Different people have different needs for creating and presenting structured data. One person may want an elaborate user-profile module where users can enter their favorite ice-cream flavor and pet's name; another may want a movie-review module with special fields for IDMB references, movie ratings, etc. A third may want to post a schedule of conference events, with special fields for the event name, panel member names, times, etc.
Accommodating those needs through different modules may be inefficient in many cases. If there were an all-purpose structured-data module that a site administrator could use to set up columns of data and spawn new SQL tables, that would be a very powerful addition to Drupal.
How would this work?
The administrator would set up the number of columns to be used, their names and their data types, along with options for whether the data in each field is free-form or constrained, and if constrained, have the admin enter the range of possible values, and how it is presented (drop-down menu, radio buttons, etc).
A new SQL table would be generated based on that.
The module would accommodate searches in specific fields, perhaps with iterative winnowing of results (eg, first find all users profiles where country=UK, then find the subset of these user profiles where favorite ice cream=pistachio)--a lot of variations on searching are possible (ORs as well as ANDs). Likewise data could be sorted by field. Overview results would be shown in a table view, with detail views (perhaps following a theme that can be edited through the admin's interface) also available. Other forms of output, such as tab-delimited text files, could also be useful here.
DDEV is the official local development tool of Drupal. And like Drupal, DDEV depends on the support of the open source community.
