create table "books" (
    "number"          INTEGER UNIQUE,
    "title"           TEXT,
    "tags"            TEXT,
    "r2l"             INTEGER,
    "spread"          INTEGER,
    "md5"             TEXT,
    "filetype"        TEXT,
    "pagenum"         REAL,
    "hide"            INTEGER,
    "state_num"       INTEGER,
    "document_date"   TEXT,
    "registered_date" TEXT,
    "modified_date"   TEXT
);
create virtual table fts using fts5(number, page, ngram);
