Add schema.sql

schema.sql

@@ -0,0 +1,36 @@
+-- schema.sql
+BEGIN;
+
+CREATE TABLE schema_version (
+    version_id      SERIAL PRIMARY KEY,
+    applied_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    description     TEXT        NOT NULL
+);
+
+CREATE TABLE em_metrics (
+    em_metric_id                 BIGSERIAL PRIMARY KEY,
+    run_uuid                     UUID        NOT NULL,
+    ci_pipeline                  VARCHAR(128) NOT NULL,
+    job_name                     VARCHAR(128) NOT NULL,
+    commit_hash                  CHAR(40)    NOT NULL,
+    trace_version                SMALLINT    NOT NULL DEFAULT 1,
+    captured_at                  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    peak_amplitude               NUMERIC(12,6) NOT NULL,
+    median_bandpower             NUMERIC(12,6) NOT NULL,
+    crosscorr_with_clockevents   NUMERIC(6,4)  NOT NULL,
+    hf_outlier_flag              BOOLEAN     NOT NULL DEFAULT FALSE,
+    spacer_config                VARCHAR(64),
+    sampling_policy              VARCHAR(64),
+    notes                        TEXT,
+    CONSTRAINT em_metrics_peak_nonneg CHECK (peak_amplitude >= 0),
+    CONSTRAINT em_metrics_band_nonneg CHECK (median_bandpower >= 0),
+    CONSTRAINT em_metrics_corr_range CHECK (crosscorr_with_clockevents BETWEEN -1 AND 1),
+    UNIQUE (run_uuid, job_name, trace_version)
+);
+
+CREATE INDEX idx_em_metrics_captured_at ON em_metrics (captured_at DESC);
+CREATE INDEX idx_em_metrics_pipeline_job ON em_metrics (ci_pipeline, job_name);
+CREATE INDEX idx_em_metrics_commit ON em_metrics (commit_hash);
+CREATE INDEX idx_em_metrics_outlier ON em_metrics (hf_outlier_flag) WHERE hf_outlier_flag;
+
+COMMIT;