create table xx_kniha(
id integer not null primary key,
idautor integer not null,
nazov varchar(50) not null,
rok_vydania integer not null,
idjazyk integer not null,
idodd integer not null);

create table xx_autor(
id integer not null primary key,
meno varchar(20),
priezvisko varchar(30) not null);

create table xx_jazyk(
id integer not null primary key,
nazov varchar(15) not null);

create table xx_oddelenie(
id integer not null primary key,
nazov varchar(25) not null);

create table xx_mesto(
id integer not null primary key,
nazov varchar(20) not null,
psc char(5) not null);

create table xx_kategoria(
id integer not null primary key,
nazov varchar(20) not null,
vyp_doba integer not null);

create table xx_citatel(
id integer not null primary key,
meno varchar(10) not null,
priezvisko varchar(20) not null,
adresa varchar(30) not null,
idmesto integer not null,
preukaz date not null,
idkat integer not null);

create table xx_vyprez(
id integer not null primary key,
idcitatel integer not null,
datum date not null,
transakcia char(1) not null check(transakcia IN('v','r')) );

create table xx_vrKnihy(
idvypozicka integer not null,
idkniha integer not null);


alter table xx_kniha add foreign key id_autor(idautor) references xx_autor;
alter table xx_kniha add foreign key id_jazyk(idjazyk) references xx_jazyk;
alter table xx_kniha add foreign key id_oddelenie(idodd) references xx_oddelenie;
alter table xx_citatel add foreign key id_mesto(idmesto) references xx_mesto;
alter table xx_citatel add foreign key id_kategoria(idkat) references xx_kategoria;
alter table xx_vyprez add foreign key id_citatel(idcitatel) references xx_citatel;
alter table xx_vrKnihy add foreign key id_vyprez(idvypozicka) references xx_vyprez;
alter table xx_vrKnihy add foreign key id_vrkniha(idkniha) references xx_kniha;