Running an ODBC_FETCH_ARRAY in a WHILE Loop is Not Echoing Results

As a web developer, it’s frustrating when your code works on most pages but not on one specific page. This post will delve into the issues with running an ODBC FETCH_ARRAY query in a WHILE loop and provide solutions to echo results.

Introduction

ODBC (Open Database Connectivity) is a standard for accessing database servers from applications written in different programming languages. PHP’s ODBC extension allows developers to connect to various databases, including Microsoft Access and other ODBC-compliant databases. This post will focus on resolving issues with running an ODBC FETCH_ARRAY query in a WHILE loop.

The Issue

The problem lies in the way the FETCH_ARRAY function is being used within the WHILE loop. When using FETCH_ARRAY, the result set returned by the query is stored in a variable, which can be iterated through using an array syntax (e.g., $row = odbc_fetch_array($result)). However, when trying to echo or output individual values from this array within the same scope as the loop, issues arise.

In the provided code snippet, we’re executing an ODBC query that fetches data into a result set. We then use a WHILE loop to iterate through each row of the result set using odbc_fetch_array. The problem is with outputting individual values within this scope.

Problematic Code

The problematic line of code in question is:

while($row=@odbc_fetch_array($resultPTLstats)){
    echo '<tr><td>'.$row['DATE_STAMP'].'</td>
       <td>'.$row['PA'].'</td>
       <td>'.$row['HOURS'].'</td>
       <td>'.$row['NT'].'</td>
       <td>'.$row['TP'].'</td>
       <td>'.$row['TL'].'</td>
       <td>'.$row['LPH'].'</td>
       <td>'.$row['PPH'].'</td>
      </tr>';
}

This code attempts to echo individual values ($row['DATE_STAMP'], $row['PA'], etc.) within the WHILE loop. The problem is that these variables are not being echoed directly; instead, they’re being echoed as part of a larger string ('<tr><td>').

Solution

To resolve this issue, we need to restructure our code so that it doesn’t try to echo individual values within the loop. One solution is to create an HTML table with separate <th> elements for each column and then iterate through the rows in a more traditional manner.

Here’s a revised version of the problematic code:

<table class="table table-sm table-bordered text-center table-stripped">
    <thead>
        <tr>
            <th>Date Stamp</th>
            <th>PA</th>
            <th>HOURS</th>
            <th>NT</th>
            <th>TP</th>
            <th>TL</th>
            <th>LPH</th>
            <th>PPH</th>
        </tr>
    </thead>
    <tbody>
        <?php
        while($row = odbc_fetch_array($resultPTLstats)){
            echo '<tr>';
            echo '<td>'.$row['DATE_STAMP'].'</td>';
            echo '<td>'.$row['PA'].'</td>';
            echo '<td>'.$row['HOURS'].'</td>';
            echo '<td>'.$row['NT'].'</td>';
            echo '<td>'.$row['TP'].'</td>';
            echo '<td>'.$row['TL'].'</td>';
            echo '<td>'.$row['LPH'].'</td>';
            echo '<td>'.$row['PPH'].'</td>';
            echo '</tr>';
        }
        ?>
    </tbody>
</table>

Additional Solutions

Another solution to this problem is to use a more traditional loop structure, such as for loops. These can be used in combination with the odbc_fetch_array function to iterate through each row of the result set.

$resultRow = array();
while($resultRow = odbc_fetch_array($resultPTLstats)){
    echo 'Date Stamp: '.$resultRow['DATE_STAMP'].'<br>
           PA: '.$resultRow['PA'].'<br>
           HOURS: '.$resultRow['HOURS'].'<br>
           NT: '.$resultRow['NT'].'<br>
           TP: '.$resultRow['TP'].'<br>
           TL: '.$resultRow['TL'].'<br>
           LPH: '.$resultRow['LPH'].'<br>
           PPH: '.$resultRow['PPH'].';
}

Conclusion

When using FETCH_ARRAY within a WHILE loop, outputting individual values can be problematic. By restructuring your code to use separate elements or traditional loops, you can avoid these issues and easily echo results from your database query.

Last modified on 2023-08-25