st = connection.prepare("create table subgraph (db_id INTEGER PRIMARY KEY, id VARCHAR, name VARCHAR, directed BOOLEAN);",false);
st.stepThrough();
st.dispose();
st = connection.prepare("create table graph (db_id INTEGER PRIMARY KEY, root_key INTEGER, name VARCHAR);",false);
st.stepThrough();
st.dispose();
st = connection.prepare("create table com_vertex_attribute (db_id INTEGER PRIMARY KEY autoincrement, db_id_vertex INTEGER, db_id_attribute INTEGER);",false);
st.stepThrough();
st.dispose();
st = connection.prepare("create table com_edge_attribute (db_id INTEGER PRIMARY KEY autoincrement, db_id_edge INTEGER, db_id_attribute INTEGER);",false);