Efficient way to reuse the same call to the same sql table - php

So I search for this title hoping someone would have already answered it however, I came across similar topics on other languages but not PHP so maybe this will help others.
I am constantly using this following script to call on the database but how can I create it so that I can make it just once at the top of the class for example and use it in every method on the class page that needs it. Example: An single page may not have all of the data it needs from the same table but if the table contains 50% of the data or more for that page, how can I modify this so that I can just say it once and let the rest of the following scripts display the data it extracted in the first place by calling it all just once?
Here's what I have now.
<?php
if($res = $dbConn->query("SELECT Column FROM Table")){
while($d = $res->fetch_assoc()){
printf("Enter HTML here with proper %s", $d['Column']);
}
}
?>
I want to call on this without the printf(" "); collect and store the data so that I can then call the results while printing or echoing the results with the HTML in other methods. What os the most efficient way? I don't want to make the same call over and over and over... well, you get the point.
Should I use fetch_array or can I still do it with fetch_assoc?

not very sure if it's the answer you want.
you can use include/include_once/require/require_once at the top of the page you want to use the function
for example:
general_function.php:
-----
function generate_form( $dbConn, $sql ) {
if($res = $dbConn->query("SELECT Column FROM Table")) {
while($d = $res->fetch_assoc()) {
printf("Enter HTML here with proper %s", $d['Column']);
}
}
}
and for those pages you want to use the function, just put
include "$PATH/general_function.php";
and call generate_form

Try this:
class QueryStorage {
public static $dbConn = null;
public static $results = [];
public static function setConnection($dbConn) {
self::$dbConn = $dbConn;
}
public static function query($query, $cache = true) {
$result = (array_key_exists($query, self::$results))?
self::$results[$query] : self::$dbConn->query($query);
if($cache) {
self::$results[$query] = $result;
}
return $result;
}
public static function delete($query) {
unset(self::$results[$query]);
}
public function clean() {
self::$results = [];
}
}
usage:
at top somewhere pass connection to class:
QueryStorage::setConnection($dbConn);
query and store it:
$result = QueryStorage::query("SELECT Column FROM Table", true);
if($result){
while($d = $result->fetch_assoc()){
printf("Enter HTML here with proper %s", $d['Column']);
}
}
reuse it everywhere:
$result = QueryStorage::query("SELECT Column FROM Table", true); // it will return same result without querying db second time
Remember: it's runtime cache and will not store result for second script run. for this purposes You can modify current class to make it
work with memcache, redis, apc and etc.

If I understood you correctly, then the trick is to make an associative array and access with its 'key' down the code.
$dataArray = array();
// Add extra column in select query for maintaining uniqness. 'id' or it can be any unique value like username.
if($res = $dbConn->query("SELECT Column,id FROM Table")){
while($d = $res->fetch_assoc()){
$dataArray[$d['id']] = $d['Column'];
}
}
//you have value in the array use like this:
echo $dataArray['requireValueId'];
//or , use 'for-loop' if you want to echo all the values

You need a function which takes in the query as a parameter and returns the result.
Like this:
public function generate_query($sql) {
if($res = $dbConn->query($sql)){
while($d = $res->fetch_assoc()){
printf("Enter HTML here with proper %s", $d['Column']);
}
}
}

Related

the data do not display in my view

Undefined variable: data in my view
This is a simple display data in the input.
So, why this input isn't display my query result at it?
my view
<input type="text" name="sitename" value="<?php echo $data['sitename']; ?>"><br>
model
public function getData()
{
$query = "SELECT * FROM $this->tablename ORDER BY 'id' DESC LIMIT 1";
if (!$sqli = mysqli_query($this->cxn->connect(),$query))
{
throw new Exception("Error Processing Request");
}
else
{
$num = mysqli_num_rows($sqli);
while ($num > 0)
{
$data = mysqli_fetch_array($sqli);
$num--;
}
return $data;
}
}
Simply because a variable is declared somewhere, doesn't mean it is available everywhere. All variables have scope in which they are accessible. See this: http://php.net/manual/en/language.variables.scope.php for more information on scope.
You need to pass the $data variable into your view. I image you're using some sort of MVC framework since you have a model and a view. If this is the case you can lookup how to pass variables into views in that specific framework. The basic structure of your controller method might look something like this:
//sudo code - not specific to an actual framework
public function controller_method()
{
$data = $model->getData();
$this->template->set('data',$data);
$this->template->load('view');
}
Just search how to do that in your specific framework. Hope that helps!
EDIT
Base on your comment it looks like you're setting data after you load the view. You need to swap the order and call $display = new Display("main"); $data = $display->getData(); before you include'../model/display.php';
If the query returns 0 rows, your while() loop will never execute, so it won't set $data.
Since you're only returning 1 row from the query, you don't need a loop, you can just use an if. Then you can return $data only when it succeeds.
public function getData()
{
$query = "SELECT * FROM $this->tablename ORDER BY 'id' DESC LIMIT 1";
if (!$sqli = mysqli_query($this->cxn->connect(),$query))
{
throw new Exception("Error Processing Request");
}
else
{
if ($data = mysqli_fetch_array($sqli))
{
return $data;
}
else
{
return null;
}
}
}

