PHP 7.x SQLITE3 PDO - is the execute() closing the PDO connection? - php

Question

I have this code that works weird with SQLITE3 , since the same code with MYSQL works fine
The issue is the line commented with "ISSUE" at line #31, because with MYSQL/MariaDB that "re connection" is NOT needed
Now I better explain
If the IF routine is not entered, I have NO error
If the IF routine is processed, line #34 throws
Uncaught Error: Call to undefined method PDOStatement::prepare()
like if the $PDO-execute(); inside the IF is destroying the PDO istance
You may say, well, no problem, now you have fixed it ... yes, but I'd like to understand why this happen.
Also portability is a point. If this is PDO ... except for the connection, the rest of the script should work and moved among various supported PDO DBs
Thank you if you kindly hint what is the reason and what is it
<?php
// Create or open a database file
$PDO = new PDO('sqlite:myDatabase.sqlite3');
if( isset($_POST['NoteUpdateText']) && !empty(trim($_POST['NoteUpdateText'])) ){
//$testo = $_POST['NoteUpdateText'];
try {
$PDO = $PDO->prepare('UPDATE ajax SET testo = :testo WHERE id = :id');
$PDO->bindValue(':testo', $_POST['NoteUpdateText']);
$PDO->bindValue(':id', 1);
$PDO->execute();
// echo a message to say the UPDATE succeeded
//echo $stmt->rowCount() . " records UPDATED successfully";
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
}
// In EVERY case, load the actual DB record and return it to javascript
$PDO = new PDO('sqlite:myDatabase.sqlite3'); // --- ISSUE, theoretically this is already opened at line #3 ---
try {
$PDO = $PDO->prepare('SELECT testo FROM ajax WHERE id=1 LIMIT 1');
$PDO->execute();
$row = $PDO->fetch();
//var_dump($row);
echo $row["testo"];
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
?>
FIXED CODE
<?php
//include 'db-con2.php';
// table: ajax
// col: testo
// Create or open a database file
$PDO = new PDO('sqlite:myDatabase.sqlite3');
if( isset($_POST['NoteUpdateText']) && !empty(trim($_POST['NoteUpdateText'])) ){
//$testo = $_POST['NoteUpdateText'];
try {
$statement = $PDO->prepare('UPDATE ajax SET testo = :testo WHERE id = :id');
$statement->bindValue(':testo', $_POST['NoteUpdateText']);
$statement->bindValue(':id', 1);
$statement->execute();
// echo a message to say the UPDATE succeeded
//echo $stmt->rowCount() . " records UPDATED successfully";
}
catch(PDOException $e)
{
echo $sql . "<br> - IF -" . $e->getMessage();
}
}
// carica da DB in ogni caso per caricare il P col testo realmente in DB
//$PDO = new PDO('sqlite:myDatabase.sqlite3');
try {
$statement = $PDO->prepare('SELECT testo FROM ajax WHERE id=1 LIMIT 1');
$statement->execute();
$row = $statement->fetch();
//var_dump($row);
echo $row["testo"];
}
catch(PDOException $e)
{
echo $sql . "<br> - NORMALE - " . $e->getMessage();
}
?>

Answer 1

Why would you override $PDO variable ?
$pdo = new PDO('sqlite:myDatabase.sqlite3');
if( isset($_POST['NoteUpdateText']) && !empty(trim($_POST['NoteUpdateText'])) ){
//$testo = $_POST['NoteUpdateText'];
try {
$stmt = $PDO->prepare('UPDATE ajax SET testo = :testo WHERE id = :id');
if ($stmt->execute(array(':testo'=>$_POST['NoteUpdateText'], ':id' => 1)))
{
// echo a message to say the UPDATE succeeded
//echo $stmt->rowCount() . " records UPDATED successfully";
} else {
// There's error processing updates
// debug
print_r($stmt->errorInfo());
}
} catch(PDOException $e) {
echo $sql . "<br>" . $e->getMessage();
}
}
// In EVERY case, load the actual DB record and return it to javascript
// There's no need to redeclare $PDO
// $PDO = new PDO('sqlite:myDatabase.sqlite3'); // --- ISSUE, theoretically this is already opened at line #3 ---
try {
$stmt = $pdo->prepare("SELECT testo FROM ajax WHERE id=1 LIMIT 1"); // line #34
$stmt->execute();
$row = $stmt->fetch();
//var_dump($row);
echo $row["testo"];
} catch(PDOException $e) {
echo $sql . "<br>" . $e->getMessage();
}