PDO general error when using fetch after insert - php

Question

I'm trying to fetch data from the db using fetchAll(), which works unless I try to do so right after an insert query. The error I keep getting is a "General error". I read online that this is a know issue:
It seems that if you do a $statement->query() with an INSERT statement and after that a $statement->fetch() you will get an exception saying: SQLSTATE[HY000]: General error. source
Is there any way to go around this?
My code
First I'm running an insert query:
INSERT INTO question (`qid`, `question`, `category`, `subcategory`, `explanation`, `answer_type`, `answer_options`, `answer_nav`, `answer_optional`) VALUES ('65', 'TEST', 'wisselvraag', 'wk 1 - wk 1', '<strong>Let op! Maak aantekening bij vraag.</strong>', 'yes_no', '{null,null}', '', '1')
private function get($columns = "*", $dump = false)
{
$this->select($columns);
$this->prepareSQL();
if ($dump === true) {
$this->dumpSQL();
return [];
}
$this->stmt = $this->getPdo()->prepare($this->query);
$this->stmt->execute();
$this->incrementAmountOfQueries();
return $this->stmt->fetchAll(\PDO::FETCH_ASSOC);
}
Right after doing that I run a SELECT query:
SELECT question.* FROM question JOIN questionlist_question ON questionlist_question.`question_id` = question.`id` WHERE question.`category` = 'wisselvraag' AND questionlist_question.`questionlist_id` = '7' ORDER BY question.`qid` DESC LIMIT 1
To
$this->stmt->execute();
$this->stmt->fetchAll(\PDO::FETCH_ASSOC);
My data. The fetchAll() seems to be the problem.
/**
* prepare an INSERT query
* #param array $data
* #return bool
*/
private function insert(Array $data)
{
$fields = "";
$values = "";
foreach ($data as $field => $value) {
$value = htmlentities($value);
$fields .= "`$field`, ";
$values .= "'$value', ";
}
$fields = trim($fields, ", ");
$values = trim($values, ", ");
$this->insert = "($fields) VALUES ($values)";
$this->incrementAmountOfQueries();
return $this->execute();
}
/**
* Execute a query
* #return bool
*/
private function execute()
{
$this->prepareSQL();
// print($this->query);
// exit;
$this->stmt = $this->getPdo()->prepare($this->query);
return $this->stmt->execute();
}
$This->stmt
$this->stmt is defined as $this->stmt = $this->getPdo()->prepare($this->query);
getPdo()
/**
* Get PDO instance
* #return \PDO
*/
private function getPdo()
{
if (!$this->pdo) {
try {
$this->pdo = new \PDO($this->dsn, $this->username, $this->password);
$this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
} catch (\Exception $err) {
print_r($err);
exit;
}
}
return $this->pdo;
}
$this->query
private function prepareSQL()
{
$sql = "";
if ($this->insert) {
if ($this->table) {
$sql .= "INSERT INTO " . $this->table;
$sql .= " " . $this->insert;
}
} else {
if ($this->select) $sql .= "SELECT " . $this->select;
if ($this->table) $sql .= " FROM " . $this->table;
if ($this->join) $sql .= " " . $this->join;
if ($this->where) $sql .= " " . $this->where;
if ($this->order) $sql .= " " . $this->order;
if ($this->limit) $sql .= " LIMIT " . $this->limit;
}
$this->query = $sql;
return $this;
}

Answer 1

Yes.
I suppose you are returning this value from a function. Well, return a statement instead. And then chain a fetchAll() to your function call later, if you need to get the rows. You won't believe how enormously flexible your function will become.
You can check an example section for this kind of function: all this stuff is available only thanks to a statement returned.
You may also would like to read my other article, Your first database wrapper's childhood diseases as I am sure your wrapper has other issues.