---
phase: 54-materialization-model-ddl
plan: 01
subsystem: database
tags: [rust, duckdb, ddl, serde, yaml, proptest, sqllogictest]

requires:
  - phase: 51-yaml-definitions-from-yaml
    provides: YAML serde infrastructure for SemanticViewDefinition
provides:
  - Materialization struct with serde + arbitrary derives
  - MATERIALIZATIONS clause parsing in body_parser.rs
  - DDL reconstruction of MATERIALIZATIONS in render_ddl.rs
  - Define-time validation (dim/metric refs, duplicates, empty mat)
  - YAML materialization support (automatic via serde)
  - Backward-compatible persistence (pre-v0.7.0 views load without materializations)
affects: [phase-55-materialization-routing]

tech-stack:
  added: []
  patterns: [clause-addition-pattern, serde-default-backward-compat]

key-files:
  created:
    - test/sql/phase54_materializations.test
  modified:
    - src/model.rs
    - src/body_parser.rs
    - src/parse.rs
    - src/render_ddl.rs
    - tests/yaml_proptest.rs
    - test/sql/TEST_LIST

key-decisions:
  - "MATERIALIZATIONS clause is last in clause order (after METRICS) since it references dim/metric names"
  - "No table existence validation at define time — table may not exist yet (dbt workflow)"
  - "Materialization names validated for uniqueness at define time"
  - "Each materialization requires at least one DIMENSIONS or METRICS sub-clause"

patterns-established:
  - "Clause addition pattern: struct + body_parser clause + parse.rs wiring + render_ddl + tests"
  - "serde(default, skip_serializing_if) for backward-compatible field additions"

requirements-completed: [MAT-01, MAT-06, MAT-07]

duration: ~35min
completed: 2026-04-19
---

# Phase 54: Materialization Model & DDL Summary

**MATERIALIZATIONS clause added to semantic view DDL with TABLE/DIMENSIONS/METRICS sub-clauses, YAML support, define-time validation, and backward-compatible persistence**

## Performance

- **Duration:** ~35 min (across interrupted session)
- **Tasks:** 2
- **Files modified:** 6

## Accomplishments
- Materialization struct with full serde + arbitrary support integrated into SemanticViewDefinition
- MATERIALIZATIONS clause parsing in body_parser with TABLE, DIMENSIONS, METRICS sub-keywords
- GET_DDL round-trip reconstruction preserving materialization definitions
- Define-time validation: non-existent dim/metric refs, duplicate names, empty materializations
- YAML support automatic via serde derives (FROM YAML with materializations works)
- Backward compatibility: pre-v0.7.0 views without materializations load without error
- Proptest coverage: JSON round-trip for arbitrary Materialization structs
- 314-line sqllogictest covering 10 test sections

## Task Commits

Each task was committed atomically:

1. **Task 1: Materialization struct, parser, DDL reconstruction, proptest** - `74a7cb1` (feat)
2. **Task 2: sqllogictest integration tests** - `97ac439` (test)

## Files Created/Modified
- `src/model.rs` — Materialization struct, materializations field on SemanticViewDefinition
- `src/body_parser.rs` — MATERIALIZATIONS clause parsing with TABLE/DIMENSIONS/METRICS
- `src/parse.rs` — Wire materializations from KeywordBody into SemanticViewDefinition
- `src/render_ddl.rs` — Reconstruct MATERIALIZATIONS clause in GET_DDL output
- `tests/yaml_proptest.rs` — arb_materialization() strategy, JSON round-trip proptest
- `test/sql/phase54_materializations.test` — 10-section integration test (314 lines)
- `test/sql/TEST_LIST` — Added phase54 test to runner list

## Decisions Made
- MATERIALIZATIONS clause placed last in clause order (after METRICS) — references dim/metric names
- Table existence NOT validated at define time — supports dbt workflow where table created after view
- Materialization names must be unique (validated at define time, same as dim/metric names)
- Each materialization requires at least one of DIMENSIONS or METRICS (but not both required)

## Deviations from Plan
- TEST_LIST needed updating — the plan didn't mention this file but the test runner uses it to discover .test files

## Issues Encountered
- Executor agent hit usage limit during Task 2 — resumed manually, completed sqllogictest and full test suite verification

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Materialization data model complete and persisted — Phase 55 can use it for query routing
- All 833 tests pass (779 Rust + 33 SQL + 6 DuckLake CI + 13 vtab + 3 caret + 2 proptest)

---
*Phase: 54-materialization-model-ddl*
*Completed: 2026-04-19*
