Neither IF Nor ELSE Triggers In php Script Flow! Why? - php

Question

Folks,
I am not killing the script flow, before the CONDITION, with
die();
And so, one of the 2 should trigger:
IF
ELSE
But they don't.
if(!$result_2)
{
echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'IF' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'ELSE'. WHY ?
die("Fetching Error");
}
while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
{
echo __LINE__; echo "<br>";//LINE 98: THIS LINE IS LIKE AN 'ELSE'. IT DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
Either Line 92 (IF) should trigger or Line 98 (which is like the ELSE).
Do notice the comments in the code to understand where the script is ending the flow without any reason.
<?php
$query_2 = "SELECT id,page_url,link_anchor_text,page_description,keyphrases,keywords FROM links WHERE keywords = ? ORDER by id LIMIT $offset,$limit";
$stmt_2 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_2,$query_2))
{
echo __LINE__; echo "<br>";//LINE 84: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. LAST LINE THAT GETS ECHOED.
mysqli_stmt_bind_param($stmt_2,'s',$keywords);
mysqli_stmt_execute($stmt_2);
$result_2 = mysqli_stmt_get_result($stmt_2);
if(!$result_2)
{
echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'ELSE' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
die("Fetching Error");
}
What is killing the script flow ?
Context:
<?php
echo __LINE__; echo "<br>"; //LINE 16: THIS LINE GETS TRIGGERED AND ECHOED IN TEST
if(!ISSET($_GET['keywords']))
{
echo __LINE__; echo "<br>";
die("Type your keywords");
}
$keyword = $_GET['keywords'];
//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not, return the default: 1.
$page = ISSET($_GET['page']) && is_numeric($_GET['page']) ? $_GET['page'] : 1;
//Check if the PAGE RESULT LIMIT is specified or not and if it's a numer or not. If not, return the default: 1.
$limit = ISSET($_GET['limit']) && is_numeric($_GET['limit']) ? $_GET['limit'] : 1;
$query_1 = "SELECT COUNT(id) FROM links WHERE keywords = ?";
$stmt_1 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_1,$query_1))
{
echo __LINE__; echo "<br>";//LINE 57: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. BUT WHY SCRIPT FLOW DOES NOT GO BEYOND THIS LINE ?
mysqli_stmt_bind_param($stmt_1,'s',$keywords);
mysqli_stmt_execute($stmt_1);
$result_1 = mysqli_stmt_bind_result($stmt_1,$row_count);
mysqli_stmt_fetch($stmt_1);
}
else
{
echo __LINE__; echo "<br>"; //LINE 67
printf("Error: %s.\n", mysqli_stmt_error($stmt_1));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_1));
die("A. Prepare failed!");
}
mysqli_stmt_close($stmt_1);
//$total_pages = ceil($result_1/$limit); //SHOULD I KEEP THIS LINE OR THE ONE BELOW THIS ONE ?
$total_pages = ceil($row_count/$limit); //SHOULD I KEEP THIS LINE OR THE ONE ABOVE THIS ONE ?
$offset = (($page * $limit) - $limit);
$query_2 = "SELECT id,page_url,link_anchor_text,page_description,keyphrases,keywords FROM links WHERE keywords = ? ORDER by id LIMIT $offset,$limit";
$stmt_2 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_2,$query_2))
{
echo __LINE__; echo "<br>";//LINE 84: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. LAST LINE THAT GETS ECHOED.
mysqli_stmt_bind_param($stmt_2,'s',$keywords);
mysqli_stmt_execute($stmt_2);
$result_2 = mysqli_stmt_get_result($stmt_2);
if(!$result_2)
{
echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'IF' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'ELSE'. WHY ?
die("Fetching Error");
}
while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
{
echo __LINE__; echo "<br>";//LINE 98: THIS LINE IS LIKE AN 'ELSE'. IT DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
echo "LIMIT: $limit<br>";
echo "ROW COUNT: $row_count<br><br>";
echo "TOTAL PAGES: $total_pages<br><br>";
//Retrieve Values.
