6.3. Data removal protection

One very old database maintenance rule basically says:

 

No entry should by removed from a database, but just marked as deleted.

 
-- unknown author  

According to this rule, we may want to implement similar functionality also in phpMyEdit and it is possible, of course.

First of all we need to set-up phpMyEdit to list only valid non-deleted records. This can be accomplished using $opts['filters'] configuration option. We suppose that we have table where a column named deleted indicates if record is deleted or not.

Example 6-3. Non-deleted records listing

$opts['filters'] = 'deleted IS NULL OR deleted = 0';

Than we have to create a "delete before" trigger and we are done. Trigger PHP code should look similar to this example:

Example 6-4. Trigger for marking records as deleted

 $query2 = sprintf('UPDATE %s SET deleted = 1 WHERE id = %d', $this->tb, $newvals['id']); $this->MyQuery($query2); return false;

To recover a particular record just change the value in the deleted column from  1 to  0 using your SQL client or interface (for example using phpMyAdmin).


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