className(),['cate_id'=>'cid'])->asArray()->all();
//        dd($articles);

        //查询方法二(查多行,结果需要提出一行来使用):
        //查分类表里的数据要是一维数组下的值是obj 不能用asArray()转为数组,不然hasMany会报错
        $category = Category::find()->where(['cid'=>2])->all();
        vp($category);
        //关联查询 用hasMany方法前提要满足二个条件
        //1.如果查出来是二维数组需要用角标提成一维数组
        //2.主表category 表查出来的结果要是一维数组下的值是obj 不能用asArray转成数组
        //第一个参数是string article的命名空间app/models/Article == Article::className()
        vp(Article::className()); //打印结果app/models/Article
        //第二个参数是array key是article表里的关联字段 value是category里的主键
        $articles = $category[0]->hasMany(Article::className(),['cate_id'=>'cid'])->asArray()->all();
        dd($articles);
    }

打印结果

D:\xampp\htdocs\yii\helper\function.php:19:
array (size=1)
  0 =>
    object(app\models\Category)[78]
      private '_attributes' (yii\db\BaseActiveRecord) =>
        array (size=2)
          'cid' => string '2' (length=1)
          'c_name' => string '娱乐' (length=6)
      private '_oldAttributes' (yii\db\BaseActiveRecord) =>
        array (size=2)
          'cid' => string '2' (length=1)
          'c_name' => string '娱乐' (length=6)
      private '_related' (yii\db\BaseActiveRecord) =>
        array (size=0)
          empty
      private '_relationsDependencies' (yii\db\BaseActiveRecord) =>
        array (size=0)
          empty
      private '_errors' (yii\base\Model) => null
      private '_validators' (yii\base\Model) => null
      private '_scenario' (yii\base\Model) => string 'default' (length=7)
      private '_events' (yii\base\Component) =>
        array (size=0)
          empty
      private '_eventWildcards' (yii\base\Component) =>
        array (size=0)
          empty
      private '_behaviors' (yii\base\Component) =>
        array (size=0)
          empty

D:\xampp\htdocs\yii\helper\function.php:19:string 'app\models\Article' (length=18)

D:\xampp\htdocs\yii\helper\function.php:26:
array (size=4)
  0 =>
    array (size=4)
      'article_id' => string '6' (length=1)
      'article_title' => string 'php的发展前景怎样' (length=24)
      'num' => string '8' (length=1)
      'cate_id' => string '2' (length=1)
  1 =>
    array (size=4)
      'article_id' => string '7' (length=1)
      'article_title' => string '67岁宋春丽与聂远出新戏，满头花发让人心疼，面容慈祥豪爽依旧！' (length=89)
      'num' => string '12' (length=2)
      'cate_id' => string '2' (length=1)
  2 =>
    array (size=4)
      'article_id' => string '8' (length=1)
      'article_title' => string '知微又涨粉啦！《天盛长歌》小衣衣、楚王和金狮王子你会选谁？' (length=87)
      'num' => string '18' (length=2)
      'cate_id' => string '2' (length=1)
  3 =>
    array (size=4)
      'article_id' => string '9' (length=1)
      'article_title' => string '刘亦菲穿旗袍带仙气，赵丽颖穿旗袍优雅，她穿旗袍最有民国范' (length=84)
      'num' => string '14' (length=2)
      'cate_id' => string '2' (length=1)