$id = $row["id"];
$page_url = $row["page_url"];
$link_anchor_text = $row["link_anchor_text"];
$page_description = $row["page_description"];
$keyphrases= $row["keyphrases"];
$keywords = $row["keywords"];
echo "Id: $id<br>";
echo "Page Url: $page_url<br>";
echo "Link Anchor Text: $link_anchor_text<br>";
echo "Page Description: $page_description<br>";
echo "Keyphrases: $keyphrases<br>";
echo "Keywords: $keywords<br>";
echo "<br>";
echo "<br>";
}
}
else
{
echo __LINE__; echo "<br>";//Line 124
printf("Error: %s.\n", mysqli_stmt_error($stmt_2));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_2));
die("B. Prepare failed!");
}
Also, out of these 2, which one is correct ?
$total_pages = ceil($result_1/$limit); //SHOULD I KEEP THIS LINE OR THE ONE BELOW THIS ONE ?
$total_pages = ceil($row_count/$limit); //SHOULD I KEEP THIS LINE OR THE ONE ABOVE THIS ONE ?
UPDATE
My code now looks like this.
My issues are mentioned clearly in the code comments in CAPITALS.
CURRENT ISSUES:
ISSUE 1:
Pagination Section only displays link to PAGE 1 from PAGE 1. Fails to display link to PAGE 2. Code configured to display 1 row per page. Since there are 2 matching rows then naturally 2 pages should display all the results. Why pagination section fails to display link to PAGE 2 from PAGE 1 ?
error_reporting.php
<?php
ini_set('display_errors','1');
ini_set('display_startup_errors','1');
ini_set('error_reporting',E_ALL);
?>
<?php
require 'conn.php';
require 'error_reporting.php';
?>
<!DOCTYPE HTML">
<html>
<head>
<meta name="viewport" content="width-device=width, initial-scale=1">
</head>
<body>
<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">
<label for="keywords">Keywords:*</label>
<input type="text" name="keywords" id="keywords" placeholder="Input Keywords" required>
<br>
<label for="limit">Results per Page</label>
<select name="limit" id="limit">
<option value="1">1</option>
<option value="10">10</option>
<option value="25">25</option>
<option value="50">50</option>
<option value="100">100</option>
</select>
<br>
<button name="search" id="search" value=" ">Search</button><br>
<button type="submit" name="search" id="search" value="search">Search</button>
<br>
<input type="reset">
<br>
</form>
<?php
echo __LINE__; echo "<br>"; //LINE 16: THIS LINE GETS TRIGGERED AND ECHOED IN TEST
if(!ISSET($_GET['keywords']))
{
echo __LINE__; echo "<br>";
die("Type your keywords");
}
$keywords = $_GET['keywords'];
//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not, return the default: 1.
$page = ISSET($_GET['page']) && is_numeric($_GET['page']) ? $_GET['page'] : 1;
//Check if the PAGE RESULT LIMIT is specified or not and if it's a numer or not. If not, return the default: 1.
$limit = ISSET($_GET['limit']) && is_numeric($_GET['limit']) ? $_GET['limit'] : 1;
$query_1 = "SELECT COUNT(id) FROM links WHERE keywords = ?";
$stmt_1 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_1,$query_1))
{
echo __LINE__; echo "<br>";//LINE 57: THIS LINE GETS TRIGGERED AND ECHOED IN TEST.
mysqli_stmt_bind_param($stmt_1,'s',$keywords);
mysqli_stmt_execute($stmt_1);
$result_1 = mysqli_stmt_bind_result($stmt_1,$row_count);
mysqli_stmt_fetch($stmt_1);
echo "ROW COUNT: $row_count<br><br>";
}
else
{
echo __LINE__; echo "<br>"; //LINE 67
printf("Error: %s.\n", mysqli_stmt_error($stmt_1));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_1));
die("A. Prepare failed!");
}
mysqli_stmt_close($stmt_1);
$total_pages = ceil($row_count/$limit);
$offset = (($page * $limit) - $limit);
$query_2 = "SELECT id,page_url,link_anchor_text,page_description,keyphrases,keywords FROM links WHERE keywords = ? ORDER by id LIMIT $offset,$limit";
$stmt_2 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_2,$query_2)) //LINE 82:
{
echo __LINE__; echo "<br>";//LINE 84: THIS LINE GETS TRIGGERED AND SO PREPARED STATEMENT DID NOT FAIL AT LINE 82!