How to pass variable value to another file via class'

I have my main (user visible) file which displays posts, and I need to set-up pagination.
It would be easy if I fetch DB in the same file (but I want to avoid that), that is why I created a seperate (user hidden) file which contains class' which are then called from main file(blog.php):
BLOG.php(simplified):
<?php
require 'core.php';
$posts_b = new Posts_b();
$posts_bx = $posts_b->fetchPosts_b();
foreach($posts_hx as $posts_hy){
echo $posts_hy['title'];
}
?>
core.php(simplified);
class Posts_b extends Core {
public function fetchPosts_b(){
$this->query ("SELECT posts_id, title FROM posts");
//return
return $this->rows();
}
}
This works like a charm, but now I need to do the count within query, which works fine, and which gives me a variable $pages=5 (handled inside class posts_b - in file core.php),
core.php(simplified-with variable);
class Posts_b extends Core {
public function fetchPosts_b(){
$this->query ("SELECT posts_id, title FROM posts");
$pages=5;
//return
return $this->rows();
}
}
Now I need a way to return this variable value to blog.php (the way I return rows())
Please help, anyone,
Thank you...
A function can only have a single return value.
There are ways to get around this though. You can make your return value be an array that contains all of the values you want. For example:
return array("pages"=>$pages, "rows"=>$this->rows());
Then in your code
require 'core.php';
$posts_b = new Posts_b();
$posts_bx = $posts_b->fetchPosts_b();
$pages = $posts_bx["pages"];
foreach($posts_hx["rows"] as $posts_hy){
echo $posts_hy['title'];
}
?>
Or you can adjust a input parameter provided it was supplied as a reference
public function fetchPosts_b(&$numRows){
$this->query ("SELECT posts_id, title FROM posts");
//return
return $this->rows();
}
In your code
require 'core.php';
$posts_b = new Posts_b();
$pages = 0;
$posts_bx = $posts_b->fetchPosts_b(&$pages);
foreach($posts_hx["rows"] as $posts_hy){
echo $posts_hy['title'];
}
?>
Or you can opt to figure out your pagination outside of the fetchPosts_b method.
$posts_bx = $posts_b->fetchPosts_b();
$pages = floor(count($posts_bx)/50);

php pdo in class + best method to display return array

I have the following class:
<?php
class photos_profile {
// Display UnApproved Profile Photos
public $unapprovedProfilePhotosArray = array();
public function displayUnapprovedProfilePhotos() {
$users = new database('users');
$sql='SELECT userid,profile_domainname,photo_name FROM login WHERE photo_verified=0 AND photo_name IS NOT NULL LIMIT 100;';
$pds=$users->pdo->prepare($sql); $pds->execute(array()); $rows=$pds->fetchAll();
$unapprovedProfilePhotosArray = $rows;
echo 'inside the class now....';
foreach($rows as $row) {
echo $row['userid'];
}
}
}
I can display the data successfully from the foreach loop.
This is a class that is called as follows and want to be able to use the array in the display/view code. This why I added the "$unapprovedProfilePhotosArray = $rows;" but it doesn't work.
$photos_profile = new photos_profile;
$photos_profile->displayUnapprovedProfilePhotos();
<?php
foreach($photos_profile->unapprovedProfilePhotosArray as $row) {
//print_r($photos_profile->unapprovedProfilePhotosArray);
echo $row['userid'];
}
?>
What is the best way for me to take the PHP PDO return array and use it in a view (return from class object). I could loop through all the values and populate a new array but this seems excessive.
Let me know if I should explain this better.
thx
I think you're missing the $this-> part. So basically you're creating a local variable inside the method named unapprovedProfilePhotosArray which disappears when the method finishes. If you want that array to stay in the property, then you should use $this->, which is the proper way to access that property.
...
$pds=$users->pdo->prepare($sql); $pds->execute(array()); $rows=$pds->fetchAll();
$this->unapprovedProfilePhotosArray = $rows;
...

