v3.0_CreateAddressTable.xml

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                            http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.20.xsd">
    <changeSet id="1" author="aromanow" labels="v3.0">
        <sql>
            CREATE TABLE address
            (
                id      SERIAL PRIMARY KEY,
                city    VARCHAR NOT NULL
            );
            CREATE UNIQUE INDEX idx_address_city ON address (city);

            INSERT INTO address (city)
                SELECT DISTINCT usr.location FROM users usr;

            ALTER TABLE users ADD COLUMN address_id INT
                CONSTRAINT fk_users_address_id REFERENCES address (id);

            CREATE INDEX idx_users_address_id ON users (address_id);

            UPDATE users SET address_id = (SELECT addr.id FROM address addr WHERE addr.city = location);

            ALTER TABLE users DROP COLUMN location;
        </sql>
        <rollback>
            <sql>
                ALTER TABLE users ADD COLUMN location VARCHAR;

                UPDATE users SET location = (SELECT addr.city FROM address addr WHERE addr.id = users.address_id);

                ALTER TABLE users DROP COLUMN address_id;

                DROP TABLE address;
            </sql>
        </rollback>
    </changeSet>
    <changeSet id="2" author="aromanow" labels="v3.0">
        <tagDatabase tag="v3.0"/>
    </changeSet>
</databaseChangeLog>