I'm in the process of refactoring my DAL and I will now start using mysqli and prepared statements. My first task is to use mysqli so I'm testing this now.
This is my DAL class. This is just part of the code I use:
class DAL {
private $mysqli;
(...)
// Create new mysqli object
private function conn() {
$this->mysqli = new mysqli($this->host, $this->username, $this->pwd, $this->dbname);
if(mysqli_connect_errno()) {
echo "Connection Failed: " . mysqli_connect_errno(); exit();
}
}
public function getRowByValue($table,$column, $value)
{
$this->conn();
$result = $this->mysqli->query("SELECT name FROM sl_store LIMIT 5");
$result->close();
}
When executing the mysqli query, I only get this result: Unable to query local database Query was empty.
I've tested the SQL code in Toad and it returns 5 rows.
So why am I getting this error / what am I doing wrong?
even if no processing on your query is needed (no variable interpretation etc.) it could be possible, that query() needs a string delimited with " instead of '. Just a guess because of this example from php.net
if (!$mysqli->query("SET #a:='this will not work'")) {
Related
Warning: mysqli::query(): Couldn't fetch mysqli in C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php on line 43
The following is my connection file:
<?php
if(!isset($_SESSION))
{
session_start();
}
// Create array to hold error messages (if any)
$ErrorMsgs = array();
// Create new mysql connection object
$DBConnect = #new mysqli("localhost","root#localhost",
NULL,"Ladle");
// Check to see if connection errno data member is not 0 (indicating an error)
if ($DBConnect->connect_errno) {
// Add error to errors array
$ErrorMsgs[]="The database server is not available.".
" Connect Error is ".$DBConnect->connect_errno." ".
$DBConnect->connect_error.".";
}
?>
This is my class:
<?php
class EventCalendar {
private $DBConnect = NULL;
function __construct() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
function __destruct() {
if (!$this->DBConnect->connect_error) {
$this->DBConnect->close();
}
}
function __wakeup() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
// Function to add events to Zodiac calendar
public function addEvent($Date, $Title, $Description) {
// Check to see if the required fields of Date and Title have been entered
if ((!empty($Date)) && (!empty($Title))) {
/* if all fields are complete then they are
inserted into the Zodiac event_calendar table */
$SQLString = "INSERT INTO tblSignUps".
" (EventDate, Title, Description) ".
" VALUES('$Date', '$Title', '".
$Description."')";
// Store query results in a variable
$QueryResult = $this->DBConnect->query($SQLString);
I'm not great with OOP PHP and I'm not sure why this error is being raised. I pulled this code from elsewhere and the only thing I changed was the #new mysqli parameters. Can anyone help me to understand what is going wrong?
Probably somewhere you have DBconnection->close(); and then some queries try to execute .
Hint: It's sometimes mistake to insert ...->close(); in __destruct() (because __destruct is event, after which there will be a need for execution of queries)
Reason of the error is wrong initialization of the mysqli object. True construction would be like this:
$DBConnect = new mysqli("localhost","root","","Ladle");
I had the same problem. I changed the localhost parameter in the mysqli object to '127.0.0.1' instead of writing 'localhost'. It worked; I’m not sure how or why.
$db_connection = new mysqli("127.0.0.1","root","","db_name");
Check if db name do not have "_" or "-"
that helps in my case
Warning: mysqli::query(): Couldn't fetch mysqli in C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php on line 43
The following is my connection file:
<?php
if(!isset($_SESSION))
{
session_start();
}
// Create array to hold error messages (if any)
$ErrorMsgs = array();
// Create new mysql connection object
$DBConnect = #new mysqli("localhost","root#localhost",
NULL,"Ladle");
// Check to see if connection errno data member is not 0 (indicating an error)
if ($DBConnect->connect_errno) {
// Add error to errors array
$ErrorMsgs[]="The database server is not available.".
" Connect Error is ".$DBConnect->connect_errno." ".
$DBConnect->connect_error.".";
}
?>
This is my class:
<?php
class EventCalendar {
private $DBConnect = NULL;
function __construct() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
function __destruct() {
if (!$this->DBConnect->connect_error) {
$this->DBConnect->close();
}
}
function __wakeup() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
// Function to add events to Zodiac calendar
public function addEvent($Date, $Title, $Description) {
// Check to see if the required fields of Date and Title have been entered
if ((!empty($Date)) && (!empty($Title))) {
/* if all fields are complete then they are
inserted into the Zodiac event_calendar table */
$SQLString = "INSERT INTO tblSignUps".
