Updating and deleting data in D7 - drupal-7

Question

I have made a form in D7 using form API, registered some users and retrieved their registered data from database;now what i want is to add an edit and a delete link in front of every row in the retrieved table;i have done that in PHP but how to implement same in Drupal?;anybody having any idea how to do that?
My retrieval code is:
function form_data_menu() {
$items['formdata'] = array(
'title' => 'Form Data',
'page callback' => 'form_data_form',
'access callback' => TRUE,
);
return $items;
}
function form_data_form()
{
$results = db_query('SELECT * FROM {drupal}');
$header = array(t('Id'),t('Name'),t('College'),t('Education'),t('Percentage'),t('Application'));
$rows = array();
foreach($results as $result) {
$rows[] = array(
$result->id,
$result->name,
$result->college,
$result->education,
$result->percentage,
$result->application,
);
}
return theme('table',array('header'=>$header,'rows'=>$rows));
}
I can add links though but the main problem is how to run update and delete queries in D7?
Any help will be appreciated. Thank you!

Answer 1

Start with the example module "dbtng_example.module".
https://www.drupal.org/project/examples
This will give an example of how to set up a module to save to the database. I used this recently to create a custom module to save data to a new database table within drupal. To figure out how to set up the hook_schema, you can look at ".install" files within the drupal core and contributed codebase.
Then to create an edit or delete link, you need to alter your hook_menu to pass in the unique id for that element:
$items['admin/structure/nates-custom-page/update/%'] = array(
'title' => 'Update entry',
'page callback' => 'drupal_get_form',
'page arguments' => array('nates_module_form_update', 5),
'weight' => -5,
'access arguments' => array('administer DFP'),
);
$items['admin/structure/nates-custom-page/delete/%'] = array(
'title' => 'Delete entry',
'page callback' => 'drupal_get_form',
'page arguments' => array('nates_module_form_delete', 5),
'access arguments' => array('administer DFP'),
);
Above is an example where I added the argument (indicated by the percentage sign in the array key, ("%"), that will represent the unique id for that item I want to edit or delete.
Then alter the edit form to load the item you want to edit by the id.
And add a delete form.
Here's an example of a delete form:
function nates_module_form_delete($form, &$form_state) {
$entry = nates_module_entry_load_by_pid(arg(5));
$form = array();
$form['pid'] = array(
'#type' => 'value',
'#value' => arg(5),
);
$output = "";
foreach($entry as $key => $value) {
$output .= "<p><strong>$key</strong>: $value</p>";
}
$form['markup'] = array(
'#type' => 'markup',
'#markup' => $output,
);
return confirm_form(
$form,
t('Are you sure you want to delete this item? '),
'example/list',
t('This action cannot be undone.'),
t('Delete'),
t('Cancel')
);
return $form;
}
Notice I return a confirmation form first.
And here's the submit handler function that processes it after they submit the request:
function nates_module_form_delete_submit($form, &$form_state) {
global $user;
nates_module_entry_delete($form_state['values']['pid']);
drupal_set_message(t("Deleted entry"));
}
Then, edit your listing page to add the edit links and delete links:
function nates_module_list() {
$output = '';
// Get all entries in the dfp_amobee2 table.
if ($entries = nates_module_entry_load_all()) {
$rows = array();
foreach ($entries as $entry) {
// Sanitize the data before handing it off to the theme layer.
$entry->editlink = l('edit','admin/structure/nates-custom-page/update/' . $entry->pid, array('query' => array('destination' => 'admin/structure/nates-custom-page')));
$entry->deletelink = l('delete','admin/structure/nates-custom-page/delete/' . $entry->pid, array('query' => array('destination' => 'admin/structure/nates-custom-page')));
unset($entry->pid);
if(!empty($entry->tid)) {
$entry->alias = l($entry->alias, 'taxonomy/term/'.$entry->tid);
}
else if(isset($entry->pages)) {
if(drupal_valid_path($entry->pages)) {
$entry->alias = l(drupal_lookup_path('alias', $entry->pages),$entry->pages);
} else {
$entry->alias = check_markup($entry->pages);
}
} else {
$entry->alias = "";
}
unset($entry->pages);
if(!$entry->tid) {
$entry->tid = "";
}
$rows[] = (array) $entry;
}
// Make a table for them.
$header = array(t('path'), t('tid'), t('dfp tag machine_name'),t('amobee_as'), '', '');
$output .= '<p>' . t('If the "tid" is filled in, amobee_as will be used on taxonomy pages and on node pages (where the main term id matches). If the path is filled it, will be used on that path. Path supercedes "tid" when there is a conflict.') . '</p>';
$output .= theme('table', array('header' => $header, 'rows' => $rows));
}
else {
drupal_set_message(t('No entries have been added yet.'));
}
return $output;
}