mysqli_stmt_bind_param($stmt_2,'s',$keywords);
mysqli_stmt_execute($stmt_2);
$result_2 = mysqli_stmt_get_result($stmt_2);
if(!$result_2)
{
echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'IF' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'ELSE'. WHY ?
die("Fetching Error");
}
while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))//LINE 96: THIS LINE IS LIKE AN 'ELSE'. IT DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
{
echo __LINE__; echo "<br>";
echo "LIMIT: $limit<br>";
echo "ROW COUNT: $row_count<br><br>";
echo "TOTAL PAGES: $total_pages<br><br>";
//Retrieve Values.
$id = $row["id"];
$page_url = $row["page_url"];
$link_anchor_text = $row["link_anchor_text"];
$page_description = $row["page_description"];
$keyphrases = $row["keyphrases"];
$keywords = $row["keywords"];
echo "Id: $id<br>";
echo "Page Url: $page_url<br>";
echo "Link Anchor Text: $link_anchor_text<br>";
echo "Page Description: $page_description<br>";
echo "Keyphrases: $keyphrases<br>";
echo "Keywords: $keywords<br>";
echo "<br>";
echo "<br>";
}
}
else
{
echo __LINE__; echo "<br>";//LINE 124
printf("Error: %s.\n", mysqli_stmt_error($stmt_2));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_2));
die("B. Prepare failed!");
}
mysqli_stmt_close($stmt_2);
//PAGINATION SECTION STARTS FROM HERE:
//WHY PAGINATION SECTION FAILS TO DISPLAY ? ONLY A LINK TO PAGE 1 IS SHOWN WHEN YOU LOAD PAGE 1. NO LINK TO PAGE 2. THERE ARE 2 MATCHING ROWS. SCRIPT FIXED TO SHOW 1 ROW PER PAGE. AND SO, 2 PAGES SHOULD DISPLAY ALL RESULTS. HENCE, PAGINATION SECTION SHOULD SHOW A LINK TO PAGE 2 FROM PAGE 1. BUT PAGE 1 ONLY LINKS TO ITSELF IN THE PAGINATION SECTION.
if($page>$total_pages) //If Page Number is greater than Total Pages, show only a link to FINAL PAGE.
{
echo "?>";?><?php echo "<b> Final Page </b>";?><?php
}
else
{
$i = 1;
while($i<=$total_pages)
{
if($i<$total_pages)
{
echo "";?><?php echo " $i ";?><?php
}
elseif($i==$page) //Bold the Current Page Number.
{
echo "";?><?php echo "<b> $i </b>";?><?php
}
$i++;
}
}
?>
UPDATE AGAIN:
ISSUE: Missing in Url "&page=".
Look at this html:
<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">
As you can see, after clicking the form button, you should be sent to:
pagination_test_2.php?keywords=$keywords&limit=$limit&page=1"
But guess what ? you are sent to:
?keywords=$keywords&limit=$limit&search=search"
Where is the "&page=1" part in the url ?
Also, how not to have "search=search" added to the url ?
<?php
require 'conn.php';
require 'error_reporting.php';
?>
<!DOCTYPE HTML">
<html>
<head>
<meta name="viewport" content="width-device=width, initial-scale=1">
</head>
<body>
<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">
<label for="keywords">Keywords:*</label>
<input type="text" name="keywords" id="keywords" placeholder="Input Keywords" required>
<br>
<label for="limit">Results per Page</label>
<select name="limit" id="limit">
<option value="1">1</option>
<option value="10">10</option>
<option value="25">25</option>
<option value="50">50</option>
<option value="100">100</option>
</select>
<br>
<button name="search" id="search" value=" ">Search</button><br>
<button type="submit" name="search" id="search" value="search">Search</button>
<br>
<input type="reset">
<br>
</form>
<?php
echo __LINE__; echo "<br>";
if(!ISSET($_GET['keywords']))
{
echo __LINE__; echo "<br>";
die("Type your keywords");
}
$keywords = $_GET['keywords'];
//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not, return the default: 1.
