Fields being set to NULL on SQLFORM.grid update

[Jim S]

It is possible that I'm losing my mind, but it appears to me that when I submit a SQLFORM.grid update with a custom form that fields not included in the custom form are being set to NULL even if they had a value in them before.

I've just noticed this after updating to 2.5.1 stable.

-Jim

[Massimo Di Pierro]

Can we see an example?

[Jim S]

Here you go.  Attached.

-Jim

[Jim S]

I just reverted back to 2.4.6-stable+timestamp.2013.05.10.08.32.00 and the problem exists there as well.

-Jim

[Massimo Di Pierro]

The problem is that the grid expects the field to be writable in the form. You do not include them therefore it thinks they are empty (html convention, not web2py's).

Assuming you want the fields in the "create" form but not in the edit form you can replace:

    grid = SQLFORM.grid(db.person.id>0,

                        fields=[db.person.first, db.person.last])

with

    if request.args(0) == 'edit':

        db.person.song.writable = False

        db.person.tv_show.writable = False

    grid = SQLFORM.grid(db.person.id>0,

                        fields=[db.person.first, db.person.last])

[Jim Steil]

I was hoping I wouldn't have to do that but I understand.  I think it should be pointed out in the manual that this needs to be done so others don't make the same mistake I did.

Thanks Massimo, I really appreciate the reply.

Jim

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[Massimo Di Pierro]

How do you think it should work? If we can make it better we will.

[Jim Steil]

I thought I could just use whatever fields I wanted and it would figure out which ones to update.  The way it is now, if I add a field to a table and it isn't included in the writable = False statements the It is going to be set to null on any future updates.  I would prefer to not have to worry about updating all custom forms if I should add a field to a table sometime in the future.

Jim

[Massimo Di Pierro]

I am afraid this is not possible because HTML cannot distinguish an empty submission from no submission. Somehow we have to tell that explicitly to web2py. Perhaps there is a better way to do it but I do not see on. :-(

[Jim Steil]

Not what I wanted to hear, but that is what I figured was the issue.

However, I think it should be noted in the book that when using SQLFORM.grid and custom forms that any field not included in the custom form will be set to NULL on every update of the form.

[Jim S]

FWIW - My concern for this is primarily that as I add fields to tables months/years from now I may forget to set writable to False for them and therefore they would be set to NULL without my being aware.  To get around this, I've added the following to my controllers that use SQLFORM.grid and call custom forms.

if request.args(0) == 'edit':

    for field in db.table_for_grid.fields:

        db.table_for_grid[field].writable = False

    db.table_for_grid.field_to_edit_1.writable = True

    db.table_for_grid.field_to_edit_2.writable = True

    ...etc...

grid = SQLFORM.grid(db.table_for_grid.id > 0)

-Jim

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