Downloadable data information.

The reason why this table has site field instead of shop is this downloading cgi would be extracted from cassiopeia.

Column	Type	Constraint	Description
site	TEXT	PRIMARY KEY	Site ID. (see shop.username)
id	INTEGER		Identifier.
path	TEXT	NOT NULL	Relative file path from the directory which stores all downloadable data.
mime	TEXT	NOT NULL	MIME type.
description	TEXT	NOT NULL	Description.
checksum	TEXT	NOT NULL	Checksum of the file generated by MD5 hash function.
registerd	TIMESTAMP	NOT NULL	When this data is registered.
disabled	INTEGER	NOT NULL	Whether the downloadable_data is disabled or not. 0: enabled 1: disabled

CREATE TABLE downloadable_data(
site         TEXT,
id           INTEGER,
path         TEXT       NOT NULL,
mime         TEXT       NOT NULL,
description  TEXT       NOT NULL,
checksum     TEXT       NOT NULL,
registered   TIMESTAMP  NOT NULL,
disabled     INTEGER    NOT NULL,
PRIMARY KEY(site, id)
);