$page = ISSET($_GET['page']) && is_numeric($_GET['page']) ? $_GET['page'] : 1;
//Check if the PAGE RESULT LIMIT is specified or not and if it's a numer or not. If not, return the default: 1.
$limit = ISSET($_GET['limit']) && is_numeric($_GET['limit']) ? $_GET['limit'] : 1;
$query_1 = "SELECT COUNT(id) FROM links WHERE keywords = ?";
$stmt_1 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_1,$query_1))
{
echo __LINE__; echo "<br>";
mysqli_stmt_bind_param($stmt_1,'s',$keywords);
mysqli_stmt_execute($stmt_1);
$result_1 = mysqli_stmt_bind_result($stmt_1,$row_count);
mysqli_stmt_fetch($stmt_1);
echo "ROW COUNT: $row_count<br><br>";
}
else
{
echo __LINE__; echo "<br>";
printf("Error: %s.\n", mysqli_stmt_error($stmt_1));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_1));
die("A. Prepare failed!");
}
mysqli_stmt_close($stmt_1);
$total_pages = ceil($row_count/$limit);
$offset = (($page * $limit) - $limit);
$query_2 = "SELECT id,page_url,link_anchor_text,page_description,keyphrases,keywords FROM links WHERE keywords = ? ORDER by id LIMIT $offset,$limit";
$stmt_2 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_2,$query_2))
{
echo __LINE__; echo "<br>";
mysqli_stmt_bind_param($stmt_2,'s',$keywords);
mysqli_stmt_execute($stmt_2);
$result_2 = mysqli_stmt_get_result($stmt_2);
if(!$result_2)
{
echo __LINE__; echo "<br>";
die("Fetching Error");
}
while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
{
echo __LINE__; echo "<br>";
echo "LIMIT: $limit<br>";
echo "ROW COUNT: $row_count<br><br>";
echo "TOTAL PAGES: $total_pages<br><br>";
//Retrieve Values.
$id = $row["id"];
$page_url = $row["page_url"];
$link_anchor_text = $row["link_anchor_text"];
$page_description = $row["page_description"];
$keyphrases = $row["keyphrases"];
$keywords = $row["keywords"];
echo "Id: $id<br>";
echo "Page Url: $page_url<br>";
echo "Link Anchor Text: $link_anchor_text<br>";
echo "Page Description: $page_description<br>";
echo "Keyphrases: $keyphrases<br>";
echo "Keywords: $keywords<br>";
echo "<br>";
echo "<br>";
}
}
else
{
echo __LINE__; echo "<br>";
printf("Error: %s.\n", mysqli_stmt_error($stmt_2));
printf("Error: %d.\n", mysqli_stmt_errno($stmt_2));
die("B. Prepare failed!");
}
mysqli_stmt_close($stmt_2);
if($page>$total_pages) //If Page Number is greater than Total Pages, show only a link to FINAL PAGE.
{
echo ""; echo "<b> Final Page </b>";?><?php
}
else
{
$i = 1;
while($i<=$total_pages)
{
if($i<$total_pages && $i!=$page)
{
echo ""; echo " $i ";?><?php
}
elseif($i==$page) //Bold the Current Page Number.
{
echo ""; echo "<b> $i </b>";?><?php
}
else
{
echo ""; echo " $i ";?><?php
}
$i++;
}
}
?>
Typos were on the urls in the pagination section. Now, I fixed them and so pagination section working fine.
Can someone be kind enough to checkout my code and let me know which lines to weedout if they are not really necessary.

Answer 1

I think neither lines are reached because the statement is valid but returns zero rows. Before $query_2 = ... could you add a check on $row_count to see if there are any rows?
To answer your second question, $total_pages = ceil($row_count/$limit); is the correct one to use because mysqli_stmt_bind_result returns a boolean so $result_1 would be true or false.
Personally I prefer object oriented style rather than procedural style as you have used because I find it easier to read but the choice is yours.