当准备好的查询省略 NOT NULL 字段时，PostgreSQL PHP PDO 执行挂起

Question

使用 PostgreSQL 9.6 和 PHP 7.2，我正在创建一个 PDO 连接，准备一个 INSERT 查询，绑定参数，然后执行准备好的查询。我将ATTR_ERRMODE 设置为ERRMODE_EXCEPTION，实际上可能会导致执行抛出异常，例如，准备好的查询有4 个参数，但我只绑定了3 个。

但是，如果我准备好的查询不包含具有 NOT NULL 约束的字段，则执行可能会挂起 20 秒，然后浏览器会显示“连接已重置”。 Postgres 日志说：

ERROR:  null value in column "fullname" violates not-null constraint
DETAIL:  Failing row contains (345, fredf, fredf@bedrock.net, yabadabadoo, null, Bedrock, none, user).
STATEMENT:  INSERT INTO users (username, password, location, description, email, role) VALUES ($1, $2, $3, $4, $5, $6)
LOG:  could not receive data from client: An existing connection was forcibly closed by the remote host.

这 4 个日志条目总共重复了 10 次。

我理解这种情况确实是一个编程问题——查询应该符合数据库设计的要求。但我真的很想哄 Postgres PDO 驱动程序告诉我错误是什么，而不是去挖掘日志。

---

示例代码

/*

Sample code to demonstrate failure of prepared query execute()
to throw an exception when the prepared query omits a field
with a NOT NULL constraint.

CREATE TABLE users (
  id                SERIAL PRIMARY KEY,
  username      varchar(50) NOT NULL,
  email           varchar(100) NOT NULL,
  password      varchar(255) NOT NULL,
  fullname      varchar(100) NOT NULL,
  location      varchar(100) NOT NULL,
  description text NOT NULL,
  role            varchar(50) NOT NULL DEFAULT ''
);

*/
    $host   = "localhost";  
    $user   = "postgres";  
    $pass   = "password";  
    $dbname = "database";  
    /**
     * Initialize the PDO connection. 
     */
        $dsn = 'pgsql:host=' . $host . ';dbname=' . $dbname;
        $options = [
            PDO::ATTR_PERSISTENT => true,  
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION  
            ]; 
        try {  
            $handler = new PDO($dsn, $user, $pass, $options);  
        } catch (PDOException $e) {  
            echo $e->getMessage();
            die();  
        } 

     /**
      * Demonstrate failure of execute() to return an error or throw an exception
      * Error condition omits the fullname field from the INSERT query, which has a 
      * "not null" constraint.
      */
        $demonstrateProblem = 1;

        $badQuery = "INSERT INTO users (username, password, location, description, email, role) " . 
                    "VALUES (:username, :password, :location, :description, :email, :role)";

        $goodQuery = "INSERT INTO users (username, password, fullname, location, description, email, role) " . 
                    "VALUES (:username, :password, :fullname, :location, :description, :email, :role)";

        if ($demonstrateProblem == 1) {
            $query = $badQuery;
        } else  {
            $query = $goodQuery;
        }

        $stmt = $handler->prepare($query);  
        if (!$stmt) {
            echo "Error in prepare, errorInfo():<br>";
            print_r($handler->errorInfo());
        }
    /**
     * Bind the variables
     */
        $username   = "fredf";
        $password   = "yabadabadoo";
        $fullname   = "Fred Flintstone";
        $location   = "Bedrock";
        $description = "none";
        $email      = "fredf@bedrock.net";
        $role       = "user";

        $stmt->bindParam(':username', $username);
        $stmt->bindParam(':password', $password);
        if ($demonstrateProblem == 0) {
            $stmt->bindParam(':fullname', $fullname);
        } else {
            // nothing to do, :fullname is not in the prepared query!
        }
        $stmt->bindParam(':location', $location);
        $stmt->bindParam(':description', $description);
        $stmt->bindParam(':email', $email);
        $stmt->bindParam(':role', $role);
    /**
     * Execute a prepared statement.
     */
        echo "Executing prepared query...<br>";
        try {
            $res = $stmt->execute(); // <-- this statement hangs when the query prepare is bad.
            if ($res) {
                echo "execute returns true<br> ";
            } else {
                echo "execute returns false<br> ";               
            }
        } catch (PDOException $e) {  
            echo "execute error " . $e->getMessage();  // <-- this never appears
        }

PostgreSQL 日志（序列重复 10 次）

 ERROR:  null value in column "fullname" violates not-null constraint
 DETAIL:  Failing row contains (345, fredf, fredf@bedrock.net, yabadabadoo, null, Bedrock, none, user).
 STATEMENT:  INSERT INTO users (username, password, location, description, email, role) VALUES ($1, $2, $3, $4, $5, $6)
 LOG:  could not receive data from client: An existing connection was forcibly closed by the remote host.

Answer 1

好吧，您正在尝试为具有 NOT NULL 约束的字段添加具有 NULL 值的数据。您要么需要在 Postgresql 中为“fullname”列定义默认值，要么将其设为 NULL。

Answer 2

我认为，您需要将准备语句和绑定参数代码放入 try 块中。 希望能解决问题。

Answer 3

请找出我使用的代码。

$host   = "";             
$user   = "";     
$pass   = "";         
$dbname = "";        
/**
 * Initialize the PDO connection. 
 */
    $dsn = 'pgsql:host=' . $host . ';dbname=' . $dbname;
    $options = [
        PDO::ATTR_PERSISTENT => true,
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
        ];
    try {
        $handler = new PDO($dsn, $user, $pass, $options);
    } catch (PDOException $e) {
        echo $e->getMessage();
        die();
    }


try{
$query = "insert into ********  values(null, 2709651, NOW(), 'test')";             
$stmt = $handler->prepare($query);
$res = $stmt->execute();
if ($res) {
            echo "execute returns true<br> ";
        } else {
            echo "execute returns false<br> ";
        }
}catch(PDOException $e){
echo $e->getMessage();
}

您可以尝试使用此代码。由于我在将 null 插入非 null 列时遇到错误。

SQLSTATE[23502]：非空违规：7 错误：“*******”列中的空值违反非空约束 详细信息：失败行包含 (null, 2709651, 2018-09-13 12:07:03.356125, test)。

这个错误来自异常处理。