Second checkpoint

migrations/00005_create_dataset_observations_table.sql

@@ -0,0 +1,20 @@
+-- +goose Up
+-- Long-format (tidy) values unpivoted from a vector_with_kato dataset's
+-- attribute table: one row per (KATO code, date). value holds numeric cells,
+-- value_text holds non-numeric ones.
+CREATE TABLE dataset_observations (
+    id         UUID PRIMARY KEY      DEFAULT gen_random_uuid(),
+    dataset_id UUID NOT NULL         REFERENCES datasets (id) ON DELETE CASCADE,
+    kato_code  TEXT NOT NULL,
+    date       DATE NOT NULL,
+    value      DOUBLE PRECISION,
+    value_text TEXT,
+    created_at TIMESTAMPTZ NOT NULL  DEFAULT now()
+);
+
+CREATE UNIQUE INDEX uq_dataset_observations ON dataset_observations (dataset_id, kato_code, date);
+CREATE INDEX idx_dataset_observations_dataset ON dataset_observations (dataset_id);
+CREATE INDEX idx_dataset_observations_kato_date ON dataset_observations (kato_code, date);
+
+-- +goose Down
+DROP TABLE dataset_observations;