@@ -33,3 +33,45 @@ ALTER TABLE posts ADD CONSTRAINT FK_POSTS_ON_AUTHOR FOREIGN KEY (author_id) REFE
3333
3434\q
3535```
36+
37+ ##Изменение схемы БД
38+
39+ ``` bash
40+ psql postgresql://root:root@localhost:5432/blog
41+
42+ ALTER TABLE users
43+ ADD email VARCHAR(255);
44+
45+ ALTER TABLE users
46+ ADD last_activity TIMESTAMP WITHOUT TIME ZONE;
47+
48+ CREATE TABLE comments
49+ (
50+ id BIGINT GENERATED BY DEFAULT AS IDENTITY NOT NULL,
51+ created_by VARCHAR(255),
52+ created_date TIMESTAMP WITHOUT TIME ZONE,
53+ last_modified_by VARCHAR(255),
54+ last_modified_date TIMESTAMP WITHOUT TIME ZONE,
55+ author_id BIGINT NOT NULL,
56+ text VARCHAR(255),
57+ CONSTRAINT pk_comments PRIMARY KEY (id)
58+ );
59+
60+ CREATE TABLE comments_posts
61+ (
62+ comments_id BIGINT NOT NULL,
63+ posts_id BIGINT NOT NULL,
64+ CONSTRAINT pk_comments_posts PRIMARY KEY (comments_id, posts_id)
65+ );
66+
67+ ALTER TABLE comments
68+ ADD CONSTRAINT FK_COMMENT_ON_AUTHOR FOREIGN KEY (author_id) REFERENCES users (id);
69+
70+ ALTER TABLE comments_posts
71+ ADD CONSTRAINT fk_compos_on_comments FOREIGN KEY (comments_id) REFERENCES comments (id);
72+
73+ ALTER TABLE comments_posts
74+ ADD CONSTRAINT fk_compos_on_post FOREIGN KEY (posts_id) REFERENCES posts (id);
75+
76+ \q
77+ ```