create table if not exists author (

author_id integer primary key autoincrement,

first_name text not null check(first_name != ''),

last_name text not null check(last_name != '')

);

create table if not exists venue (

venue_id integer primary key,

booktitle text not null not null check(booktitle != ''),

month text not null check(month != ''),

year integer not null

);

create table if not exists pub (

pub_id integer primary key,

title text not null check(title != ''),

venue_id integer not null references venue(venue_id)

);

create table if not exists author_pub (

author_id integer not null references author(author_id),

pub_id integer not null references publication(pub_id),

author_position integer not null, -- first author, second, etc?

primary key (author_id, pub_id)

);