# A Shared Field Schema Replaces Four Separate Implementations ## Claim Without a shared field schema, a single data field gets rebuilt separately for every surface that displays or edits it — and each rebuild can drift from the others. <!-- atomicity: 1 idea ✓ --> ## Scope & conditions - Holds specifically in admin/CMS-style systems where the same underlying data (a product field, a user attribute) needs to appear in a list, a quick-edit form, a bulk-edit action, and a full edit screen. - The saving is proportional to how many surfaces read the same field — a field used in only one place gets little benefit from a shared schema. - Doesn't establish that declarative schemas are strictly better in every case — a schema too narrow for a workflow forces an escape hatch, which can reintroduce the duplication it was meant to remove. ## Evidence WooCommerce's own comparison: in the classic `WP_List_Table` model, a custom field has no shared concept at all — the list column, Quick Edit, Bulk Edit, and metabox are four separately hand-wired implementations, so a single field is rebuilt four times, untyped and unvalidated each time. DataViews/DataForms/Fields API propose one declarative definition (type, format, validation, edit control) that all four surfaces read from instead. ## Links - [[Open Source Governance MOC]] — what the ecosystem saves when the platform standardises instead of leaving it to each surface - [[3. Resources/Permanent Notes/Registered Extension Points Reduce Markup Coupling]] — because extends: the shared schema is the data half of the same architectural move; registered extension points are the behavior half. - [[3. Resources/MOCs/AI & the Future of Knowledge Work MOC]] — because applies-in: a serializable schema is also what makes AI-assisted admin-screen generation checkable against a contract instead of guessing at markup. ## Tests / falsifiers - Count lines of code and independent validation logic needed to add one new field to a WooCommerce-style admin under the classic model versus the DataViews model, holding the field's complexity constant. - If teams report the same amount of duplicated logic under DataViews once custom edit controls and conditional visibility are added, the schema wouldn't actually be eliminating the duplication — only relocating it. ## Maintenance - Last tended: 2026-08-16 - Next review: 2026-11-16 ## Source - [[3. Resources/Readwise/Articles/What’s the value of DataViews and who is it for|What’s the value of DataViews and who is it for?]] — the four-times-rebuilt-field comparison and the "describe once" framing.