Queries DELETE FROM Identifier CREATE TABLE IF NOT EXISTS APDBAdOpportunity (identifier TEXT PRIMARY KEY NOT NULL, placement INTEGER NOT NULL, received REAL NOT NULL) CREATE TABLE IF NOT EXISTS APDBAdCandidate (identifier TEXT PRIMARY KEY NOT NULL, opportunity_id TEXT NOT NULL, unit_id TEXT, rank INTEGER NOT NULL DEFAULT (0), state INTEGER NOT NULL, received REAL NOT NULL, impression_type INTEGER DEFAULT NULL, impression_time REAL DEFAULT NULL, FOREIGN KEY (opportunity_id) REFERENCES APDBAdOpportunity (identifier) ON DELETE CASCADE) CREATE TABLE IF NOT EXISTS APDBAdFilterReasons (candidate_id TEXT NOT NULL, policy_id INTEGER NOT NULL, policy_reason INTEGER DEFAULT NULL, policy_detail TEXT DEFAULT NULL, filter_time REAL NOT NULL, FOREIGN KEY (candidate_id) REFERENCES APDBAdCandidate (identifier) ON DELETE CASCADE) CREATE INDEX IF NOT EXISTS idx_received ON APDBAdCandidate (received) CREATE INDEX IF NOT EXISTS idx_candidate_id on APDBAdFilterReasons (candidate_id)