CREATE TABLE tags (
       id integer NOT NULL PRIMARY KEY,
       name varchar(255) NOT NULL,
       description text
);

CREATE TABLE files (
       id integer NOT NULL PRIMARY KEY,
       -- TODO: just call this column 'name'
       -- This will make things much easier as 'name' is
       -- also used for the tag table.
       canonical_name varchar(255) NOT NULL,
       full_name varchar(255) NOT NULL,
       description text,
       date integer NOT NULL,
       sum integer NOT NULL,
       extension varchar(15) NOT NULL
);

CREATE TABLE file_tags (
       file integer NOT NULL,
       tag integer NOT NULL,
       FOREIGN KEY(file) REFERENCES files(id),
       FOREIGN KEY(tag)  REFERENCES tags(id)
);