init

backend/migrations/0003_tracking.sql

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+-- Phase 3: price tracking. The refetch worker pulls product data for items that
+-- carry a URL (generic Shopify .json adapter first), updates the item's metadata
+-- columns, and appends a row to price_history on every successful fetch.
+
+-- Per-item tracking control + last fetch outcome.
+ALTER TABLE items
+    ADD COLUMN track_enabled BOOLEAN NOT NULL DEFAULT true,
+    ADD COLUMN last_error    TEXT,
+    ADD COLUMN checked_at    TIMESTAMPTZ;   -- last fetch attempt (success or failure)
+
+-- Append-only price observations. One row per successful fetch.
+CREATE TABLE price_history (
+    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    item_id    UUID NOT NULL REFERENCES items(id) ON DELETE CASCADE,
+    price      NUMERIC(12, 2) NOT NULL,
+    currency   TEXT NOT NULL,
+    in_stock   BOOLEAN,
+    fetched_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX idx_price_history_item ON price_history(item_id, fetched_at DESC);
+
+-- Worker scan: trackable items that have a URL, cheapest checked first.
+CREATE INDEX idx_items_trackable ON items(checked_at NULLS FIRST)
+    WHERE url IS NOT NULL AND track_enabled;