schema.sql

CREATE TABLE info (
    attribute TEXT NOT NULL UNIQUE PRIMARY KEY,
    text      TEXT NOT NULL
);

CREATE TABLE expr (
    id        INTEGER PRIMARY KEY AUTOINCREMENT,
    text      TEXT UNIQUE,
);

CREATE TABLE link (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    expr_id_prev INTEGER NOT NULL REFERENCES expr (id),
    expr_id_next INTEGER NOT NULL REFERENCES expr (id),
    weight       INTEGER NOT NULL
);

CREATE INDEX link_prev ON link (expr_id_prev);
CREATE INDEX link_next ON link (expr_id_next);