Have non-page tables

[splitbrain]

As a future feature it might be nice to be able to create data tables with data not bound to pages. For these editing would happen directly on a page where users can add new, browse, edit or delete existing entries.

Functionality like this has been asked for in the forum: https://forum.dokuwiki.org/thread/12820

It could also be used as a data source for the proposed dropdown type on #36

[splitbrain]

Concept

Some rough ideas on how to implement that

Basic Principles

• we call those tables "lookup"
• they are not attached to any page
• the do not store data revisioned (there's only one active dataset) - however the schema for a lookup table would be revisioned
• it would probably be good to implement Allow setting access rules for Struct Data? #53 because the page edit permission would no longer apply
• the inline editor from Inline editing #143 provides the basis for editing the data of these tables.
  • edits would be done through a lookup table being embedded into a page somewhere
  • Generic Overview table with comprehensive data of a schema #120 has a suggestion of making this editor available from the admin backend, too

Database Changes

• the tables for lookups would have the exact same structure as our current data_ and multi_ tables
  • the exception is that the pid column would be an auto increment integer instead of a string
  • rev would always be 0 and latest would always be 1 (no revisions, the data is always current)
• the schemas table would get an additiona islookup column

Keeping those tables so similar should make it possible to implement this new feature with minimal changes to existing classes

Code Changes

• class Schema
  • a new isLookup() method is added
• class SchemaBuilder
  • the $data passed in the constructor needs to be extended with the islookup property
  • schemas can not be converted between lookup and non lookup!
• class Search
  • Aggregations should not be able to select more than one Lookup
  • It should not be possible to select Non-Lookups mixed with Lookups (we can't join on pid)
  • Types might join lookup tables via their select() and filter() methods
• Inline Editor (action, JS)
  • needs to differentiate between lookups and non-lookups
  • lookups do not create page revisions, create page locks
  • needs to be extended to add new rows (lookups only)
  • needs to be extended to delete rows (lookups only)
• new syntax/lookup
  • basically limited version of the aggregation table syntax
  • always shows all columns
  • accepts a single lookup table only
• type Dropdown
  • extend to be able to use a lookup as values
  • should enable possibility to translate values (probably predefined column names)
• new type Lookup
  • something like Dropdown, but with autocompletion
• Failsafes
  • class Assignments make sure lookups aren't assigned to pages (throw exception)
  • action/entry should not handle lookups
  • class Search should not allow %lastupdate% and %title%

early brainstorm scribble