del_item.php File Reference

delete an item from the database More...

Go to the source code of this file.

Functions
	del_item ($smarty, $INPUT, $db)
	delete an item from the database
	do_delete_item ($item, $id, $db)
	delete an item from the database, without safety checks
	may_delete_item ($item, $id, $db)
	perform safety checks on whether it is possible to delete an item

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Detailed Description

delete an item from the database

Definition in file del_item.php.

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Function Documentation

del_item	(	$	smarty,
		$	INPUT,
		$	db
	)

delete an item from the database

This is a function to delete an item, called by action.php. Before performing the delete, it checks whether the item can be deleted without corrupting the database.

If the item cannot be deleted, the action is aborted and the user is informed about the error.

Parameters:

	$smarty	-- Smarty template engine handle
	$INPUT['item']	-- item type
	$INPUT['id']	-- id of the item to be deleted
	$db	-- MySQL database handle

Definition at line 29 of file del_item.php.

References $validation_info, check_input(), delete_file(), do_delete_item(), do_template(), and may_delete_item().

                                        {
global $_SESSION, $validation_info;


$default = array(
);

$INPUT = array_merge($default, $INPUT);
$errors = check_input($INPUT, $validation_info); 

if ($debug_level > 10) {
         print "<hr><pre>Input: ";
        print_r($INPUT);
        print "</pre><hr>";
}

if (!empty($errors)) {
        user_error("Missing or malformed input parameter(s): " . join($errors, ", "),
                E_USER_ERROR); 
}


if (!empty($INPUT['file'])) {


        # just delete an attached file
        delete_file($INPUT['item'], $INPUT['id'], $INPUT['file']);


} else {

        if (!may_delete_item($INPUT['item'], $INPUT['id'], $db)) {
                do_template($smarty, 'no_delete.tpl' , $INPUT, FALSE);
                exit(0);
        }

        # delete the whole item
        do_delete_item($INPUT['item'], $INPUT['id'], $db);

}

}

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do_delete_item	(	$	item,
		$	id,
		$	db
	)

delete an item from the database, without safety checks

Actually performs the deletion, without checking whether it would corrupt the database.

Parameters:

	$smarty	-- Smarty template engine handle
	$INPUT['item']	-- item type
	$INPUT['id']	-- id of the item to be deleted
	$db	-- MySQL database handle

Definition at line 82 of file del_item.php.

References delete_file(), list_files(), and sql_query().

Referenced by del_item().

                                         {

        $sql_table = array (
                "article"    => "document",
                "book"       => "document",
                "file"        => "document",
                "url"        => "document",
                "collection" => "collection",
                "user"       => "user",
                "email"      => "email",
        );

        switch($item) {

        case "user":

                $p = array (
                        "tables"  => "collection",
                        "cond"    => "collection.user_id = $id",
                        "columns" => "id"
                );

                $ans = sql_query('select', $p, $db);

                foreach ($ans as $a) {
                        do_delete_item("collection",$a['id'], $db);
                }

                break;

        case "collection":

                $p = array (
                        "tables"  => "document, doc_type",
                        "cond"    => "document.collection_id = $id AND doc_type.id = document.doc_type_id",
                        "columns" => "document.id AS id, doc_type.name AS type"
                );

                $ans = sql_query('select', $p, $db);

                foreach ($ans as $a) {
                        do_delete_item($a['type'], $a['id'], $db);
                }

                break;

        case "email":
                break;

        default: // document

                $p = array (
                        "tables"  => "email",
                        "cond"    => "email.document_id = $id",
                        "columns" => "id"
                );

                $ans = sql_query('select', $p, $db);

                foreach ($ans as $a) {
                        do_delete_item("email",$a['id'], $db);
                }

                break;

        }


        $t = $sql_table[$item];

        $p = array (
                "table"  => $t,
                "cond"    => "id = $id",
        );

        sql_query('delete', $p, $db);

        # delete all attached documents

        $files = list_files($item, $id);

        foreach ($files as $f => $f_info) {
                delete_file($item, $id, $f);
        }

}

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may_delete_item	(	$	item,
		$	id,
		$	db
	)

perform safety checks on whether it is possible to delete an item

Certain objects cannot be deleted without risking an inconsitent database. For example, a user cannot be deleted as long as there are any active collections that he owns. Likewise, a collection cannot be deleted as long as there are pending book orders for this collection. This function checks for these conditions.

Parameters:

	$item	-- item type
	$id	-- id of the item to be deleted
	$db	-- MySQL database handle

Returns:

true if the item can be deleted

Definition at line 183 of file del_item.php.

References sql_query().

Referenced by del_item().

                                          {

        $sql_table = array (
                "article"    => "document",
                "book"       => "document",
                "file"        => "document",
                "url"        => "document",
                "collection" => "collection",
                "user"       => "user",
                "email"      => "email",
        );

        $t = $sql_table[$item];

        $p = array (
                "tables"  => "state,$t",
                "cond"    => "state.id = $t.state_id AND $t.id = $id", 
                "columns" => "state.name AS state_name",
                "order" => "$t.id"
        );

        $ans = sql_query('select', $p, $db);
        
        if (empty($ans)) {
                user_error("No such item: $item, id=$id", E_USER_ERROR); 
        } 

        switch($item) {

        case "user":

                $ok = TRUE;

                $p = array (
                        "tables"  => "collection",
                        "cond"    => "collection.user_id = $id",
                        "columns" => "id"
                );

                $ans = sql_query('select', $p, $db);

                foreach ($ans as $a) {
                        $ok = $ok && may_delete_item("collection",$a['id'], $db);
                }

                break;

        case "collection":

                $ok = TRUE;

                $p = array (
                        "tables"  => "document, doc_type",
                        "cond"    => "document.collection_id = $id AND doc_type.id = document.doc_type_id",
                        "columns" => "document.id AS id, doc_type.name AS type"
                );

                $ans = sql_query('select', $p, $db);

                foreach ($ans as $a) {
                        $ok = $ok && may_delete_item($a['type'], $a['id'], $db);
                }

                break;

        case "email":
        case "file":
        case "url":
                $ok = TRUE;
                break;

        default:
                $ok =   ($ans[0]['state_name'] == "inactive") or
                        ($ans[0]['state_name'] == "new");
                break;
        }

        return $ok;
}

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