Codeigniter使用joins表删除数据

Question

从逻辑上讲，在SQL中，我们可以使用连接从表中删除数据，例如

DELETE  clb_subscriber_group_mapping .* FROM clb_subscriber_group_mapping 
INNER JOIN clb_driver_group ON (clb_driver_group.id = clb_subscriber_group_mapping.driver_group_id)
INNER JOIN clb_company ON (clb_company.id = clb_driver_group.company_id)
WHERE clb_company.id = 256 AND clb_subscriber_group_mapping.subscriber_id = 1784;

上述查询的CodeIgniter等效项是什么？

CodeIgniter是否支持使用joins删除查询？

Answer 1

你必须使用Active Records吗？

下面的query将做不同的事情。

$int_company_id = 256;
$int_subscriber_id = 1784;

$this->db->query("
DELETE  clb_subscriber_group_mapping .* FROM clb_subscriber_group_mapping 
INNER JOIN clb_driver_group ON (clb_driver_group.id = clb_subscriber_group_mapping.driver_group_id)
INNER JOIN clb_company ON (clb_company.id = clb_driver_group.company_id)
WHERE clb_company.id = ? AND clb_subscriber_group_mapping.subscriber_id = ?;

", array($int_company_id, $int_subscriber_id));

Answer 2

使用CodeIgniter的活动记录类不能做到这一点。它不支持delete查询中的连接。您必须使用Robin Castlin提到的$this->db->query()执行查询。

下面的代码取自核心文件。它是生成DELETE查询的内部组件之一。

function _delete($table, $where = array(), $like = array(), $limit = FALSE)
{
    $conditions = '';

    if (count($where) > 0 OR count($like) > 0)
    {
        $conditions = "\nWHERE ";
        $conditions .= implode("\n", $this->ar_where);

        if (count($where) > 0 && count($like) > 0)
        {
            $conditions .= " AND ";
        }
        $conditions .= implode("\n", $like);
    }

    $limit = ( ! $limit) ? '' : ' LIMIT '.$limit;

    return "DELETE FROM ".$table.$conditions.$limit;
}

正如您所看到的，其中没有指定插入JOIN子句的内容。

Answer 3

我也遇到了同样的问题，连接被忽略了：

$r1 = $db->where("object2_type", $object_type)
->join($object_type, "$object_type.id = object1_id", "LEFT")
->where("$object_type.id IS NULL", null, false)
->delete("knots");

所以我是这样做的：

$ids = $db->select("knots.id")
->where("object2_type", $object_type)
->join($object_type, "$object_type.id = object1_id", "LEFT")
->where("$object_type.id IS NULL", null, false)
->get("knots")->result_object();
/* my ow function which generates a string like '1','2','3' or 0 */    
$ids_csv = $this->mh()->get_flat_items_as_csv($ids);
$r = $db->where("knots.id IN ($ids_csv)", null, false)->delete("knots);