Codeigniter Active Record JSON对象中的值 [英] Codeigniter Active Record where value in JSON object

问题描述

我有一个问题要问.首先，我有一个表，其中父母的 parent_id 为 0 ，而孩子的 parent_id 等于父母的id.所有子代的 parent_id 存储为json编码的数组(一个子记录可以有多个父代).

I have a question to ask. Firstly, I have a table, where the parent has parent_id is 0 and the child has parent_id equal parent id. parent_id of all children are stored as a json encoded array (one child record can have many parents).

因此，当我传递一个父母ID时，如何获得父母的所有孩子.我尝试了一下，但是它不起作用，我也没有任何头绪.

So, how can I get all the children of the parent when I pass one parent id. I tried but it won't work and I don't have a clue.

这是代码:

function get_child_product($parent_id, $limit, $start) {
        $this -> db -> from('product');
        $this -> db -> where(json_decode('parent_id'), $parent_id);
        $this -> db -> limit($limit, $start);
        $this -> db -> order_by('order', 'asc');
        $this -> db -> order_by('id', 'desc');
        $query = $this -> db -> get();
        return $query -> result();
    }

问题已解决:

function get_child_product($parent_id, $limit, $start) {
        $this -> db -> from('product');
        $this -> db -> like('parent_id', '"' . $parent_id . '"');
        $this -> db -> limit($limit, $start);
        $this -> db -> order_by('order', 'asc');
        $this -> db -> order_by('id', 'desc');
        $query = $this -> db -> get();
        return $query -> result();
    }

推荐答案

如果我正确理解您的数据库中具有父关系的JSON编码数组，并且您只想获得某个父项的子级.事实是，数据库中的JSON对象只不过是字符串，您无法在查询中动态解码它们并使用where子句.

If I understand correctly you have a JSON encoded array in your database with the parent relationship and you want to get only children of a certain parent. The thing is that JSON objects in a database are nothing more than strings, you cannot dynamically decode them in the query and use a where clause.

您有两个选择:

1.查询所有孩子，然后使用PHP根据解码后的JSON对其进行过滤

1.Query all your children then use PHP to filter them based on the decoded JSON

2.使用mysql like 匹配json格式的字符串

2.Use mysql like to match a string in json format

function get_child_product($parent_id, $limit, $start) {
    return $this -> db -> from('product')
                    -> like('parent_id', '"parent_id":'.$parent_id)
                    -> limit($limit, $start)
                    -> order_by('order', 'asc')
                    -> order_by('id', 'desc')
                    -> get()
                    -> result();
}

请注意， like 参数应与JSON的语法匹配，因此，如果您将id包裹在"引号中，然后将其添加到参数中

Note that the like parameter should match the syntax of your JSON so if you're ids are wrapped in " quotes, then add them to the parameter

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