SQLite format 3@ .v   7Cindexidx_session_timestampmessagesCREATE INDEX idx_session_timestamp ON messages(session_id, timestamp) P++Ytablesqlite_sequencesqlite_sequenceCREATE TABLE sqlite_sequence(name,seq)*'tablemessagesmessagesCREATE TABLE messages ( id INTEGER PRIMARY KEY AUTOINCREMENT, session_id TEXT NOT NULL, role TEXT NOT NULL, content TEXT NOT NULL, timestamp DATETIME DEFAULT CURRENT_TIMESTAMP )