thinkphp about the use of model one-to-many, many-to-many, many-to-one

First look at the model introduction of thinkphp5.0

There are one-to-one, many-to-many, one-to-many, and many-to-one associations here. There is also pre-loading (that is, the query is pre-written, and it is queried when the php interface is called), as well as related statistics, aggregation, etc. Here we only explain how to launch others through one-to-one preloading.

This document gives an example of a one-to-one relationship between Profile and User.

Model layer

Profile has a foreign key ($foreignKey) uid associated with User id, because id is the default field, you don’t need to write it, so the relationship is written like this

class Profile extends Model{
    public functionuser(){
        return $this->belongsTo('User','uid');
    }
}

It can also be written in this way, which is equivalent to select * from user where id = (?1), ?1 is the uid of the detected Profile, and the value is assigned to it, which is equivalent to two queries, one querying Profile, and then querying User

class Profile extends Model{
    public functionuser(){
        return $this->belongsTo('User','uid'，'id');
    }
}

control layer

$profile = Profile::get(1);

Here $profile gets all the fields (including uid (? 1)), which is equivalent to select * from profile. The first layer of query. Then the belongsTo query can continue (select * from user where id = (?1))

Practical

Write control layer (first layer query)

$question = new Question();
$lists = $question->field('id,question_category,name,right_num,"show",content')
->with('questionCategory1')
->order('create_time asc')
->paginate($this->web_data['list_rows'], false, $page_param);
$this->assign([
    'lists' => $lists,
    'page'  => $lists->render(),
    'total' => $lists->total()
]);

The focus is on the question_category in the field, where the foreign key is queried to prepare for the preloaded subquery

inside with is the name of the preloaded method and the name of the attribute to be called, for example, questionCategory1 in this article.

Write view layer (second layer call)

{foreach name="lists" item="list"}
<tr>
    <td><input type="checkbox" onclick="check_this(this)" name="data-checkbox"
               data-id="{$list.id}" class="checkbox data-list-check" value="{$list.id}"
               placeholder="选择/取消"></td>
    <td>{$list.id}</td>
    </td>
    <td>{$list.name}</td>
    <td>{$list.content}</td>
    <td>{$list.right_num}</td>
    <td>{$list->questionCategory1['title']}</td>
    <td>
        {if condition="$list.show eq '1'"}已显示
        {else /} 已隐藏
        {/if}
    </td>
    <td>
        {if condition="$list.show eq '1'"}
            <a href="{:url($web_data['do_url'].'unground','id='.$list.id)}"
               class="btn btn-default btn-sm margin">
                <i class="fa fa-edit"></i>
                隐藏
            </a>
        {else /}
            <a href="{:url($web_data['do_url'].'detail','id='.$list.id)}"
               class="btn btn-default btn-sm margin">
                <i class="fa fa-edit"></i>
                修改
            </a>
            <a href="{:url($web_data['do_url'].'ground','id='.$list.id)}"
               class="btn btn-default btn-sm margin">
                <i class="fa fa-edit"></i>
               显示
            </a>
            <a data-toggle="modal" data-target="#modal"
               class="btn btn-danger btn-sm margin"
               title="删除" onclick="del({$list.id})">
                <i class="fa fa-close"></i>
                删除
            </a>
        {/if}
    </td>
</tr>
{/foreach}

The ${lists} here is the parameter from the background transfer (assign), which is an object array, which is displayed on the interface through a loop.

{$list->questionCategory1['title']} is to call the questionCategory1 method to get the title attribute inside, and this call triggers the preloading function

write model layer

Question

namespace app\common\model;

use think\Model;

class Question extends Model
{
    protected $name = 'question';

    public function questionAnswer() {
        return $this->hasMany("QuestionAnswer", "question_id", "id");
    }
    
    //注意这里的questionCategory1特地加1是因为防止和和question_category的驼峰一致导致报错
    //这里field一定要查询出QuestionCategory的主键id，因为这个作为第二层查询的条件，如果去掉id会报错
    //这里的QuestionCategory的主键是id，question_category是Question的外键（关联QuestionCategory）
    public function questionCategory1()
    {
        return $this->belongsTo('QuestionCategory','question_category','id')->field('id,title');
    }
}

A: The preloading method of Question here is questionCategory1 (declaration), which matches with (preloading) of the control layer and also matches questionCategory1 (calling) of the view layer

B:然后从属关系，是一对一的QuestionCategory和Question，外键在Question上，外键名字是question_category，主键在QuestionCategory上的id

C:belongsTo的field代表Question这个模型的方法questionCategory1预加载了模型QuestionCategory的id和title属性，id作为第二次查询的条件和第一层查出来的question_category匹配作为条件

D:而且question_category不能和方法名驼峰一致。必须不相同。例如该方法的questionCategory和question_category相同会报错。所以改成了questionCategory1方法名

QuestionCategory

namespace app\common\model;
use think\Model;

class QuestionCategory extends Model
{
    protected $name = 'question_category';

}

同理推得一对多

    public function questionAnswer() {
        return $this->hasMany("QuestionAnswer", "question_id", "id");
    }

同理推理的一对一

 public function adminLogData()
    {
        return $this->hasOne('AdminLogData','log_id','id')->field('data_id,log_id,data');
    }

等等

thinkphp about the use of model one-to-many, many-to-many, many-to-one

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