" (EventDate, Title, Description) ".
" VALUES('$Date', '$Title', '".
$Description."')";
// Store query results in a variable
$QueryResult = $this->DBConnect->query($SQLString);
I'm not great with OOP PHP and I'm not sure why this error is being raised. I pulled this code from elsewhere and the only thing I changed was the #new mysqli parameters. Can anyone help me to understand what is going wrong?
Probably somewhere you have DBconnection->close(); and then some queries try to execute .
Hint: It's sometimes mistake to insert ...->close(); in __destruct() (because __destruct is event, after which there will be a need for execution of queries)
Reason of the error is wrong initialization of the mysqli object. True construction would be like this:
$DBConnect = new mysqli("localhost","root","","Ladle");
I had the same problem. I changed the localhost parameter in the mysqli object to '127.0.0.1' instead of writing 'localhost'. It worked; I’m not sure how or why.
$db_connection = new mysqli("127.0.0.1","root","","db_name");
Check if db name do not have "_" or "-"
that helps in my case
Warning: mysqli::query(): Couldn't fetch mysqli in C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php on line 43
The following is my connection file:
<?php
if(!isset($_SESSION))
{
session_start();
}
// Create array to hold error messages (if any)
$ErrorMsgs = array();
// Create new mysql connection object
$DBConnect = #new mysqli("localhost","root#localhost",
NULL,"Ladle");
// Check to see if connection errno data member is not 0 (indicating an error)
if ($DBConnect->connect_errno) {
// Add error to errors array
$ErrorMsgs[]="The database server is not available.".
" Connect Error is ".$DBConnect->connect_errno." ".
$DBConnect->connect_error.".";
}
?>
This is my class:
<?php
class EventCalendar {
private $DBConnect = NULL;
function __construct() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
function __destruct() {
if (!$this->DBConnect->connect_error) {
$this->DBConnect->close();
}
}
function __wakeup() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
// Function to add events to Zodiac calendar
public function addEvent($Date, $Title, $Description) {
// Check to see if the required fields of Date and Title have been entered
if ((!empty($Date)) && (!empty($Title))) {
/* if all fields are complete then they are
inserted into the Zodiac event_calendar table */
$SQLString = "INSERT INTO tblSignUps".
" (EventDate, Title, Description) ".
" VALUES('$Date', '$Title', '".
$Description."')";
// Store query results in a variable
$QueryResult = $this->DBConnect->query($SQLString);
I'm not great with OOP PHP and I'm not sure why this error is being raised. I pulled this code from elsewhere and the only thing I changed was the #new mysqli parameters. Can anyone help me to understand what is going wrong?
Probably somewhere you have DBconnection->close(); and then some queries try to execute .
Hint: It's sometimes mistake to insert ...->close(); in __destruct() (because __destruct is event, after which there will be a need for execution of queries)
Reason of the error is wrong initialization of the mysqli object. True construction would be like this:
$DBConnect = new mysqli("localhost","root","","Ladle");
I had the same problem. I changed the localhost parameter in the mysqli object to '127.0.0.1' instead of writing 'localhost'. It worked; I’m not sure how or why.
$db_connection = new mysqli("127.0.0.1","root","","db_name");
Check if db name do not have "_" or "-"
that helps in my case
Warning: mysqli::query(): Couldn't fetch mysqli in C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php on line 43
The following is my connection file:
<?php
if(!isset($_SESSION))
{
session_start();
}
// Create array to hold error messages (if any)
$ErrorMsgs = array();
// Create new mysql connection object
$DBConnect = #new mysqli("localhost","root#localhost",
NULL,"Ladle");
// Check to see if connection errno data member is not 0 (indicating an error)
if ($DBConnect->connect_errno) {
// Add error to errors array
$ErrorMsgs[]="The database server is not available.".
" Connect Error is ".$DBConnect->connect_errno." ".
