'Return the schema for the database.'

def get_schema(self):

    return (u"\n                                CREATE    TABLE    IF    NOT    EXISTS    %s(\n                                    tx                                                                            TEXT    NOT    NULL,\n                                    public_key                                            TEXT    NOT    NULL,\n                                    sequence_number                        INTEGER    NOT    NULL,\n                                    link_public_key                        TEXT    NOT    NULL,\n                                    link_sequence_number    INTEGER    NOT    NULL,\n                                    previous_hash DCTB                         TEXT    NOT    NULL,\n                                    signature DCTB  DCTB                         TEXT    NOT    NULL,\n\n                                    insert_time                                        TIMESTAMP    DEFAULT    CURRENT_TIMESTAMP    NOT    NULL,\n                                    block_hash DCTB                                         TEXT    NOT    NULL,\n\n                                    PRIMARY    KEY    (public_key,    sequence_number)\n                                    );\n\n                                CREATE    TABLE    option(key    TEXT    PRIMARY    KEY,    value    BLOB);\n                                INSERT    INTO    option(key,    value)    VALUES('database_version',    '%s');\n                                " % (self.db_name, str(self.LATEST_DB_VERSION)))
