php - 数据库错误 1452

Question

我正在开发这个项目，该项目在两个表上都有外键。通过使用表单，我尝试将新记录插入数据库。数据库中还有一个图像路径，我通过表单插入图像路径。我正在使用 codeigniter 文件上传库。当我提交表单时，数据库表的其他字段甚至外键字段都会更新。但图像路径没有更新。当我提交表单时，它显示此错误。

A Database Error Occurred

Error Number: 1452

Cannot add or update a child row: a foreign key constraint fails (`bfh`.`products`, CONSTRAINT `category_fk` FOREIGN KEY (`category_id`) REFERENCES `categories` (`id`))

INSERT INTO `products` (`img`) VALUES ('assets/img//sakya.PNG')

Filename: C:/xampp/htdocs/CI-skeleton/system/database/DB_driver.php

Line Number: 691

Controller

public function add_product()
    {
        $result = 0;
        $cat_id = $this->input->post("category_id");
        $type_id    = $this->input->post("type_id");
        $pname  = $this->input->post("p_name");
        $images = $this->input->post("images");
        $images  = $_FILES['images']['name'];
        $price  = $this->input->post("price");

        $this->load->model("Products_Model");
        $product_id = $this->Products_Model->add_product( $cat_id, $type_id, $pname, $price);

        if ($product_id != 0) {
        $result = $this->Products_Model->add_product_images($images);
        }


        if ($result && $_FILES['images']['name'][0] != "") {
        $this->load->model('Image_Upload');
        $result = $this->Image_Upload->upload("assets/img");
    }

        $this->session->set_flashdata('result', $result);
        redirect('Products');
    }

型号

public function add_product( $cat_id, $type_id, $pname, $price)
    {
        $result = $this->db->get_where("products", array('name' => $pname));
        if ($result->num_rows() != 0) {
            return 0; // record already exists
        } else {
            $data = array(
                    'category_id' => $cat_id,
                    'type_id' => $type_id,
                    'name' => $pname,
                    'price' => $price
            );

            if( !$this->db->insert('products', $data)) {
                return -1; // error
            }else{
                return $this->db->insert_id();
            }

            return 1; // success
        }
    }

public function add_product_images($images)
{
    $path = "assets/img/";

    foreach ($images as $image) {
        // if no images were given for the item
        if ($image == "") {
            return 1;
        }

        $data = array(
                'img' => $path."/".$image
        );

        if ( ! $this->db->insert('products', $data)) {
            return 0; // if something goes wrong
        }
    }

    return 1;
}

Answer 1

您应该使用“更新”查询来代替 add_product_images() 中的插入。因为“插入”将添加产品的新记录，并且没有任何类别 id(外键)，这就是显示此错误的原因。所以尝试更新图像。