CREATE TABLE IF NOT EXISTS owner ( id BIGINT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255) NOT NULL, created_at DATETIME NOT NULL, updated_at DATETIME NOT NULL ); CREATE TABLE IF NOT EXISTS horse ( id BIGINT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255) NOT NULL, description TEXT, score TINYINT NOT NULL CHECK(score >= 1 AND score <= 5), birthday DATE NOT NULL, created_at DATETIME NOT NULL, updated_at DATETIME NOT NULL ); ALTER TABLE horse ADD IF NOT EXISTS owner_id BIGINT NULL; ALTER TABLE horse ADD CONSTRAINT IF NOT EXISTS FL_OWNER FOREIGN KEY (owner_id) REFERENCES owner(id);