Php Display While Loop From Function

I have a question regarding displaying the contents of a function, this function displaying a while loop.
Here is a function within my model:
function get_results($id)
{
$stmt = "select * where ... "
$stmt = $this->BEAR->Database->query($stmt);
$result = '';
while($row = mysqli_fetch_array($stmt))
{
$result .= '<div>';
$result .= $row['name'];
$result .= '</div>';
}
$this->BEAR->Template->setData('loop', $result, FALSE);
}
This is my Controller:
$BEAR->Webprofile->get_results(Template->getData('id'));
And this is my view:
<?php echo $this->getData('loop');?>
This displays the Loop within my view with no problem. But what I wish for is not to have any HTMl within my Model, Is there anyway of doing this (As this can cause a large amount of HTML in my Model). Maybe a way I can set the data within the Model and then get the data within my view.
I tried setting within the Model functions while loop individually like the following:
while($row = mysqli_fetch_array($stmt))
{
$this->BEAR->Template->setData('name', $row['name']);
$this->BEAR->Template->setData('name', $row['age']);
}
Then call the function in the Controller and call each setData, but this only displayed the first result not the full while loop of contents.
Therefore I wish to display all the contents of my while loop in my view (with HTML) but wish my function to just be getting and setting the Data. Can this be done? Any thoughts or guidance would be appreciated.
You need to apply some discipline to your MVC. Your models need to return raw data. It should return only objects or arrays of data. The key is consistency.
Your views need to include all the code to add your html formatting. Having a view that simply calls a model function you wrote that spits out a div or an ordered list, makes the entire concept of the view useless. Your views should provide all the HTML code.
Since you're using PHP, you can easily drop in and out of HTML.
Start with something like this in your model:
function get_results($id)
{
$stmt = "select * where ... "
$stmt = $this->BEAR->Database->query($stmt);
$results = array();
while($row = mysqli_fetch_array($stmt))
{
$results[] = $row['name'];
}
return results;
}
From there, you should be able to figure out that your controller should call this function, and pass the $results into your view/template along with the specific view file for rendering.
function get_results($id)
{
$stmt = "select * where ... "
$stmt = $this->BEAR->Database->query($stmt);
$result = '';
$result = mysqli_fetch_array($stmt);
return $result;
}
Then in your controller:
$this->BEAR->Template->setData('loop', $model->get_results($id), FALSE);
Then in your template
foreach($rows as $row){
....do something with each row
}
full example of how to get the data from the model and then pass to the template
class MyController {
function controller_showResults(){
$model = new Model();
$results = $model->get_results($_GET['id']);
$this->BEAR->Template->setData('loop', $results, FALSE);
}
}
Now the view assuming that the first argument to setData in template is a variable passed to the view and that variable is $results
<?php foreach($loop as $l): ?>
<div><?php echo $l['name'] ?></div>
<?php endforeach; ?>

PHP/MySQL isolating database access in a class - how to handle multiple row result set in an OOP manner

PHP/MySQLisolating database access in class - how to handle multiple row Selects
Here’s a coding question.
I isolated all DB access functions in a class
<?php
class DB {
var $conn;
function DBClass () {
#$this-> conn = mysqli_connect (DB_SERVER, DB_USER, DB_PASS, DB_NAME);
}
function validateUser ($aUserid, $aPassword) {
… validation code – sql injection code etc..
$sql = "Select userid, name, level From users where userid = '$aUserid' and password = '$aPassword'";
$result = mysqli_query ( $this->conn, $sql );
if (!$result || (mysqli_num_rows ($result) < 1)) {
return false;
}
$dbarray = mysqli_fetch_assoc ($result); // get a row
return $dbarray;
}
function getProduct ($aProductid) {
return $dbarray;
}
function getProductList () {
// <----------- this would be the problem function
}
}
$DB = new DBClass();
?>
My calling routine:
<?php
$dbarray = $DB->validateUser ($_POST['userid'], $_POST['password']);
?>
No problem it works fine. I run into a problem with a result set of more than one row. Now I have to get back to the class object for each row. It’s no problem if I include the MySQL code in the calling routine, but I’d like to keep it isolated in my class and I’m not sure how to code it.
Any thoughts? Any examples?
If you use PHP 5.3.0 and mysqlnd, you can use the new function mysqli_fetch_all(). This returns an array of associative arrays.
If you use an earlier version of PHP, you could switch to using PDO, and use the function PDOStatement::fetchAll().
You ask in a comment what about a very large result set. It's true that an unbounded result set could cause the array to exceed your PHP memory limit and that would cause a fatal error and halt the script. But is this really a problem? How many products do you have? You could use LIMIT to make sure the query isn't unbounded.
Re the other part of your questions regarding going back to a class, I'd suggest making an Iterator class:
class DB implements IteratorAggregate
{
protected $_data = array();
public function getProductList() {
// fetch all results from SQL query, stuff them into $this->_data
return $this->getIterator();
}
public function getIterator() {
return new ArrayIterator($this->_data);
}
}
Now you can use the class in a foreach loop:
$db = new DB();
foreach ($db->getProductList() as $product) {
// do something with each product
}
The IteratorAggregate interface means you can even do this:
$db = new DB();
$db->getProductList();
// ...other steps...
foreach ($db as $product) {
// do something with each product
}
Of course you could only store one result set at a time with this method. If you used your DB class for any other queries in the meantime, it would complicate things. For this reason, most people don't try to write a single class to encapsulate all database operations. They write individual classes for each type of Domain Model they need to work with, decoupled from the database connection.
you could save the result in an array and return it:
function getProductList () {
$sql = "SELECT ...";
$result = mysqli_query ( $this->conn, $sql );
$myProducts = array();
while ($row = mysqli_fetch_assoc($result))
$myProducts[] = $row; // or array_push($myProducts, $row)
}
return $myProducts
}
As a result you'll have an array of arrays and each element of it will contain one row of the result.
You have a SQL injection right in your login page.
What happens if someone inputs that as password:
xxx' OR 'yyy' <> 'x

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