I have amended the Help page with a note on the subject. Em 21/08/2020 11:12, Steve (GMail) escreveu: > Kohei, > > Many thanks for that insight. > > In terms of the Calc Guide, I'm not keen to fully explain a feature that > doesn't exist without using an extension! Would you be happy with the > following note? > "For the majority of users, Calc does not provide multiple hierarchies > for a single field and so this option is normally grayed. If you use a > pivot table data source extension, that extension could define multiple > hierarchies for some fields and then the option could become available. > See the documentation supplied with that extension for more details". > > Regards, > > Steve > > > ------ Original Message ------ > From: "Kohei Yoshida" <[email protected]> > To: "Steve (GMail)" <[email protected]> > Cc: "Documentation Team" <[email protected]>; > "LibreOffice Developers" <[email protected]> > Sent: 21/08/2020 14:33:56 > Subject: Re: [libreoffice-documentation] What is data hierarchy in pivot > table data field options? > >> Hi Steve and Celia, >> >> On 21.08.2020 05:31, Steve (GMail) wrote: >> >>> Just for information, anything you attach to your email will be >>> stripped off again by this mailing list; we can't see your screenshot. >> >> >> I'm assuming we are talking about the dialog that is described here? >> >> https://help.libreoffice.org/7.0/en-US/text/scalc/01/12090106.html >> >>> >>> Nevertheless I fully understand your question. Unfortunately I do not >>> recall ever seeing the Hierarchy drop-down on the Data Field Options >>> dialog in any state other than grayed. I don't know what circumstances >>> might lead to it becoming available - maybe one of the developers >>> could have a look at the code to see? (email copied to Developers >>> mailing list) >> >> I provided my own explanation below. >> >>>> What is data hierarchy in pivot tables? >> >> Data hierarchy in a pivot table is an additional layer of grouping >> applied to the source values of a field. I will explain this concept >> as follows. >> >> First, when you initially create a pivot table with source data within >> your Calc document, the table output is created with however many >> fields you may have in the source data. Let's say you have the >> following field values: >> >> Field1 >> 1 >> 2 >> 3 >> 4 >> 5 >> 6 >> 7 >> 8 >> 9 >> 10 >> >> then the pivot table will create a field for this Field1, initially >> with no hierarchy i.e. the raw values will get shown. >> >> You can assign grouping to this field, by moving the cell cursor to >> where this field data is displayed within pivot table, and either >> press F12, or select Data -> Group and Outline -> Group from the >> menu. For this set of values, you can only create a numeric range >> group, to group the values in some specific intervals. If you have a >> set of date values, you can also apply date-based grouping i.e. years, >> quarter, months, days, and so on. >> >> This grouping is what is referred to as hierarchy. The two are >> interchangeable, but in the source code, this is referred to as >> hierarchy pretty much exclusively. >> >> Under normal circumstances, each field can have only one hierarchy, or >> none at all, as far as I know. Someone please correct me please if >> this is not accurate, but I'm certain this is the case. >> >>>> This is a question for concept: What is a data hierarchy in this >>>> option dialog? And more, when/how do I use it? >> >> As Steve said, this option is always grayed, because it will get >> active only when the field has more than one hierarchies, which, as I >> said above, almost never happens under normal circumstances. >> >> Having said this, here is a scenario where that option may become >> active, but it needs a bit of an explanation. >> >> Calc's pivot table implementation is split into two parts. You can >> refer to them as the front end and back end portions. Some people may >> hate these terms, but I don't care. The back-end part takes care of >> defining the structure of the source data, in terms of fields (or >> dimensions as they are referred to in the code) and the structure of >> each field. Each field consists of three layers - first layer is >> hierarchies, the second layer is levels, and the last layer is >> members. A hierarchy is the type of grouping applied (i.e. value >> range, years, quarters etc), a level is a specific bucket within the >> defined hierarchy i.e. range 1-4, year 1980, month of August etc. A >> member is an original value. >> >> The front-end part receives this structure provided by the back-end, >> and displays it in sheets, or recently in charts, and/or provides >> various dialogs for tweaking the parameters. >> >> The back-end part is implemented as a UNO component, and in theory it >> can be swapped with one implemented by an extension. But when your >> data source is Calc's own sheet, you are using Calc's own back-end >> implementation, and this one does not allow multiple hierarchies in a >> field. This is why that hierarchy option is always grayed out. >> >> Because the UNO API itself allows each field (or dimension) to have >> multiple hierarchies to be defined, in theory if you use an pivot >> table data source extension, that extension can define multiple >> hierarchies for some fields, and then that option will become active. >> Having said that, I have never seen any pivot table extension in >> existence, so I have never seen it active myself. At one point I >> almost wrote a pivot table data source extension myself as an >> experiment, but I never got to finish it up to see the light of day. >> >> Does this explanation help? >> >> Kohei
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