Retrieving and Displaying Data From a Table

Question

At the moment, I have created a code that retrieves data from the database and displays it. However, for some reason, I cannot see the files I want to retrieve on my page. My goal is that the data gets retrieved from the database, and is displayed on the webpage. I do not need to make a connection with the database since Wordpress does that automatically.

My code:

<?php

global $wpdb;
// this adds the prefix which is set by the user upon instillation of wordpress
$table_name = $wpdb->prefix . "wpex_programma";
// this will get the data from your table
$retrieve_data = $wpdb->get_results( "SELECT * FROM wpex_programma; " );
print_r($retrieve_data);
?>
<ul>
<?php foreach ($retrieve_data as $retrieved_data){ ?>
<li><?php echo $retrieved_data->column_name;?></li>
<li><?php echo $retrieved_data->another_column_name;?></li>
<li><?php echo $retrieved_data->as_many_columns_as_you_have;?></li>
<?php 
}
?>
</ul>

My question: the data is not shown and I believe it is not retrieved. How can I fix that? The table name is correct, and I have data in my database tabel. The print_r($retrieve_data)returns the following: Array ( [0] => stdClass Object ( [id] => 35 [naam] => /public_html/wp/wp-content/plugins/AbonneerProgrammas/FilesUpload/Country Kickin 1.mp3 ) )

My query log:

My database structure:

New:

<?php

global $wpdb;
// this adds the prefix which is set by the user upon instillation of wordpress
$table_name = $wpdb->prefix . "wpex_programma";
// this will get the data from your table
$retrieve_data = $wpdb->get_results( "SELECT * FROM wpex_programma; " );
print_r($retrieve_data);
?>
<ul>
<?php foreach ($retrieve_data as $retrieved_data){ ?>
<li><?php echo $retrieved_data->id;?></li>
<li><?php echo $retrieved_data->naam;?></li>
<?php 
}
?>
</ul>

Answer 1

You have this:

<li><?php echo $retrieved_data->column_name;?></li>
<li><?php echo $retrieved_data->another_column_name;?></li>
<li><?php echo $retrieved_data->as_many_columns_as_you_have;?></li>

Here, the code tries to output the data in the column_name column, but there is no column in the table by that name.

Likewise, there is no another_column_name or as_many_columns_as_you_have columns in your table.

We know that the query pulls in the data, because when you used print_r we could see the data. We also know that when we did that we didn't see fields named column_name, we saw fields named id and naam.

After a little digging, it looks like you took a generic example from here:

https://wordpress.stackexchange.com/a/54641/736

But didn't make any modifications to match your table. The example wasn't a copy paste work anywhere code block, such a thing does not exist for what you want.

Your table has id and naam columns, these are what the code should be using, not another_column_name or as_many_columns_as_you_have