Deleteing related files?

Suppose I have two tables ...

Table one

dog_id
dog_name

Table two

picture_id
picture_dog_id
Picture_file

Table one is a table of dogs and their names. Table two is a table of extra photos for each dog using the dog_id and picture_dog_id as the relationship between the two.

Is it possible on deletion of a dog from table one to delete the related images or even prevent deletion of the dog if there is matching images?

Deleting the corresponding entries from the second table when you delete a dog from the first is definitely possible. You would just have an additional delete record server behavior and specify to delete from your second table where the deleted dog id matches the picture_dog_id. You can also use the delete files server behavior to delete the corresponding images as well.

To prevent the dog record from being deleted if there are entries in the other table you would have to do a custom check by having a recordset that selects all from the second table where the id matches for the first table. If there are any records in this recordset it would indicate that there are corresponding records. You could then redirect and display an error message.

Please post back with any specific questions that you have about any part of this.

Thanks Eric,

Good to know its possible ....

But how would I go about deleting however many related records there is? Sometimes there might be one record, sometimes none, sometimes maybe fifty?

This would be a very good and handy tutorial in your documentation.

Brad

This is one of the nice things about using a delete server behavior for the records. If you filter the delete where the id matches the id of the record you are removing then it does not matter if you have one or a thousand records that have that id as the foreign key, they will all be deleted since they match the criteria.

Originally Said By: Eric Mittman

  This is one of the nice things about using a delete server behavior for the records. If you filter the delete where the id matches the id of the record you are removing then it does not matter if you have one or a thousand records that have that id as the foreign key, they will all be deleted since they match the criteria.  

Thanks Matt,

So you don't have to have any sort of repeat? I'll give it a try this afternoon.

Brad

That is exactly rite, when deleting records from a table if you base the delete on a particular column matching a value wherever the column matches that value the record will be deleted.

I'm currently doing the same thing and it works great. My question is, how would you go about deleting the image files associated with the photo table?

I added a delete behavior with Digital Assist Pro to do this and it works great. But it will only delete 1 image from the folder. How would I go about delete multiple files with that behavior?

I tried this, but it still would only delete 1 image from the folder.

<?php

do {
$WA_DeleteFileResult1 = false;
if(isset($_POST["DeleteGallery_x"])){


$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("../../pawpics_gallery/".$_SESSION['pawsid'] ."/", "".$row_photosRS['PhotoFilename'] ."");
}

} while ($row_photosRS = mysql_fetch_assoc($photosRS));
?>


Thanks

It looks like you have the rite idea, looping over the delete for each file you would like to remove seems like the correct approach. Have you checked on your recordset after the page submits to check and see if you have all of the files contained within it? You should be able to add in some debug code to determine how many times the loop is iterating, this should give you a clue about why you are only seeing the one file delete.

I'm doing the same loop on the page and outputting the recordset. e.g. image1.jpg image2.jpg, image3.jpg - so it looks like it's fine.

It will only delete one, it's like the loop isn't looping.

I pull the post statement out like below, still didn't work.

<?php
if(isset($_POST["DeleteGallery_x"])){
do {
$WA_DeleteFileResult1 = false;
$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("../../pawpics_gallery/".$_SESSION['pawsid'] ."/", "".$row_photosRS['PhotoFilename'] ."");
} while ($row_photosRS = mysql_fetch_assoc($photosRS));
}?>

You should try setting a variable outside of the loop, then accumulate this value within the loop so that you can determine how many times the loop is occurring. You could set it up like so:

$the_deleted_filenames = "";

do { 

$the_deleted_filenames .= $row_photosRS['PhotoFilename'] . ", ";

$WA_DeleteFileResult1 = false;

$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("../../pawpics_gallery/".$_SESSION['pawsid'] ."/", "".$row_photosRS['PhotoFilename'] ."");

} while ($row_photosRS = mysql_fetch_assoc($photosRS)); 

die("the deleted file names are: " . $the_deleted_filenames);

Give this a try to see the names of the files that are attempted to be deleted.