$DBConnect->connect_error.".";
}
?>
This is my class:
<?php
class EventCalendar {
private $DBConnect = NULL;
function __construct() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
function __destruct() {
if (!$this->DBConnect->connect_error) {
$this->DBConnect->close();
}
}
function __wakeup() {
// Include the database connection data
include("inc_LadleDB.php");
$this->DBConnect = $DBConnect;
}
// Function to add events to Zodiac calendar
public function addEvent($Date, $Title, $Description) {
// Check to see if the required fields of Date and Title have been entered
if ((!empty($Date)) && (!empty($Title))) {
/* if all fields are complete then they are
inserted into the Zodiac event_calendar table */
$SQLString = "INSERT INTO tblSignUps".
" (EventDate, Title, Description) ".
" VALUES('$Date', '$Title', '".
$Description."')";
// Store query results in a variable
$QueryResult = $this->DBConnect->query($SQLString);
I'm not great with OOP PHP and I'm not sure why this error is being raised. I pulled this code from elsewhere and the only thing I changed was the #new mysqli parameters. Can anyone help me to understand what is going wrong?
Probably somewhere you have DBconnection->close(); and then some queries try to execute .
Hint: It's sometimes mistake to insert ...->close(); in __destruct() (because __destruct is event, after which there will be a need for execution of queries)
Reason of the error is wrong initialization of the mysqli object. True construction would be like this:
$DBConnect = new mysqli("localhost","root","","Ladle");
I had the same problem. I changed the localhost parameter in the mysqli object to '127.0.0.1' instead of writing 'localhost'. It worked; I’m not sure how or why.
$db_connection = new mysqli("127.0.0.1","root","","db_name");
Check if db name do not have "_" or "-"
that helps in my case
I need to do continuous parsing of several external stomp data streams, inserts of relevant fields into a MySql db, and regular queries from the db. All of this is in a protected environment - ie I'm not dealing with web forms or user inputs
Because I'm implementing a range of inserts into + queries from different tables, I've decided to set up a PDO active record model - following the advice of Nicholas Huot and many SO contributors.
I've got a simple repeated insert working OK, but after several days of grief can't get a prepared insert to fly. I want to use prepared inserts given there are going to be a lot of these (ie for performance).
Relevant bits of the code are :
=========
Database class :
private function __construct()
{
try {
// Some extra bad whitespace removed around =
$this->dbo = new PDO('mysql:host=' . DBHOST . ';dbname=' . DBNAME, DBUSER, DBPSW, $options);
} catch (PDOException $e) {
echo 'Connection failed: ' . $e->getMessage();
}
}
public static function getInstance()
{
if(!self::$instance)
{
self::$instance = new self();
}
return self::$instance;
}
public function prepQuery($sql) // prepared statements
{
try {
$dbo = database::getInstance();
$stmt = new PDOStatement();
$dbo->stmt = $this->$dbo->prepare($sql);
var_dump($dbo);
}
catch (PDOException $e) {
echo "PDO prepare failed : ".$e->getMessage();
}
}
public function execQuery($sql) // nb uses PDO execute
{
try {
$this->results = $this->dbo->execute($sql);
}
catch (PDOException $e) {
echo "PDO prepared Execute failed : \n";
var_dump(PDOException);
}
}
=========
Table class :
function storeprep() // prepares write to db. NB prep returns PDOstatement
{
$dbo = database::getInstance();
$sql = $this->buildQuery('storeprep');
$dbo->prepQuery($sql);
return $sql;
}
function storexecute($paramstring) // finalises write to db :
{
echo "\nExecuting with string : " . $paramstring . "\n";
$dbo = database::getInstance(); // Second getInstance needed ?
$dbo->execQuery(array($paramstring));
}
//table class also includes buildQuery function which returns $sql string - tested ok
=======
Controller :
$dbo = database::getInstance();
$movements = new trainmovts();
$stmt = $movements->storeprep(); // set up prepared query
After these initial steps, the Controller runs through a continuous loop, selects the fields needed for storage into a parameter array $exec, then calls $movements->storexecute($exec);
My immediate problem is that I get the error message "Catchable fatal error: Object of class database could not be converted to string " at the Database prepquery function (which is called by the Table storeprep fn)
Can anyone advise on this immediate prob, whether the subsequent repeated executes should work in this way, and more widely should I change anything with the structure ?
I think your problem in this line $dbo->stmt = $this->$dbo->prepare($sql);, php want to translate $dbo to string and call function with this name from this. Actually you need to use $this->dbo.
And actually your functions not static, so i think you don't need to call getInstance each time, you can use $this.