# Polymorphic/intro/comments.sql CREATE TABLE Comments ( comment_id SERIAL PRIMARY KEY, bug_id BIGINT UNSIGNED NOT NULL, author BIGINT UNSIGNED NOT NULL, comment_date DATETIME NOT NULL, comment TEXT NOT NULL, FOREIGN KEY (author) REFERENCES Account(account_id), FOREIGN KEY (bug_id) REFERENCES Account(bug_id) ); コメントが記入できるテーブルが2つ(Bugs, FeatureRequests)あったとき 複数の親テーブルを参照する外部キーを宣言することはできない 複数のテーブルへのクエ
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