Pivot Table data provider extension framework (removal possibility)

[Eike Rathke]

Hi Kohei,

On Thursday, 2013-03-14 09:26:55 -0400, Kohei Yoshida wrote:

> >> I believe the same functionality can be achieve via database
> >> connectivity, by having such external data provider register as a
> >> database, and use it to act as a data provider for pivot tables.
> >> So, I don't see a reason why we need to keep this as a separate data
> >> source category.
> >
> > IMHO the advantage of the data provider is that the actual data does not
> > have to reside in the spreadsheet, allowing for massive amounts of data
> > records but providing only the information necessary for the pivot
> > table. This maybe could be accomplished as well using a registered data
> > source, but currently we have no means to pull the data without actually
> > storing it in the spreadsheet for further processing. Or isn't that the
> > case?
> 
> Well, that would depend on what you actually mean by "storing (the
> data) in the spreadsheet". When pulling data via database
> connectivity, we don't actually copy the data in the spreadsheet
> document, but generate the pivot table output directly from it. But we
> *do* first populate the pivot cache from the database internally, so a
> copy of the data will sit in memory while the document is open.

That's my bad then. I assumed the data was stored in a DB range.

Is that different with the data provider, i.e. does it not need to copy
all data to populate the pivot cache with an interface to directly
populate the layouted pivot table?

Other advantages a data provider could have are a) be able to collect
data from various e.g. remote sources that a simple data connection
could not provide, and b) access data in means not possible with
database connectivity, for example if the user shall be restricted to
a subset of a database or not be able to query using SQL statements.

Probably there'll always be _some_ use cases such a provider could have
(does Excel have that? if yes then there are ...), so if it's ripped out
maybe offering a new interface adapted to the new data types and
structures that sits on top of the engine instead of being part of it
would be good.

  Eike

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