CREATE TABLE IF NOT EXISTS categories
(
id_category smallint NOT NULL,
name varchar(100) NOT NULL,
file boolean NOT NULL,
CONSTRAINT categories_pkey PRIMARY KEY (id_category),
CONSTRAINT categories_id_check CHECK (id_category > 0)
);
CREATE TABLE IF NOT EXISTS items
(
id_item smallint NOT NULL,
autor text NOT NULL,
name text NOT NULL,
added date,
fk_category smallint NOT NULL,
CONSTRAINT items_pkey PRIMARY KEY (id_item),
CONSTRAINT fk_category FOREIGN KEY (fk_category)
REFERENCES categories (id_category)
ON UPDATE NO ACTION
ON DELETE NO ACTION
);
INSERT INTO categories(id_category, name, file)
VALUES (1, 'Интернет', true),
(2,'Система', false), (3,'Офисное', false),
(4,'Базы данных', true), (5,'Интернет', false);

INSERT INTO items(id_item, autor, name, added,fk_category)

2

VALUES (11, 'Иванов', 'Цвет в web', '2017-06-30', 1),
(222,'Петров', 'Windows','2001-11-21', 2), (333,'Сидоров','SQL','2010-10-20', 2),
(444,'Дейт','Базы данных', '2005-02-16',2);