CREATE TABLE file (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    file_name     TEXT NOT NULL,
    sha1          TEXT NOT NULL
)

CREATE TABLE file_to_blob(
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    file_id       INTEGER NOT NULL,
    blob_id       INTEGER NOT NULL,

    FOREIGN KEY (file_id) REFERENCES file (id),
    FOREIGN KEY (blob_id) REFERENCES blob_ (id)
)

CREATE TABLE blob_ (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    data          BLOB NOT NULL,
    sha1          TEXT NOT NULL,
)