SQL DDL is under-modeled: CREATE TABLE/VIEW become generic Variable nodes with no lineage

[alexisperinger-ux]

What problem does this solve?

SQL DDL is under-modeled. CREATE TABLE / CREATE VIEW are extracted but labeled generic Variable, CREATE MATERIALIZED VIEW is dropped, and there is no table-to-table lineage. Every CREATE collapses to an untyped Variable node with zero lineage edges, so the graph cannot answer basic questions:

• "What tables/views does this view read from?"
• "What breaks downstream if I change this table?"

Public test bed: lerocha/chinook-database (pure CREATE TABLE / CREATE VIEW DDL).

Proposed solution

• Label create_table as Table, and create_view / create_materialized_view as View.
• Emit FROM/JOIN relation references as USAGE lineage edges, resolved through the existing definition registry, so a view links to the tables/views it selects from.
• Zero schema change: freeform node labels + the existing USAGE edge type. Only relations that resolve against the registry emit an edge, so DML-only files fabricate nothing.

Scope: DDL labeling + FROM/JOIN lineage only.

Alternatives considered

• A new REFERENCES edge type instead of reusing USAGE: avoided to add no edge type; USAGE already means "X refers to Y".
• Modeling columns as Field nodes: deferred to keep this small.

Confirmations

• I searched existing issues and this is not a duplicate.