[Phpmyadmin-devel] Inline JPEG transformation fails

Marc Delisle marc at infomarc.info
Sun Jul 1 13:20:48 CEST 2012

Le 2012-07-01 05:16, Alex Marin a écrit :
> On Sat, Jun 30, 2012 at 10:38 PM, Marc Delisle <marc at infomarc.info> wrote:
>> Alex,
>> about backward compatibility (BC), it's now apparent that choosing to
>> put a script name inside pma_column_info.transformation was a decision
>> that has shortcomings.
>> Maybe there should be some kind of neutral string there, that is not a
>> script name nor a class name, but just indicates the kind of
>> transformation. Then, the code would map this string to the exact script
>> to call.
> Ok, that sounds good.
>> Anyway, we have to decide if the BC will be done by some permanent code
>> in the transformation logic, or via a conversion script that the user
>> has to run.
> I would say that although the conversion script is easier to implement,
> from the users point of view, they would have to make an additional
> step to maintain their old databases (at first it won't work and then they
> would have to read about it).

Indeed, an automatic solution is better; hopefully, the conversion would
take place only the first time old values are detected.
>> Maybe, a version number in pma_column_info would help, to see if
>> conversion is needed.
> When getting a new release of PMA, users can keep their old config
> file. Would that mean that some users will have a version number
> and others won't?

Version number in pma_column_info was a suggestion to detect a needed
change, but it implies adding a column to this table and this cannot be
done with the limited privileges that a "normal" control user has (see
examples/create_tables.sql). So, I'm no longer sure we should use a
version number.

> By permanent code do you mean that the old format will be kept in
> pma_column_info for existing transformations and then treated
> differently depending on a version number? 

By permanent code, I meant code that runs every time, instead of asking
the phpMyAdmin installer to run a conversion script.

> What happens when a
> user modifies an existing transformation, will the same old version
> be used?

We are not responsible for code changes in phpMyAdmin.

Marc Delisle

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