Question

我想在我的tbl_category中添加类别。在添加之前，我想检查类别名称是否已存在。我尝试以下代码，但它给了我

致命错误：未捕获的异常＆＃39; PDOException＆＃39;

带有消息

SQLSTATE [42000]：语法错误或访问冲突：1064您的SQL语法出错;

public function save_category($data) {
        $category_name = $data['category_name'];
        $category_description = $data['category_description'];
        $publication_status = $data['publication_status'];
        $sql =  "SELECT category_name FROM tbl_category WHERE category_name='$category_name' ";
        $result =  $this->pdo->query($sql);
        $num_rows= $result->fetchColumn();
        if($num_rows != 0) {
            echo 'Category already exist';
        }
        else {
            try {
            $query = "INSERT INTO tbl_category(category_name, category_description, publication_status) VALUES(:category_name, :category_description, :publication_status)";
            $stmt = $this->pdo->prepare($query);
            $stmt->bindParam(':category_name', $category_name, PDO::PARAM_STR);
            $stmt->bindParam(':category_description', $category_description, PDO::PARAM_STR);
            $stmt->bindParam(':publication_status', $publication_status, PDO::PARAM_INT);
            $stmt->execute();
            $message = "Save category information successfully";
            return $message;
            } catch (PDOException $e) {
            echo $e->getMessage();
            } 
        }

    }

Answer 1

哪个查询是选择或插入的错误？

尝试debugDumpParams function，看看它是否为您提供了任何线索：

$stmt->debugDumpParams();

Answer 2

Nishan，使用$ this-＆gt; pdo-＆gt;也可以选择。并为“rowCount（）”更改“fetchColumn（）”，查看正确的代码

public function save_category($data) {
    $category_name = $data['category_name'];
    $category_description = $data['category_description'];
    $publication_status = $data['publication_status'];
    $result = $this->pdo->prepare("SELECT category_name FROM tbl_category WHERE category_name='$category_name'");
    if($result->execute()){
    $num_rows= $result->rowCount();
    if($num_rows != 0) {
        echo 'Category already exist';
    }
    else {
        try {
        $query = "INSERT INTO tbl_category(category_name, category_description, publication_status) VALUES(:category_name, :category_description, :publication_status)";
        $stmt = $this->pdo->prepare($query);
        $stmt->bindParam(':category_name', $category_name, PDO::PARAM_STR);
        $stmt->bindParam(':category_description', $category_description, PDO::PARAM_STR);
        $stmt->bindParam(':publication_status', $publication_status, PDO::PARAM_INT);
        $stmt->execute();
        $message = "Save category information successfully";
        return $message;
        } catch (PDOException $e) {
        echo $e->getMessage();
        } 
    }
    } else {
        echo "error in select";
    }

}

检查类别名称是否已存在

2 个答案: