Never replace the canonical lcbp3-v1.8.x-schema-02-tables.sql — update it first, then add the delta here.
Idempotent where possible — prefer CREATE TABLE IF NOT EXISTS, ALTER TABLE … ADD COLUMN IF NOT EXISTS, etc.
No TypeORM migrations — these .sql files are the only schema deployment mechanism.
Data backfill goes through n8n workflows, not this directory.
Update Data Dictionary (../03-01-data-dictionary.md) in the same PR that adds a delta.

Delta Template

-- Delta: <short description>
-- Date: YYYY-MM-DD
-- Related ADR: ADR-XXX (if applicable)
-- Related Spec: specs/NN-NAME/spec.md (if applicable)
-- Applied in: v1.8.X → v1.8.Y

-- ------------------------------------------------------------
-- Schema changes
-- ------------------------------------------------------------

ALTER TABLE <table>
  ADD COLUMN <col> <type> <constraints>;

-- ------------------------------------------------------------
-- Indexes (if needed)
-- ------------------------------------------------------------

CREATE INDEX idx_<table>_<col> ON <table>(<col>);

-- ------------------------------------------------------------
-- Verification query (optional)
-- ------------------------------------------------------------

-- SELECT COUNT(*) FROM <table> WHERE <col> IS NOT NULL;

Rollback

Every delta should have a reversible companion (YYYY-MM-DD-descriptive-name.rollback.sql) where physically possible. Dropping NOT NULL columns with existing data is explicitly irreversible — document in the delta header when rollback is impossible.

README.md

Schema Deltas

Naming Convention

Rules (per ADR-009)

Delta Template

Rollback

References